Merge tag 'asoc-fix-v5.17-rc4' of https://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6-block.git] / arch / x86 / Kconfig
CommitLineData
b2441318 1# SPDX-License-Identifier: GPL-2.0
daa93fab
SR
2# Select 32 or 64 bit
3config 64BIT
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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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JB
25 def_bool y
26 depends on 64BIT
d94e0685 27 # Options that are inherently 64-bit kernel only:
4eb0716e 28 select ARCH_HAS_GIGANTIC_PAGE
c12d3362 29 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
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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
63703f37 36 select ZONE_DMA32
1032c0ba 37
518049d9
SRV
38config FORCE_DYNAMIC_FTRACE
39 def_bool y
40 depends on X86_32
41 depends on FUNCTION_TRACER
42 select DYNAMIC_FTRACE
43 help
44 We keep the static function tracing (!DYNAMIC_FTRACE) around
45 in order to test the non static function tracing in the
46 generic code, as other architectures still use it. But we
47 only need to keep it around for x86_64. No need to keep it
48 for x86_32. For x86_32, force DYNAMIC_FTRACE.
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IM
49#
50# Arch settings
51#
52# ( Note that options that are marked 'if X86_64' could in principle be
53# ported to 32-bit as well. )
54#
8d5fffb9 55config X86
3c2362e6 56 def_bool y
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IM
57 #
58 # Note: keep this list sorted alphabetically
59 #
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IM
60 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
61 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
942fa985 62 select ARCH_32BIT_OFF_T if X86_32
2a21ad57 63 select ARCH_CLOCKSOURCE_INIT
1f6d3a8f 64 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
1e866974 65 select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
5c11f00b 66 select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
91024b3c 67 select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
cebc774f 68 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
1e866974 69 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
c763ea26 70 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
c2280be8 71 select ARCH_HAS_CACHE_LINE_SIZE
fa5b6ec9 72 select ARCH_HAS_DEBUG_VIRTUAL
399145f9 73 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE
21266be9 74 select ARCH_HAS_DEVMEM_IS_ALLOWED
b1a57bbf 75 select ARCH_HAS_EARLY_DEBUG if KGDB
6471b825 76 select ARCH_HAS_ELF_RANDOMIZE
72d93104 77 select ARCH_HAS_FAST_MULTIPLIER
316d097c 78 select ARCH_HAS_FILTER_PGPROT
6974f0c4 79 select ARCH_HAS_FORTIFY_SOURCE
957e3fac 80 select ARCH_HAS_GCOV_PROFILE_ALL
bece04b5 81 select ARCH_HAS_KCOV if X86_64
0c9c1d56 82 select ARCH_HAS_MEM_ENCRYPT
10bcc80e 83 select ARCH_HAS_MEMBARRIER_SYNC_CORE
0ebeea8c 84 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
c763ea26 85 select ARCH_HAS_PMEM_API if X86_64
17596731 86 select ARCH_HAS_PTE_DEVMAP if X86_64
3010a5ea 87 select ARCH_HAS_PTE_SPECIAL
0aed55af 88 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
ec6347bb 89 select ARCH_HAS_COPY_MC if X86_64
d2852a22 90 select ARCH_HAS_SET_MEMORY
d253ca0c 91 select ARCH_HAS_SET_DIRECT_MAP
ad21fc4f
LA
92 select ARCH_HAS_STRICT_KERNEL_RWX
93 select ARCH_HAS_STRICT_MODULE_RWX
ac1ab12a 94 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
25c619e5 95 select ARCH_HAS_SYSCALL_WRAPPER
c6d30853 96 select ARCH_HAS_UBSAN_SANITIZE_ALL
7e01ccb4 97 select ARCH_HAS_DEBUG_WX
63703f37 98 select ARCH_HAS_ZONE_DMA_SET if EXPERT
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IM
99 select ARCH_HAVE_NMI_SAFE_CMPXCHG
100 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
77fbbc81 101 select ARCH_MIGHT_HAVE_PC_PARPORT
5e2c18c0 102 select ARCH_MIGHT_HAVE_PC_SERIO
3599fe12 103 select ARCH_STACKWALK
2c870e61 104 select ARCH_SUPPORTS_ACPI
6471b825 105 select ARCH_SUPPORTS_ATOMIC_RMW
5d6ad668 106 select ARCH_SUPPORTS_DEBUG_PAGEALLOC
d283d422 107 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64
6471b825 108 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
14df3267 109 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096
583bfd48
NC
110 select ARCH_SUPPORTS_LTO_CLANG
111 select ARCH_SUPPORTS_LTO_CLANG_THIN
6471b825 112 select ARCH_USE_BUILTIN_BSWAP
dce44566 113 select ARCH_USE_MEMTEST
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IM
114 select ARCH_USE_QUEUED_RWLOCKS
115 select ARCH_USE_QUEUED_SPINLOCKS
2ce0d7f9 116 select ARCH_USE_SYM_ANNOTATIONS
ce4a4e56 117 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
81c22041 118 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64
c763ea26 119 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
51c2ee6d 120 select ARCH_WANTS_NO_INSTR
3876d4a3 121 select ARCH_WANT_HUGE_PMD_SHARE
59612b24 122 select ARCH_WANT_LD_ORPHAN_WARN
38d8b4e6 123 select ARCH_WANTS_THP_SWAP if X86_64
b5f06f64 124 select ARCH_HAS_PARANOID_L1D_FLUSH
10916706 125 select BUILDTIME_TABLE_SORT
6471b825 126 select CLKEVT_I8253
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IM
127 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
128 select CLOCKSOURCE_WATCHDOG
6471b825 129 select DCACHE_WORD_ACCESS
3aac3ebe 130 select DYNAMIC_SIGFRAME
45471cd9
LT
131 select EDAC_ATOMIC_SCRUB
132 select EDAC_SUPPORT
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IM
133 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
134 select GENERIC_CLOCKEVENTS_MIN_ADJUST
135 select GENERIC_CMOS_UPDATE
136 select GENERIC_CPU_AUTOPROBE
61dc0f55 137 select GENERIC_CPU_VULNERABILITIES
5b7c73e0 138 select GENERIC_EARLY_IOREMAP
27d6b4d1 139 select GENERIC_ENTRY
6471b825 140 select GENERIC_IOMAP
c7d6c9dd 141 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
0fa115da 142 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
ad7a929f 143 select GENERIC_IRQ_MIGRATION if SMP
6471b825 144 select GENERIC_IRQ_PROBE
c201c917 145 select GENERIC_IRQ_RESERVATION_MODE
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IM
146 select GENERIC_IRQ_SHOW
147 select GENERIC_PENDING_IRQ if SMP
2ae27137 148 select GENERIC_PTDUMP
6471b825 149 select GENERIC_SMP_IDLE_THREAD
6471b825 150 select GENERIC_TIME_VSYSCALL
7ac87074 151 select GENERIC_GETTIMEOFDAY
550a77a7 152 select GENERIC_VDSO_TIME_NS
39656e83 153 select GUP_GET_PTE_LOW_HIGH if X86_PAE
17e5888e 154 select HARDIRQS_SW_RESEND
7edaeb68 155 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
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IM
156 select HAVE_ACPI_APEI if ACPI
157 select HAVE_ACPI_APEI_NMI if ACPI
158 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
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IM
159 select HAVE_ARCH_AUDITSYSCALL
160 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
161 select HAVE_ARCH_JUMP_LABEL
b34006c4 162 select HAVE_ARCH_JUMP_LABEL_RELATIVE
d17a1d97 163 select HAVE_ARCH_KASAN if X86_64
0609ae01 164 select HAVE_ARCH_KASAN_VMALLOC if X86_64
1dc0da6e 165 select HAVE_ARCH_KFENCE
6471b825 166 select HAVE_ARCH_KGDB
9e08f57d
DC
167 select HAVE_ARCH_MMAP_RND_BITS if MMU
168 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
1b028f78 169 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
271ca788 170 select HAVE_ARCH_PREL32_RELOCATIONS
6471b825 171 select HAVE_ARCH_SECCOMP_FILTER
f7d83c1c 172 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
afaef01c 173 select HAVE_ARCH_STACKLEAK
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IM
174 select HAVE_ARCH_TRACEHOOK
175 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
a00cc7d9 176 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
b64d8d1e 177 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
7677f7fd 178 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD
e37e43a4 179 select HAVE_ARCH_VMAP_STACK if X86_64
fe950f60 180 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
c763ea26 181 select HAVE_ARCH_WITHIN_STACK_FRAMES
2ff2b7ec 182 select HAVE_ASM_MODVERSIONS
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IM
183 select HAVE_CMPXCHG_DOUBLE
184 select HAVE_CMPXCHG_LOCAL
185 select HAVE_CONTEXT_TRACKING if X86_64
d1f250e2 186 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING
cf4db259 187 select HAVE_C_RECORDMCOUNT
6dafca97 188 select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION
6471b825 189 select HAVE_DEBUG_KMEMLEAK
6471b825 190 select HAVE_DMA_CONTIGUOUS
677aa9f7 191 select HAVE_DYNAMIC_FTRACE
06aeaaea 192 select HAVE_DYNAMIC_FTRACE_WITH_REGS
02a474ca 193 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64
562955fe 194 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
c316eb44 195 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64
503e4510 196 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64
03f5781b 197 select HAVE_EBPF_JIT
58340a07 198 select HAVE_EFFICIENT_UNALIGNED_ACCESS
6630a8e5 199 select HAVE_EISA
5f56a5df 200 select HAVE_EXIT_THREAD
67a929e0 201 select HAVE_FAST_GUP
644e0e8d 202 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
6471b825 203 select HAVE_FTRACE_MCOUNT_RECORD
4a30e4c9 204 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE)
6471b825 205 select HAVE_FUNCTION_TRACER
6b90bd4b 206 select HAVE_GCC_PLUGINS
6471b825 207 select HAVE_HW_BREAKPOINT
6471b825 208 select HAVE_IOREMAP_PROT
624db9ea 209 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
6471b825 210 select HAVE_IRQ_TIME_ACCOUNTING
2e9f3bdd 211 select HAVE_KERNEL_BZIP2
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IM
212 select HAVE_KERNEL_GZIP
213 select HAVE_KERNEL_LZ4
2e9f3bdd 214 select HAVE_KERNEL_LZMA
13510997 215 select HAVE_KERNEL_LZO
6471b825 216 select HAVE_KERNEL_XZ
fb46d057 217 select HAVE_KERNEL_ZSTD
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IM
218 select HAVE_KPROBES
219 select HAVE_KPROBES_ON_FTRACE
540adea3 220 select HAVE_FUNCTION_ERROR_INJECTION
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IM
221 select HAVE_KRETPROBES
222 select HAVE_KVM
223 select HAVE_LIVEPATCH if X86_64
0102752e 224 select HAVE_MIXED_BREAKPOINTS_REGS
ee9f8fce 225 select HAVE_MOD_ARCH_SPECIFIC
9f132f7e 226 select HAVE_MOVE_PMD
be37c98d 227 select HAVE_MOVE_PUD
42a0bb3f 228 select HAVE_NMI
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IM
229 select HAVE_OPTPROBES
230 select HAVE_PCSPKR_PLATFORM
231 select HAVE_PERF_EVENTS
c01d4323 232 select HAVE_PERF_EVENTS_NMI
92e5aae4 233 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
eb01d42a 234 select HAVE_PCI
c5e63197 235 select HAVE_PERF_REGS
c5ebcedb 236 select HAVE_PERF_USER_STACK_DUMP
ff2e6d72 237 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
00998085 238 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
6471b825 239 select HAVE_REGS_AND_STACK_ACCESS_API
6415b38b 240 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
3c88ee19 241 select HAVE_FUNCTION_ARG_ACCESS_API
7ecd19cf 242 select HAVE_SETUP_PER_CPU_AREA
cd1a41ce 243 select HAVE_SOFTIRQ_ON_OWN_STACK
d148eac0 244 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
c763ea26 245 select HAVE_STACK_VALIDATION if X86_64
e6d6c071 246 select HAVE_STATIC_CALL
1e7e4788 247 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION
6ef869e0 248 select HAVE_PREEMPT_DYNAMIC
d6761b8f 249 select HAVE_RSEQ
6471b825 250 select HAVE_SYSCALL_TRACEPOINTS
6471b825 251 select HAVE_UNSTABLE_SCHED_CLOCK
7c68af6e 252 select HAVE_USER_RETURN_NOTIFIER
7ac87074 253 select HAVE_GENERIC_VDSO
05736e4a 254 select HOTPLUG_SMT if SMP
c0185808 255 select IRQ_FORCED_THREADING
7ecd19cf
KW
256 select NEED_PER_CPU_EMBED_FIRST_CHUNK
257 select NEED_PER_CPU_PAGE_FIRST_CHUNK
86596f0a 258 select NEED_SG_DMA_LENGTH
2eac9c2d 259 select PCI_DOMAINS if PCI
625210cf 260 select PCI_LOCKLESS_CONFIG if PCI
6471b825 261 select PERF_EVENTS
3195ef59 262 select RTC_LIB
d6faca40 263 select RTC_MC146818_LIB
6471b825 264 select SPARSE_IRQ
83fe27ea 265 select SRCU
1e7e4788 266 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
6471b825 267 select SYSCTL_EXCEPTION_TRACE
15f4eae7 268 select THREAD_INFO_IN_TASK
4aae683f 269 select TRACE_IRQFLAGS_SUPPORT
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IM
270 select USER_STACKTRACE_SUPPORT
271 select VIRT_TO_BUS
3b02a051 272 select HAVE_ARCH_KCSAN if X86_64
6471b825 273 select X86_FEATURE_NAMES if PROC_FS
0c608dad 274 select PROC_PID_ARCH_STATUS if PROC_FS
50468e43 275 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX
9e2b4be3 276 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
7d8330a5 277
ba7e4d13 278config INSTRUCTION_DECODER
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JB
279 def_bool y
280 depends on KPROBES || PERF_EVENTS || UPROBES
ba7e4d13 281
51b26ada
LT
282config OUTPUT_FORMAT
283 string
284 default "elf32-i386" if X86_32
285 default "elf64-x86-64" if X86_64
286
8d5fffb9 287config LOCKDEP_SUPPORT
3c2362e6 288 def_bool y
8d5fffb9
SR
289
290config STACKTRACE_SUPPORT
3c2362e6 291 def_bool y
8d5fffb9 292
8d5fffb9 293config MMU
3c2362e6 294 def_bool y
8d5fffb9 295
9e08f57d
DC
296config ARCH_MMAP_RND_BITS_MIN
297 default 28 if 64BIT
298 default 8
299
300config ARCH_MMAP_RND_BITS_MAX
301 default 32 if 64BIT
302 default 16
303
304config ARCH_MMAP_RND_COMPAT_BITS_MIN
305 default 8
306
307config ARCH_MMAP_RND_COMPAT_BITS_MAX
308 default 16
309
8d5fffb9
SR
310config SBUS
311 bool
312
313config GENERIC_ISA_DMA
3120e25e
JB
314 def_bool y
315 depends on ISA_DMA_API
8d5fffb9 316
8d5fffb9 317config GENERIC_BUG
3c2362e6 318 def_bool y
8d5fffb9 319 depends on BUG
b93a531e
JB
320 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
321
322config GENERIC_BUG_RELATIVE_POINTERS
323 bool
8d5fffb9 324
8d5fffb9 325config ARCH_MAY_HAVE_PC_FDC
3120e25e
JB
326 def_bool y
327 depends on ISA_DMA_API
8d5fffb9 328
1032c0ba
SR
329config GENERIC_CALIBRATE_DELAY
330 def_bool y
331
9a0b8415 332config ARCH_HAS_CPU_RELAX
333 def_bool y
334
316d097c
DH
335config ARCH_HAS_FILTER_PGPROT
336 def_bool y
337
801e4062
JB
338config ARCH_HIBERNATION_POSSIBLE
339 def_bool y
801e4062 340
d7109fe3
AS
341config ARCH_NR_GPIO
342 int
343 default 1024 if X86_64
344 default 512
345
f4cb5700
JB
346config ARCH_SUSPEND_POSSIBLE
347 def_bool y
f4cb5700 348
53313b2c
SC
349config ARCH_WANT_GENERAL_HUGETLB
350 def_bool y
351
8d5fffb9 352config AUDIT_ARCH
e0fd24a3 353 def_bool y if X86_64
8d5fffb9 354
d6f2d75a
AR
355config KASAN_SHADOW_OFFSET
356 hex
357 depends on KASAN
358 default 0xdffffc0000000000
359
69575d38
SW
360config HAVE_INTEL_TXT
361 def_bool y
6ea30386 362 depends on INTEL_IOMMU && ACPI
69575d38 363
6b0c3d44
SR
364config X86_32_SMP
365 def_bool y
366 depends on X86_32 && SMP
367
368config X86_64_SMP
369 def_bool y
370 depends on X86_64 && SMP
371
2b144498
SD
372config ARCH_SUPPORTS_UPROBES
373 def_bool y
374
d20642f0
RH
375config FIX_EARLYCON_MEM
376 def_bool y
377
94d49eb3
KS
378config DYNAMIC_PHYSICAL_MASK
379 bool
380
98233368
KS
381config PGTABLE_LEVELS
382 int
77ef56e4 383 default 5 if X86_5LEVEL
98233368
KS
384 default 4 if X86_64
385 default 3 if X86_PAE
386 default 2
387
2a61f474
MY
388config CC_HAS_SANE_STACKPROTECTOR
389 bool
390 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
391 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
392 help
393 We have to make sure stack protector is unconditionally disabled if
3fb0fdb3
AL
394 the compiler produces broken code or if it does not let us control
395 the segment on 32-bit kernels.
2a61f474 396
506f1d07
SR
397menu "Processor type and features"
398
506f1d07
SR
399config SMP
400 bool "Symmetric multi-processing support"
a7f7f624 401 help
506f1d07 402 This enables support for systems with more than one CPU. If you have
4a474157
RG
403 a system with only one CPU, say N. If you have a system with more
404 than one CPU, say Y.
506f1d07 405
4a474157 406 If you say N here, the kernel will run on uni- and multiprocessor
506f1d07
SR
407 machines, but will use only one CPU of a multiprocessor machine. If
408 you say Y here, the kernel will run on many, but not all,
4a474157 409 uniprocessor machines. On a uniprocessor machine, the kernel
506f1d07
SR
410 will run faster if you say N here.
411
412 Note that if you say Y here and choose architecture "586" or
413 "Pentium" under "Processor family", the kernel will not work on 486
414 architectures. Similarly, multiprocessor kernels for the "PPro"
415 architecture may not work on all Pentium based boards.
416
417 People using multiprocessor machines who say Y here should also say
418 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
419 Management" code will be disabled if you say Y here.
420
cb1aaebe 421 See also <file:Documentation/x86/i386/IO-APIC.rst>,
4f4cfa6c 422 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
506f1d07
SR
423 <http://www.tldp.org/docs.html#howto>.
424
425 If you don't know what to do here, say N.
426
9def39be
JT
427config X86_FEATURE_NAMES
428 bool "Processor feature human-readable names" if EMBEDDED
429 default y
a7f7f624 430 help
9def39be
JT
431 This option compiles in a table of x86 feature bits and corresponding
432 names. This is required to support /proc/cpuinfo and a few kernel
433 messages. You can disable this to save space, at the expense of
434 making those few kernel messages show numeric feature bits instead.
435
436 If in doubt, say Y.
437
06cd9a7d
YL
438config X86_X2APIC
439 bool "Support x2apic"
19e3d60d 440 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
a7f7f624 441 help
06cd9a7d
YL
442 This enables x2apic support on CPUs that have this feature.
443
444 This allows 32-bit apic IDs (so it can support very large systems),
445 and accesses the local apic via MSRs not via mmio.
446
06cd9a7d
YL
447 If you don't know what to do here, say N.
448
6695c85b 449config X86_MPPARSE
4590d98f 450 bool "Enable MPS table" if ACPI
7a527688 451 default y
5ab74722 452 depends on X86_LOCAL_APIC
a7f7f624 453 help
6695c85b
YL
454 For old smp systems that do not have proper acpi support. Newer systems
455 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
6695c85b 456
ddd70cf9 457config GOLDFISH
b03b016f
KK
458 def_bool y
459 depends on X86_GOLDFISH
ddd70cf9 460
76b04384
DW
461config RETPOLINE
462 bool "Avoid speculative indirect branches in kernel"
463 default y
464 help
465 Compile kernel with the retpoline compiler options to guard against
466 kernel-to-user data leaks by avoiding speculative indirect
467 branches. Requires a compiler with -mindirect-branch=thunk-extern
468 support for full protection. The kernel may run slower.
469
e463a09a
PZ
470config CC_HAS_SLS
471 def_bool $(cc-option,-mharden-sls=all)
472
473config SLS
474 bool "Mitigate Straight-Line-Speculation"
475 depends on CC_HAS_SLS && X86_64
476 default n
477 help
478 Compile the kernel with straight-line-speculation options to guard
479 against straight line speculation. The kernel image might be slightly
480 larger.
481
e6d42931
JW
482config X86_CPU_RESCTRL
483 bool "x86 CPU resource control support"
6fe07ce3 484 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
59fe5a77 485 select KERNFS
e79f15a4 486 select PROC_CPU_RESCTRL if PROC_FS
78e99b4a 487 help
e6d42931 488 Enable x86 CPU resource control support.
6fe07ce3
BM
489
490 Provide support for the allocation and monitoring of system resources
491 usage by the CPU.
492
493 Intel calls this Intel Resource Director Technology
494 (Intel(R) RDT). More information about RDT can be found in the
495 Intel x86 Architecture Software Developer Manual.
496
497 AMD calls this AMD Platform Quality of Service (AMD QoS).
498 More information about AMD QoS can be found in the AMD64 Technology
499 Platform Quality of Service Extensions manual.
78e99b4a
FY
500
501 Say N if unsure.
502
8425091f 503if X86_32
a0d0bb4d
RD
504config X86_BIGSMP
505 bool "Support for big SMP systems with more than 8 CPUs"
506 depends on SMP
a7f7f624 507 help
e133f6ea 508 This option is needed for the systems that have more than 8 CPUs.
a0d0bb4d 509
c5c606d9
RT
510config X86_EXTENDED_PLATFORM
511 bool "Support for extended (non-PC) x86 platforms"
512 default y
a7f7f624 513 help
06ac8346
IM
514 If you disable this option then the kernel will only support
515 standard PC platforms. (which covers the vast majority of
516 systems out there.)
517
8425091f
RT
518 If you enable this option then you'll be able to select support
519 for the following (non-PC) 32 bit x86 platforms:
cb7b8023 520 Goldfish (Android emulator)
8425091f 521 AMD Elan
8425091f
RT
522 RDC R-321x SoC
523 SGI 320/540 (Visual Workstation)
83125a3a 524 STA2X11-based (e.g. Northville)
3f4110a4 525 Moorestown MID devices
06ac8346
IM
526
527 If you have one of these systems, or if you want to build a
528 generic distribution kernel, say Y here - otherwise say N.
8425091f 529endif
06ac8346 530
8425091f
RT
531if X86_64
532config X86_EXTENDED_PLATFORM
533 bool "Support for extended (non-PC) x86 platforms"
534 default y
a7f7f624 535 help
8425091f
RT
536 If you disable this option then the kernel will only support
537 standard PC platforms. (which covers the vast majority of
538 systems out there.)
539
540 If you enable this option then you'll be able to select support
541 for the following (non-PC) 64 bit x86 platforms:
44b111b5 542 Numascale NumaChip
8425091f
RT
543 ScaleMP vSMP
544 SGI Ultraviolet
545
546 If you have one of these systems, or if you want to build a
547 generic distribution kernel, say Y here - otherwise say N.
548endif
c5c606d9
RT
549# This is an alphabetically sorted list of 64 bit extended platforms
550# Please maintain the alphabetic order if and when there are additions
44b111b5
SP
551config X86_NUMACHIP
552 bool "Numascale NumaChip"
553 depends on X86_64
554 depends on X86_EXTENDED_PLATFORM
555 depends on NUMA
556 depends on SMP
557 depends on X86_X2APIC
f9726bfd 558 depends on PCI_MMCONFIG
a7f7f624 559 help
44b111b5
SP
560 Adds support for Numascale NumaChip large-SMP systems. Needed to
561 enable more than ~168 cores.
562 If you don't have one of these, you should say N here.
506f1d07 563
c5c606d9
RT
564config X86_VSMP
565 bool "ScaleMP vSMP"
6276a074 566 select HYPERVISOR_GUEST
c5c606d9
RT
567 select PARAVIRT
568 depends on X86_64 && PCI
569 depends on X86_EXTENDED_PLATFORM
ead91d4b 570 depends on SMP
a7f7f624 571 help
c5c606d9
RT
572 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
573 supposed to run on these EM64T-based machines. Only choose this option
574 if you have one of these machines.
5e3a77e9 575
03b48632
NP
576config X86_UV
577 bool "SGI Ultraviolet"
578 depends on X86_64
c5c606d9 579 depends on X86_EXTENDED_PLATFORM
54c28d29 580 depends on NUMA
1ecb4ae5 581 depends on EFI
c2209ea5 582 depends on KEXEC_CORE
9d6c26e7 583 depends on X86_X2APIC
1222e564 584 depends on PCI
a7f7f624 585 help
03b48632
NP
586 This option is needed in order to support SGI Ultraviolet systems.
587 If you don't have one of these, you should say N here.
588
c5c606d9
RT
589# Following is an alphabetically sorted list of 32 bit extended platforms
590# Please maintain the alphabetic order if and when there are additions
506f1d07 591
ddd70cf9 592config X86_GOLDFISH
b03b016f
KK
593 bool "Goldfish (Virtual Platform)"
594 depends on X86_EXTENDED_PLATFORM
a7f7f624 595 help
ddd70cf9
JN
596 Enable support for the Goldfish virtual platform used primarily
597 for Android development. Unless you are building for the Android
598 Goldfish emulator say N here.
599
c751e17b
TG
600config X86_INTEL_CE
601 bool "CE4100 TV platform"
602 depends on PCI
603 depends on PCI_GODIRECT
6084a6e2 604 depends on X86_IO_APIC
c751e17b
TG
605 depends on X86_32
606 depends on X86_EXTENDED_PLATFORM
37bc9f50 607 select X86_REBOOTFIXUPS
da6b737b
SAS
608 select OF
609 select OF_EARLY_FLATTREE
a7f7f624 610 help
c751e17b
TG
611 Select for the Intel CE media processor (CE4100) SOC.
612 This option compiles in support for the CE4100 SOC for settop
613 boxes and media devices.
614
4cb9b00f 615config X86_INTEL_MID
43605ef1 616 bool "Intel MID platform support"
43605ef1 617 depends on X86_EXTENDED_PLATFORM
edc6bc78 618 depends on X86_PLATFORM_DEVICES
1ea7c673 619 depends on PCI
3fda5bb4 620 depends on X86_64 || (PCI_GOANY && X86_32)
1ea7c673 621 depends on X86_IO_APIC
4cb9b00f 622 select I2C
7c9c3a1e 623 select DW_APB_TIMER
54b34aa0 624 select INTEL_SCU_PCI
a7f7f624 625 help
4cb9b00f
DC
626 Select to build a kernel capable of supporting Intel MID (Mobile
627 Internet Device) platform systems which do not have the PCI legacy
628 interfaces. If you are building for a PC class system say N here.
1ea7c673 629
4cb9b00f
DC
630 Intel MID platforms are based on an Intel processor and chipset which
631 consume less power than most of the x86 derivatives.
43605ef1 632
8bbc2a13
BD
633config X86_INTEL_QUARK
634 bool "Intel Quark platform support"
635 depends on X86_32
636 depends on X86_EXTENDED_PLATFORM
637 depends on X86_PLATFORM_DEVICES
638 depends on X86_TSC
639 depends on PCI
640 depends on PCI_GOANY
641 depends on X86_IO_APIC
642 select IOSF_MBI
643 select INTEL_IMR
9ab6eb51 644 select COMMON_CLK
a7f7f624 645 help
8bbc2a13
BD
646 Select to include support for Quark X1000 SoC.
647 Say Y here if you have a Quark based system such as the Arduino
648 compatible Intel Galileo.
649
3d48aab1
MW
650config X86_INTEL_LPSS
651 bool "Intel Low Power Subsystem Support"
5962dd22 652 depends on X86 && ACPI && PCI
3d48aab1 653 select COMMON_CLK
0f531431 654 select PINCTRL
eebb3e8d 655 select IOSF_MBI
a7f7f624 656 help
3d48aab1
MW
657 Select to build support for Intel Low Power Subsystem such as
658 found on Intel Lynxpoint PCH. Selecting this option enables
0f531431
MN
659 things like clock tree (common clock framework) and pincontrol
660 which are needed by the LPSS peripheral drivers.
3d48aab1 661
92082a88
KX
662config X86_AMD_PLATFORM_DEVICE
663 bool "AMD ACPI2Platform devices support"
664 depends on ACPI
665 select COMMON_CLK
666 select PINCTRL
a7f7f624 667 help
92082a88
KX
668 Select to interpret AMD specific ACPI device to platform device
669 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
670 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
671 implemented under PINCTRL subsystem.
672
ced3ce76
DB
673config IOSF_MBI
674 tristate "Intel SoC IOSF Sideband support for SoC platforms"
675 depends on PCI
a7f7f624 676 help
ced3ce76
DB
677 This option enables sideband register access support for Intel SoC
678 platforms. On these platforms the IOSF sideband is used in lieu of
679 MSR's for some register accesses, mostly but not limited to thermal
680 and power. Drivers may query the availability of this device to
681 determine if they need the sideband in order to work on these
682 platforms. The sideband is available on the following SoC products.
683 This list is not meant to be exclusive.
684 - BayTrail
685 - Braswell
686 - Quark
687
688 You should say Y if you are running a kernel on one of these SoC's.
689
ed2226bd
DB
690config IOSF_MBI_DEBUG
691 bool "Enable IOSF sideband access through debugfs"
692 depends on IOSF_MBI && DEBUG_FS
a7f7f624 693 help
ed2226bd
DB
694 Select this option to expose the IOSF sideband access registers (MCR,
695 MDR, MCRX) through debugfs to write and read register information from
696 different units on the SoC. This is most useful for obtaining device
697 state information for debug and analysis. As this is a general access
698 mechanism, users of this option would have specific knowledge of the
699 device they want to access.
700
701 If you don't require the option or are in doubt, say N.
702
c5c606d9
RT
703config X86_RDC321X
704 bool "RDC R-321x SoC"
506f1d07 705 depends on X86_32
c5c606d9
RT
706 depends on X86_EXTENDED_PLATFORM
707 select M486
708 select X86_REBOOTFIXUPS
a7f7f624 709 help
c5c606d9
RT
710 This option is needed for RDC R-321x system-on-chip, also known
711 as R-8610-(G).
712 If you don't have one of these chips, you should say N here.
713
e0c7ae37 714config X86_32_NON_STANDARD
9c398017
IM
715 bool "Support non-standard 32-bit SMP architectures"
716 depends on X86_32 && SMP
c5c606d9 717 depends on X86_EXTENDED_PLATFORM
a7f7f624 718 help
b5660ba7
PA
719 This option compiles in the bigsmp and STA2X11 default
720 subarchitectures. It is intended for a generic binary
721 kernel. If you select them all, kernel will probe it one by
722 one and will fallback to default.
d49c4288 723
c5c606d9 724# Alphabetically sorted list of Non standard 32 bit platforms
d49c4288 725
d949f36f 726config X86_SUPPORTS_MEMORY_FAILURE
6fc108a0 727 def_bool y
d949f36f
LT
728 # MCE code calls memory_failure():
729 depends on X86_MCE
730 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
d949f36f
LT
731 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
732 depends on X86_64 || !SPARSEMEM
733 select ARCH_SUPPORTS_MEMORY_FAILURE
d949f36f 734
83125a3a
AR
735config STA2X11
736 bool "STA2X11 Companion Chip Support"
737 depends on X86_32_NON_STANDARD && PCI
83125a3a
AR
738 select SWIOTLB
739 select MFD_STA2X11
0145071b 740 select GPIOLIB
a7f7f624 741 help
83125a3a
AR
742 This adds support for boards based on the STA2X11 IO-Hub,
743 a.k.a. "ConneXt". The chip is used in place of the standard
744 PC chipset, so all "standard" peripherals are missing. If this
745 option is selected the kernel will still be able to boot on
746 standard PC machines.
747
82148d1d
S
748config X86_32_IRIS
749 tristate "Eurobraille/Iris poweroff module"
750 depends on X86_32
a7f7f624 751 help
82148d1d
S
752 The Iris machines from EuroBraille do not have APM or ACPI support
753 to shut themselves down properly. A special I/O sequence is
754 needed to do so, which is what this module does at
755 kernel shutdown.
756
757 This is only for Iris machines from EuroBraille.
758
759 If unused, say N.
760
ae1e9130 761config SCHED_OMIT_FRAME_POINTER
3c2362e6
HH
762 def_bool y
763 prompt "Single-depth WCHAN output"
a87d0914 764 depends on X86
a7f7f624 765 help
506f1d07
SR
766 Calculate simpler /proc/<PID>/wchan values. If this option
767 is disabled then wchan values will recurse back to the
768 caller function. This provides more accurate wchan values,
769 at the expense of slightly more scheduling overhead.
770
771 If in doubt, say "Y".
772
6276a074
BP
773menuconfig HYPERVISOR_GUEST
774 bool "Linux guest support"
a7f7f624 775 help
6276a074
BP
776 Say Y here to enable options for running Linux under various hyper-
777 visors. This option enables basic hypervisor detection and platform
778 setup.
506f1d07 779
6276a074
BP
780 If you say N, all options in this submenu will be skipped and
781 disabled, and Linux guest support won't be built in.
506f1d07 782
6276a074 783if HYPERVISOR_GUEST
506f1d07 784
e61bd94a
EPH
785config PARAVIRT
786 bool "Enable paravirtualization code"
a0e2bf7c 787 depends on HAVE_STATIC_CALL
a7f7f624 788 help
e61bd94a
EPH
789 This changes the kernel so it can modify itself when it is run
790 under a hypervisor, potentially improving performance significantly
791 over full virtualization. However, when run without a hypervisor
792 the kernel is theoretically slower and slightly larger.
793
c00a280a
JG
794config PARAVIRT_XXL
795 bool
796
6276a074
BP
797config PARAVIRT_DEBUG
798 bool "paravirt-ops debugging"
799 depends on PARAVIRT && DEBUG_KERNEL
a7f7f624 800 help
6276a074
BP
801 Enable to debug paravirt_ops internals. Specifically, BUG if
802 a paravirt_op is missing when it is called.
803
b4ecc126
JF
804config PARAVIRT_SPINLOCKS
805 bool "Paravirtualization layer for spinlocks"
6ea30386 806 depends on PARAVIRT && SMP
a7f7f624 807 help
b4ecc126
JF
808 Paravirtualized spinlocks allow a pvops backend to replace the
809 spinlock implementation with something virtualization-friendly
810 (for example, block the virtual CPU rather than spinning).
811
4c4e4f61
R
812 It has a minimal impact on native kernels and gives a nice performance
813 benefit on paravirtualized KVM / Xen kernels.
b4ecc126 814
4c4e4f61 815 If you are unsure how to answer this question, answer Y.
b4ecc126 816
ecca2502
ZY
817config X86_HV_CALLBACK_VECTOR
818 def_bool n
819
6276a074 820source "arch/x86/xen/Kconfig"
7af192c9 821
6276a074
BP
822config KVM_GUEST
823 bool "KVM Guest support (including kvmclock)"
824 depends on PARAVIRT
825 select PARAVIRT_CLOCK
a1c4423b 826 select ARCH_CPUIDLE_HALTPOLL
b1d40575 827 select X86_HV_CALLBACK_VECTOR
6276a074 828 default y
a7f7f624 829 help
6276a074
BP
830 This option enables various optimizations for running under the KVM
831 hypervisor. It includes a paravirtualized clock, so that instead
832 of relying on a PIT (or probably other) emulation by the
833 underlying device model, the host provides the guest with
834 timing infrastructure such as time of day, and system time
506f1d07 835
a1c4423b 836config ARCH_CPUIDLE_HALTPOLL
b03b016f
KK
837 def_bool n
838 prompt "Disable host haltpoll when loading haltpoll driver"
839 help
a1c4423b
MT
840 If virtualized under KVM, disable host haltpoll.
841
7733607f
MW
842config PVH
843 bool "Support for running PVH guests"
a7f7f624 844 help
7733607f
MW
845 This option enables the PVH entry point for guest virtual machines
846 as specified in the x86/HVM direct boot ABI.
847
6276a074
BP
848config PARAVIRT_TIME_ACCOUNTING
849 bool "Paravirtual steal time accounting"
850 depends on PARAVIRT
a7f7f624 851 help
6276a074
BP
852 Select this option to enable fine granularity task steal time
853 accounting. Time spent executing other tasks in parallel with
854 the current vCPU is discounted from the vCPU power. To account for
855 that, there can be a small performance impact.
856
857 If in doubt, say N here.
858
859config PARAVIRT_CLOCK
860 bool
97349135 861
4a362601
JK
862config JAILHOUSE_GUEST
863 bool "Jailhouse non-root cell support"
abde587b 864 depends on X86_64 && PCI
87e65d05 865 select X86_PM_TIMER
a7f7f624 866 help
4a362601
JK
867 This option allows to run Linux as guest in a Jailhouse non-root
868 cell. You can leave this option disabled if you only want to start
869 Jailhouse and run Linux afterwards in the root cell.
870
ec7972c9
ZY
871config ACRN_GUEST
872 bool "ACRN Guest support"
873 depends on X86_64
498ad393 874 select X86_HV_CALLBACK_VECTOR
ec7972c9
ZY
875 help
876 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
877 a flexible, lightweight reference open-source hypervisor, built with
878 real-time and safety-criticality in mind. It is built for embedded
879 IOT with small footprint and real-time features. More details can be
880 found in https://projectacrn.org/.
881
6276a074 882endif #HYPERVISOR_GUEST
97349135 883
506f1d07
SR
884source "arch/x86/Kconfig.cpu"
885
886config HPET_TIMER
3c2362e6 887 def_bool X86_64
506f1d07 888 prompt "HPET Timer Support" if X86_32
a7f7f624 889 help
8f9ca475
IM
890 Use the IA-PC HPET (High Precision Event Timer) to manage
891 time in preference to the PIT and RTC, if a HPET is
892 present.
893 HPET is the next generation timer replacing legacy 8254s.
894 The HPET provides a stable time base on SMP
895 systems, unlike the TSC, but it is more expensive to access,
4e7f9df2
MT
896 as it is off-chip. The interface used is documented
897 in the HPET spec, revision 1.
506f1d07 898
8f9ca475
IM
899 You can safely choose Y here. However, HPET will only be
900 activated if the platform and the BIOS support this feature.
901 Otherwise the 8254 will be used for timing services.
506f1d07 902
8f9ca475 903 Choose N to continue using the legacy 8254 timer.
506f1d07
SR
904
905config HPET_EMULATE_RTC
3c2362e6 906 def_bool y
3228e1dc 907 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
506f1d07 908
6a108a14 909# Mark as expert because too many people got it wrong.
506f1d07 910# The code disables itself when not needed.
7ae9392c
TP
911config DMI
912 default y
cf074402 913 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
6a108a14 914 bool "Enable DMI scanning" if EXPERT
a7f7f624 915 help
7ae9392c
TP
916 Enabled scanning of DMI to identify machine quirks. Say Y
917 here unless you have verified that your setup is not
918 affected by entries in the DMI blacklist. Required by PNP
919 BIOS code.
920
506f1d07 921config GART_IOMMU
38901f1c 922 bool "Old AMD GART IOMMU support"
2f9237d4 923 select DMA_OPS
a4ce5a48 924 select IOMMU_HELPER
506f1d07 925 select SWIOTLB
23ac4ae8 926 depends on X86_64 && PCI && AMD_NB
a7f7f624 927 help
ced3c42c
IM
928 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
929 GART based hardware IOMMUs.
930
931 The GART supports full DMA access for devices with 32-bit access
932 limitations, on systems with more than 3 GB. This is usually needed
933 for USB, sound, many IDE/SATA chipsets and some other devices.
934
935 Newer systems typically have a modern AMD IOMMU, supported via
936 the CONFIG_AMD_IOMMU=y config option.
937
938 In normal configurations this driver is only active when needed:
939 there's more than 3 GB of memory and the system contains a
940 32-bit limited device.
941
942 If unsure, say Y.
506f1d07 943
1184dc2f 944config MAXSMP
ddb0c5a6 945 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
6ea30386 946 depends on X86_64 && SMP && DEBUG_KERNEL
36f5101a 947 select CPUMASK_OFFSTACK
a7f7f624 948 help
ddb0c5a6 949 Enable maximum number of CPUS and NUMA Nodes for this architecture.
1184dc2f 950 If unsure, say N.
506f1d07 951
aec6487e
IM
952#
953# The maximum number of CPUs supported:
954#
955# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
956# and which can be configured interactively in the
957# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
958#
959# The ranges are different on 32-bit and 64-bit kernels, depending on
960# hardware capabilities and scalability features of the kernel.
961#
962# ( If MAXSMP is enabled we just use the highest possible value and disable
963# interactive configuration. )
964#
965
966config NR_CPUS_RANGE_BEGIN
a0d0bb4d 967 int
aec6487e
IM
968 default NR_CPUS_RANGE_END if MAXSMP
969 default 1 if !SMP
970 default 2
a0d0bb4d 971
aec6487e 972config NR_CPUS_RANGE_END
a0d0bb4d 973 int
aec6487e
IM
974 depends on X86_32
975 default 64 if SMP && X86_BIGSMP
976 default 8 if SMP && !X86_BIGSMP
977 default 1 if !SMP
a0d0bb4d 978
aec6487e 979config NR_CPUS_RANGE_END
a0d0bb4d 980 int
aec6487e 981 depends on X86_64
1edae1ae
SW
982 default 8192 if SMP && CPUMASK_OFFSTACK
983 default 512 if SMP && !CPUMASK_OFFSTACK
aec6487e 984 default 1 if !SMP
a0d0bb4d 985
aec6487e 986config NR_CPUS_DEFAULT
a0d0bb4d
RD
987 int
988 depends on X86_32
aec6487e
IM
989 default 32 if X86_BIGSMP
990 default 8 if SMP
991 default 1 if !SMP
a0d0bb4d 992
aec6487e 993config NR_CPUS_DEFAULT
a0d0bb4d
RD
994 int
995 depends on X86_64
aec6487e
IM
996 default 8192 if MAXSMP
997 default 64 if SMP
998 default 1 if !SMP
a0d0bb4d 999
506f1d07 1000config NR_CPUS
36f5101a 1001 int "Maximum number of CPUs" if SMP && !MAXSMP
aec6487e
IM
1002 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1003 default NR_CPUS_DEFAULT
a7f7f624 1004 help
506f1d07 1005 This allows you to specify the maximum number of CPUs which this
bb61ccc7 1006 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
cad14bb9 1007 supported value is 8192, otherwise the maximum value is 512. The
506f1d07
SR
1008 minimum value which makes sense is 2.
1009
aec6487e
IM
1010 This is purely to save memory: each supported CPU adds about 8KB
1011 to the kernel image.
506f1d07 1012
66558b73
TC
1013config SCHED_CLUSTER
1014 bool "Cluster scheduler support"
1015 depends on SMP
1016 default y
1017 help
1018 Cluster scheduler support improves the CPU scheduler's decision
1019 making when dealing with machines that have clusters of CPUs.
1020 Cluster usually means a couple of CPUs which are placed closely
1021 by sharing mid-level caches, last-level cache tags or internal
1022 busses.
1023
506f1d07 1024config SCHED_SMT
dbe73364 1025 def_bool y if SMP
506f1d07
SR
1026
1027config SCHED_MC
3c2362e6
HH
1028 def_bool y
1029 prompt "Multi-core scheduler support"
c8e56d20 1030 depends on SMP
a7f7f624 1031 help
506f1d07
SR
1032 Multi-core scheduler support improves the CPU scheduler's decision
1033 making when dealing with multi-core CPU chips at a cost of slightly
1034 increased overhead in some places. If unsure say N here.
1035
de966cf4
TC
1036config SCHED_MC_PRIO
1037 bool "CPU core priorities scheduler support"
0a21fc12
IM
1038 depends on SCHED_MC && CPU_SUP_INTEL
1039 select X86_INTEL_PSTATE
1040 select CPU_FREQ
de966cf4 1041 default y
a7f7f624 1042 help
0a21fc12
IM
1043 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1044 core ordering determined at manufacturing time, which allows
1045 certain cores to reach higher turbo frequencies (when running
1046 single threaded workloads) than others.
de966cf4 1047
0a21fc12
IM
1048 Enabling this kernel feature teaches the scheduler about
1049 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1050 scheduler's CPU selection logic accordingly, so that higher
1051 overall system performance can be achieved.
de966cf4 1052
0a21fc12 1053 This feature will have no effect on CPUs without this feature.
de966cf4 1054
0a21fc12 1055 If unsure say Y here.
5e76b2ab 1056
30b8b006 1057config UP_LATE_INIT
b03b016f
KK
1058 def_bool y
1059 depends on !SMP && X86_LOCAL_APIC
30b8b006 1060
506f1d07 1061config X86_UP_APIC
50849eef
JB
1062 bool "Local APIC support on uniprocessors" if !PCI_MSI
1063 default PCI_MSI
38a1dfda 1064 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
a7f7f624 1065 help
506f1d07
SR
1066 A local APIC (Advanced Programmable Interrupt Controller) is an
1067 integrated interrupt controller in the CPU. If you have a single-CPU
1068 system which has a processor with a local APIC, you can say Y here to
1069 enable and use it. If you say Y here even though your machine doesn't
1070 have a local APIC, then the kernel will still run with no slowdown at
1071 all. The local APIC supports CPU-generated self-interrupts (timer,
1072 performance counters), and the NMI watchdog which detects hard
1073 lockups.
1074
1075config X86_UP_IOAPIC
1076 bool "IO-APIC support on uniprocessors"
1077 depends on X86_UP_APIC
a7f7f624 1078 help
506f1d07
SR
1079 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1080 SMP-capable replacement for PC-style interrupt controllers. Most
1081 SMP systems and many recent uniprocessor systems have one.
1082
1083 If you have a single-CPU system with an IO-APIC, you can say Y here
1084 to use it. If you say Y here even though your machine doesn't have
1085 an IO-APIC, then the kernel will still run with no slowdown at all.
1086
1087config X86_LOCAL_APIC
3c2362e6 1088 def_bool y
0dbc6078 1089 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
b5dc8e6c 1090 select IRQ_DOMAIN_HIERARCHY
52f518a3 1091 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
506f1d07
SR
1092
1093config X86_IO_APIC
b1da1e71
JB
1094 def_bool y
1095 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
506f1d07 1096
41b9eb26
SA
1097config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1098 bool "Reroute for broken boot IRQs"
41b9eb26 1099 depends on X86_IO_APIC
a7f7f624 1100 help
41b9eb26
SA
1101 This option enables a workaround that fixes a source of
1102 spurious interrupts. This is recommended when threaded
1103 interrupt handling is used on systems where the generation of
1104 superfluous "boot interrupts" cannot be disabled.
1105
1106 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1107 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1108 kernel does during interrupt handling). On chipsets where this
1109 boot IRQ generation cannot be disabled, this workaround keeps
1110 the original IRQ line masked so that only the equivalent "boot
1111 IRQ" is delivered to the CPUs. The workaround also tells the
1112 kernel to set up the IRQ handler on the boot IRQ line. In this
1113 way only one interrupt is delivered to the kernel. Otherwise
1114 the spurious second interrupt may cause the kernel to bring
1115 down (vital) interrupt lines.
1116
1117 Only affects "broken" chipsets. Interrupt sharing may be
1118 increased on these systems.
1119
506f1d07 1120config X86_MCE
bab9bc65 1121 bool "Machine Check / overheating reporting"
648ed940 1122 select GENERIC_ALLOCATOR
e57dbaf7 1123 default y
a7f7f624 1124 help
bab9bc65
AK
1125 Machine Check support allows the processor to notify the
1126 kernel if it detects a problem (e.g. overheating, data corruption).
506f1d07 1127 The action the kernel takes depends on the severity of the problem,
bab9bc65 1128 ranging from warning messages to halting the machine.
4efc0670 1129
5de97c9f
TL
1130config X86_MCELOG_LEGACY
1131 bool "Support for deprecated /dev/mcelog character device"
1132 depends on X86_MCE
a7f7f624 1133 help
5de97c9f
TL
1134 Enable support for /dev/mcelog which is needed by the old mcelog
1135 userspace logging daemon. Consider switching to the new generation
1136 rasdaemon solution.
1137
506f1d07 1138config X86_MCE_INTEL
3c2362e6
HH
1139 def_bool y
1140 prompt "Intel MCE features"
c1ebf835 1141 depends on X86_MCE && X86_LOCAL_APIC
a7f7f624 1142 help
506f1d07
SR
1143 Additional support for intel specific MCE features such as
1144 the thermal monitor.
1145
1146config X86_MCE_AMD
3c2362e6
HH
1147 def_bool y
1148 prompt "AMD MCE features"
f5382de9 1149 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
a7f7f624 1150 help
506f1d07
SR
1151 Additional support for AMD specific MCE features such as
1152 the DRAM Error Threshold.
1153
4efc0670 1154config X86_ANCIENT_MCE
6fc108a0 1155 bool "Support for old Pentium 5 / WinChip machine checks"
c31d9633 1156 depends on X86_32 && X86_MCE
a7f7f624 1157 help
cd13adcc 1158 Include support for machine check handling on old Pentium 5 or WinChip
5065a706 1159 systems. These typically need to be enabled explicitly on the command
cd13adcc 1160 line.
4efc0670 1161
b2762686
AK
1162config X86_MCE_THRESHOLD
1163 depends on X86_MCE_AMD || X86_MCE_INTEL
6fc108a0 1164 def_bool y
b2762686 1165
ea149b36 1166config X86_MCE_INJECT
bc8e80d5 1167 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
ea149b36 1168 tristate "Machine check injector support"
a7f7f624 1169 help
ea149b36
AK
1170 Provide support for injecting machine checks for testing purposes.
1171 If you don't know what a machine check is and you don't do kernel
1172 QA it is safe to say n.
1173
07dc900e 1174source "arch/x86/events/Kconfig"
e633c65a 1175
5aef51c3 1176config X86_LEGACY_VM86
1e642812 1177 bool "Legacy VM86 support"
506f1d07 1178 depends on X86_32
a7f7f624 1179 help
5aef51c3
AL
1180 This option allows user programs to put the CPU into V8086
1181 mode, which is an 80286-era approximation of 16-bit real mode.
1182
1183 Some very old versions of X and/or vbetool require this option
1184 for user mode setting. Similarly, DOSEMU will use it if
1185 available to accelerate real mode DOS programs. However, any
1186 recent version of DOSEMU, X, or vbetool should be fully
1187 functional even without kernel VM86 support, as they will all
1e642812
IM
1188 fall back to software emulation. Nevertheless, if you are using
1189 a 16-bit DOS program where 16-bit performance matters, vm86
1190 mode might be faster than emulation and you might want to
1191 enable this option.
5aef51c3 1192
1e642812
IM
1193 Note that any app that works on a 64-bit kernel is unlikely to
1194 need this option, as 64-bit kernels don't, and can't, support
1195 V8086 mode. This option is also unrelated to 16-bit protected
1196 mode and is not needed to run most 16-bit programs under Wine.
5aef51c3 1197
1e642812
IM
1198 Enabling this option increases the complexity of the kernel
1199 and slows down exception handling a tiny bit.
5aef51c3 1200
1e642812 1201 If unsure, say N here.
5aef51c3
AL
1202
1203config VM86
b03b016f
KK
1204 bool
1205 default X86_LEGACY_VM86
34273f41
PA
1206
1207config X86_16BIT
1208 bool "Enable support for 16-bit segments" if EXPERT
1209 default y
a5b9e5a2 1210 depends on MODIFY_LDT_SYSCALL
a7f7f624 1211 help
34273f41
PA
1212 This option is required by programs like Wine to run 16-bit
1213 protected mode legacy code on x86 processors. Disabling
1214 this option saves about 300 bytes on i386, or around 6K text
1215 plus 16K runtime memory on x86-64,
1216
1217config X86_ESPFIX32
1218 def_bool y
1219 depends on X86_16BIT && X86_32
506f1d07 1220
197725de
PA
1221config X86_ESPFIX64
1222 def_bool y
34273f41 1223 depends on X86_16BIT && X86_64
506f1d07 1224
1ad83c85 1225config X86_VSYSCALL_EMULATION
b03b016f
KK
1226 bool "Enable vsyscall emulation" if EXPERT
1227 default y
1228 depends on X86_64
a7f7f624 1229 help
1ad83c85
AL
1230 This enables emulation of the legacy vsyscall page. Disabling
1231 it is roughly equivalent to booting with vsyscall=none, except
1232 that it will also disable the helpful warning if a program
1233 tries to use a vsyscall. With this option set to N, offending
1234 programs will just segfault, citing addresses of the form
1235 0xffffffffff600?00.
1236
1237 This option is required by many programs built before 2013, and
1238 care should be used even with newer programs if set to N.
1239
1240 Disabling this option saves about 7K of kernel size and
1241 possibly 4K of additional runtime pagetable memory.
1242
111e7b15
TG
1243config X86_IOPL_IOPERM
1244 bool "IOPERM and IOPL Emulation"
a24ca997 1245 default y
a7f7f624 1246 help
111e7b15
TG
1247 This enables the ioperm() and iopl() syscalls which are necessary
1248 for legacy applications.
1249
c8137ace
TG
1250 Legacy IOPL support is an overbroad mechanism which allows user
1251 space aside of accessing all 65536 I/O ports also to disable
1252 interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1253 capabilities and permission from potentially active security
1254 modules.
1255
1256 The emulation restricts the functionality of the syscall to
1257 only allowing the full range I/O port access, but prevents the
a24ca997
TG
1258 ability to disable interrupts from user space which would be
1259 granted if the hardware IOPL mechanism would be used.
c8137ace 1260
506f1d07
SR
1261config TOSHIBA
1262 tristate "Toshiba Laptop support"
1263 depends on X86_32
a7f7f624 1264 help
506f1d07
SR
1265 This adds a driver to safely access the System Management Mode of
1266 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1267 not work on models with a Phoenix BIOS. The System Management Mode
1268 is used to set the BIOS and power saving options on Toshiba portables.
1269
1270 For information on utilities to make use of this driver see the
1271 Toshiba Linux utilities web site at:
1272 <http://www.buzzard.org.uk/toshiba/>.
1273
1274 Say Y if you intend to run this kernel on a Toshiba portable.
1275 Say N otherwise.
1276
1277config I8K
039ae585 1278 tristate "Dell i8k legacy laptop support"
ef775a0e
RD
1279 depends on HWMON
1280 depends on PROC_FS
039ae585 1281 select SENSORS_DELL_SMM
a7f7f624 1282 help
039ae585
PR
1283 This option enables legacy /proc/i8k userspace interface in hwmon
1284 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1285 temperature and allows controlling fan speeds of Dell laptops via
1286 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1287 it reports also power and hotkey status. For fan speed control is
1288 needed userspace package i8kutils.
1289
1290 Say Y if you intend to run this kernel on old Dell laptops or want to
1291 use userspace package i8kutils.
506f1d07
SR
1292 Say N otherwise.
1293
1294config X86_REBOOTFIXUPS
9ba16087
JB
1295 bool "Enable X86 board specific fixups for reboot"
1296 depends on X86_32
a7f7f624 1297 help
506f1d07
SR
1298 This enables chipset and/or board specific fixups to be done
1299 in order to get reboot to work correctly. This is only needed on
1300 some combinations of hardware and BIOS. The symptom, for which
1301 this config is intended, is when reboot ends with a stalled/hung
1302 system.
1303
1304 Currently, the only fixup is for the Geode machines using
5e3a77e9 1305 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
506f1d07
SR
1306
1307 Say Y if you want to enable the fixup. Currently, it's safe to
1308 enable this option even if you don't need it.
1309 Say N otherwise.
1310
1311config MICROCODE
9a2bc335
BP
1312 bool "CPU microcode loading support"
1313 default y
80030e3d 1314 depends on CPU_SUP_AMD || CPU_SUP_INTEL
a7f7f624 1315 help
506f1d07 1316 If you say Y here, you will be able to update the microcode on
5f9c01aa
BP
1317 Intel and AMD processors. The Intel support is for the IA32 family,
1318 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1319 AMD support is for families 0x10 and later. You will obviously need
1320 the actual microcode binary data itself which is not shipped with
1321 the Linux kernel.
1322
1323 The preferred method to load microcode from a detached initrd is described
cb1aaebe 1324 in Documentation/x86/microcode.rst. For that you need to enable
5f9c01aa
BP
1325 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1326 initrd for microcode blobs.
1327
c508c46e
BG
1328 In addition, you can build the microcode into the kernel. For that you
1329 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1330 config option.
506f1d07 1331
8d86f390 1332config MICROCODE_INTEL
e43f6e67 1333 bool "Intel microcode loading support"
8f9ca475
IM
1334 depends on MICROCODE
1335 default MICROCODE
a7f7f624 1336 help
8f9ca475
IM
1337 This options enables microcode patch loading support for Intel
1338 processors.
1339
b8989db9
A
1340 For the current Intel microcode data package go to
1341 <https://downloadcenter.intel.com> and search for
1342 'Linux Processor Microcode Data File'.
8d86f390 1343
80cc9f10 1344config MICROCODE_AMD
e43f6e67 1345 bool "AMD microcode loading support"
8f9ca475 1346 depends on MICROCODE
a7f7f624 1347 help
8f9ca475
IM
1348 If you select this option, microcode patch loading support for AMD
1349 processors will be enabled.
80cc9f10 1350
8f9ca475 1351config MICROCODE_OLD_INTERFACE
c02f48e0
BP
1352 bool "Ancient loading interface (DEPRECATED)"
1353 default n
506f1d07 1354 depends on MICROCODE
a7f7f624 1355 help
c02f48e0
BP
1356 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1357 which was used by userspace tools like iucode_tool and microcode.ctl.
1358 It is inadequate because it runs too late to be able to properly
1359 load microcode on a machine and it needs special tools. Instead, you
1360 should've switched to the early loading method with the initrd or
cb1aaebe 1361 builtin microcode by now: Documentation/x86/microcode.rst
506f1d07
SR
1362
1363config X86_MSR
1364 tristate "/dev/cpu/*/msr - Model-specific register support"
a7f7f624 1365 help
506f1d07
SR
1366 This device gives privileged processes access to the x86
1367 Model-Specific Registers (MSRs). It is a character device with
1368 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1369 MSR accesses are directed to a specific CPU on multi-processor
1370 systems.
1371
1372config X86_CPUID
1373 tristate "/dev/cpu/*/cpuid - CPU information support"
a7f7f624 1374 help
506f1d07
SR
1375 This device gives processes access to the x86 CPUID instruction to
1376 be executed on a specific processor. It is a character device
1377 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1378 /dev/cpu/31/cpuid.
1379
1380choice
1381 prompt "High Memory Support"
6fc108a0 1382 default HIGHMEM4G
506f1d07
SR
1383 depends on X86_32
1384
1385config NOHIGHMEM
1386 bool "off"
a7f7f624 1387 help
506f1d07
SR
1388 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1389 However, the address space of 32-bit x86 processors is only 4
1390 Gigabytes large. That means that, if you have a large amount of
1391 physical memory, not all of it can be "permanently mapped" by the
1392 kernel. The physical memory that's not permanently mapped is called
1393 "high memory".
1394
1395 If you are compiling a kernel which will never run on a machine with
1396 more than 1 Gigabyte total physical RAM, answer "off" here (default
1397 choice and suitable for most users). This will result in a "3GB/1GB"
1398 split: 3GB are mapped so that each process sees a 3GB virtual memory
1399 space and the remaining part of the 4GB virtual memory space is used
1400 by the kernel to permanently map as much physical memory as
1401 possible.
1402
1403 If the machine has between 1 and 4 Gigabytes physical RAM, then
1404 answer "4GB" here.
1405
1406 If more than 4 Gigabytes is used then answer "64GB" here. This
1407 selection turns Intel PAE (Physical Address Extension) mode on.
1408 PAE implements 3-level paging on IA32 processors. PAE is fully
1409 supported by Linux, PAE mode is implemented on all recent Intel
1410 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1411 then the kernel will not boot on CPUs that don't support PAE!
1412
1413 The actual amount of total physical memory will either be
1414 auto detected or can be forced by using a kernel command line option
1415 such as "mem=256M". (Try "man bootparam" or see the documentation of
1416 your boot loader (lilo or loadlin) about how to pass options to the
1417 kernel at boot time.)
1418
1419 If unsure, say "off".
1420
1421config HIGHMEM4G
1422 bool "4GB"
a7f7f624 1423 help
506f1d07
SR
1424 Select this if you have a 32-bit processor and between 1 and 4
1425 gigabytes of physical RAM.
1426
1427config HIGHMEM64G
1428 bool "64GB"
225bac2d 1429 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
506f1d07 1430 select X86_PAE
a7f7f624 1431 help
506f1d07
SR
1432 Select this if you have a 32-bit processor and more than 4
1433 gigabytes of physical RAM.
1434
1435endchoice
1436
1437choice
6a108a14 1438 prompt "Memory split" if EXPERT
506f1d07
SR
1439 default VMSPLIT_3G
1440 depends on X86_32
a7f7f624 1441 help
506f1d07
SR
1442 Select the desired split between kernel and user memory.
1443
1444 If the address range available to the kernel is less than the
1445 physical memory installed, the remaining memory will be available
1446 as "high memory". Accessing high memory is a little more costly
1447 than low memory, as it needs to be mapped into the kernel first.
1448 Note that increasing the kernel address space limits the range
1449 available to user programs, making the address space there
1450 tighter. Selecting anything other than the default 3G/1G split
1451 will also likely make your kernel incompatible with binary-only
1452 kernel modules.
1453
1454 If you are not absolutely sure what you are doing, leave this
1455 option alone!
1456
1457 config VMSPLIT_3G
1458 bool "3G/1G user/kernel split"
1459 config VMSPLIT_3G_OPT
1460 depends on !X86_PAE
1461 bool "3G/1G user/kernel split (for full 1G low memory)"
1462 config VMSPLIT_2G
1463 bool "2G/2G user/kernel split"
1464 config VMSPLIT_2G_OPT
1465 depends on !X86_PAE
1466 bool "2G/2G user/kernel split (for full 2G low memory)"
1467 config VMSPLIT_1G
1468 bool "1G/3G user/kernel split"
1469endchoice
1470
1471config PAGE_OFFSET
1472 hex
1473 default 0xB0000000 if VMSPLIT_3G_OPT
1474 default 0x80000000 if VMSPLIT_2G
1475 default 0x78000000 if VMSPLIT_2G_OPT
1476 default 0x40000000 if VMSPLIT_1G
1477 default 0xC0000000
1478 depends on X86_32
1479
1480config HIGHMEM
3c2362e6 1481 def_bool y
506f1d07 1482 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
506f1d07
SR
1483
1484config X86_PAE
9ba16087 1485 bool "PAE (Physical Address Extension) Support"
506f1d07 1486 depends on X86_32 && !HIGHMEM4G
d4a451d5 1487 select PHYS_ADDR_T_64BIT
9d99c712 1488 select SWIOTLB
a7f7f624 1489 help
506f1d07
SR
1490 PAE is required for NX support, and furthermore enables
1491 larger swapspace support for non-overcommit purposes. It
1492 has the cost of more pagetable lookup overhead, and also
1493 consumes more pagetable space per process.
1494
77ef56e4
KS
1495config X86_5LEVEL
1496 bool "Enable 5-level page tables support"
18ec1eaf 1497 default y
eedb92ab 1498 select DYNAMIC_MEMORY_LAYOUT
162434e7 1499 select SPARSEMEM_VMEMMAP
77ef56e4 1500 depends on X86_64
a7f7f624 1501 help
77ef56e4
KS
1502 5-level paging enables access to larger address space:
1503 upto 128 PiB of virtual address space and 4 PiB of
1504 physical address space.
1505
1506 It will be supported by future Intel CPUs.
1507
6657fca0
KS
1508 A kernel with the option enabled can be booted on machines that
1509 support 4- or 5-level paging.
77ef56e4 1510
cb1aaebe 1511 See Documentation/x86/x86_64/5level-paging.rst for more
77ef56e4
KS
1512 information.
1513
1514 Say N if unsure.
1515
10971ab2 1516config X86_DIRECT_GBPAGES
e5008abe 1517 def_bool y
2e1da13f 1518 depends on X86_64
a7f7f624 1519 help
10971ab2
IM
1520 Certain kernel features effectively disable kernel
1521 linear 1 GB mappings (even if the CPU otherwise
1522 supports them), so don't confuse the user by printing
1523 that we have them enabled.
9e899816 1524
5c280cf6
TG
1525config X86_CPA_STATISTICS
1526 bool "Enable statistic for Change Page Attribute"
1527 depends on DEBUG_FS
a7f7f624 1528 help
b75baaf3 1529 Expose statistics about the Change Page Attribute mechanism, which
a943245a 1530 helps to determine the effectiveness of preserving large and huge
5c280cf6
TG
1531 page mappings when mapping protections are changed.
1532
20f07a04
KS
1533config X86_MEM_ENCRYPT
1534 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1535 select DYNAMIC_PHYSICAL_MASK
1536 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
1537 def_bool n
1538
7744ccdb
TL
1539config AMD_MEM_ENCRYPT
1540 bool "AMD Secure Memory Encryption (SME) support"
1541 depends on X86_64 && CPU_SUP_AMD
82fef0ad 1542 select DMA_COHERENT_POOL
ce9084ba 1543 select ARCH_USE_MEMREMAP_PROT
597cfe48 1544 select INSTRUCTION_DECODER
aa5a4611 1545 select ARCH_HAS_CC_PLATFORM
20f07a04 1546 select X86_MEM_ENCRYPT
a7f7f624 1547 help
7744ccdb
TL
1548 Say yes to enable support for the encryption of system memory.
1549 This requires an AMD processor that supports Secure Memory
1550 Encryption (SME).
1551
1552config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1553 bool "Activate AMD Secure Memory Encryption (SME) by default"
7744ccdb 1554 depends on AMD_MEM_ENCRYPT
a7f7f624 1555 help
7744ccdb
TL
1556 Say yes to have system memory encrypted by default if running on
1557 an AMD processor that supports Secure Memory Encryption (SME).
1558
1559 If set to Y, then the encryption of system memory can be
1560 deactivated with the mem_encrypt=off command line option.
1561
1562 If set to N, then the encryption of system memory can be
1563 activated with the mem_encrypt=on command line option.
1564
506f1d07
SR
1565# Common NUMA Features
1566config NUMA
e133f6ea 1567 bool "NUMA Memory Allocation and Scheduler Support"
506f1d07 1568 depends on SMP
b5660ba7
PA
1569 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1570 default y if X86_BIGSMP
7ecd19cf 1571 select USE_PERCPU_NUMA_NODE_ID
a7f7f624 1572 help
e133f6ea 1573 Enable NUMA (Non-Uniform Memory Access) support.
fd51b2d7 1574
506f1d07
SR
1575 The kernel will try to allocate memory used by a CPU on the
1576 local memory controller of the CPU and add some more
1577 NUMA awareness to the kernel.
1578
c280ea5e 1579 For 64-bit this is recommended if the system is Intel Core i7
fd51b2d7
KM
1580 (or later), AMD Opteron, or EM64T NUMA.
1581
b5660ba7 1582 For 32-bit this is only needed if you boot a 32-bit
7cf6c945 1583 kernel on a 64-bit NUMA platform.
fd51b2d7
KM
1584
1585 Otherwise, you should say N.
506f1d07 1586
eec1d4fa 1587config AMD_NUMA
3c2362e6
HH
1588 def_bool y
1589 prompt "Old style AMD Opteron NUMA detection"
5da0ef9a 1590 depends on X86_64 && NUMA && PCI
a7f7f624 1591 help
eec1d4fa
HR
1592 Enable AMD NUMA node topology detection. You should say Y here if
1593 you have a multi processor AMD system. This uses an old method to
1594 read the NUMA configuration directly from the builtin Northbridge
1595 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1596 which also takes priority if both are compiled in.
506f1d07
SR
1597
1598config X86_64_ACPI_NUMA
3c2362e6
HH
1599 def_bool y
1600 prompt "ACPI NUMA detection"
506f1d07
SR
1601 depends on X86_64 && NUMA && ACPI && PCI
1602 select ACPI_NUMA
a7f7f624 1603 help
506f1d07
SR
1604 Enable ACPI SRAT based node topology detection.
1605
1606config NUMA_EMU
1607 bool "NUMA emulation"
1b7e03ef 1608 depends on NUMA
a7f7f624 1609 help
506f1d07
SR
1610 Enable NUMA emulation. A flat machine will be split
1611 into virtual nodes when booted with "numa=fake=N", where N is the
1612 number of nodes. This is only useful for debugging.
1613
1614config NODES_SHIFT
d25e26b6 1615 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
51591e31
DR
1616 range 1 10
1617 default "10" if MAXSMP
506f1d07 1618 default "6" if X86_64
506f1d07 1619 default "3"
a9ee6cf5 1620 depends on NUMA
a7f7f624 1621 help
1184dc2f 1622 Specify the maximum number of NUMA Nodes available on the target
692105b8 1623 system. Increases memory reserved to accommodate various tables.
506f1d07 1624
506f1d07
SR
1625config ARCH_FLATMEM_ENABLE
1626 def_bool y
3b16651f 1627 depends on X86_32 && !NUMA
506f1d07 1628
506f1d07
SR
1629config ARCH_SPARSEMEM_ENABLE
1630 def_bool y
6ea30386 1631 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
506f1d07
SR
1632 select SPARSEMEM_STATIC if X86_32
1633 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1634
3b16651f 1635config ARCH_SPARSEMEM_DEFAULT
6ad57f7f 1636 def_bool X86_64 || (NUMA && X86_32)
3b16651f 1637
506f1d07
SR
1638config ARCH_SELECT_MEMORY_MODEL
1639 def_bool y
b263295d 1640 depends on ARCH_SPARSEMEM_ENABLE
506f1d07
SR
1641
1642config ARCH_MEMORY_PROBE
a0842b70 1643 bool "Enable sysfs memory/probe interface"
5c11f00b 1644 depends on MEMORY_HOTPLUG
a0842b70
TK
1645 help
1646 This option enables a sysfs memory/probe interface for testing.
cb1aaebe 1647 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
a0842b70 1648 If you are unsure how to answer this question, answer N.
506f1d07 1649
3b16651f
TH
1650config ARCH_PROC_KCORE_TEXT
1651 def_bool y
1652 depends on X86_64 && PROC_KCORE
1653
a29815a3 1654config ILLEGAL_POINTER_VALUE
b03b016f
KK
1655 hex
1656 default 0 if X86_32
1657 default 0xdead000000000000 if X86_64
a29815a3 1658
7a67832c
DW
1659config X86_PMEM_LEGACY_DEVICE
1660 bool
1661
ec776ef6 1662config X86_PMEM_LEGACY
7a67832c 1663 tristate "Support non-standard NVDIMMs and ADR protected memory"
9f53f9fa
DW
1664 depends on PHYS_ADDR_T_64BIT
1665 depends on BLK_DEV
7a67832c 1666 select X86_PMEM_LEGACY_DEVICE
7b27a862 1667 select NUMA_KEEP_MEMINFO if NUMA
9f53f9fa 1668 select LIBNVDIMM
ec776ef6
CH
1669 help
1670 Treat memory marked using the non-standard e820 type of 12 as used
1671 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1672 The kernel will offer these regions to the 'pmem' driver so
1673 they can be used for persistent storage.
1674
1675 Say Y if unsure.
1676
506f1d07
SR
1677config HIGHPTE
1678 bool "Allocate 3rd-level pagetables from highmem"
6fc108a0 1679 depends on HIGHMEM
a7f7f624 1680 help
506f1d07
SR
1681 The VM uses one page table entry for each page of physical memory.
1682 For systems with a lot of RAM, this can be wasteful of precious
1683 low memory. Setting this option will put user-space page table
1684 entries in high memory.
1685
9f077871 1686config X86_CHECK_BIOS_CORRUPTION
8f9ca475 1687 bool "Check for low memory corruption"
a7f7f624 1688 help
8f9ca475
IM
1689 Periodically check for memory corruption in low memory, which
1690 is suspected to be caused by BIOS. Even when enabled in the
1691 configuration, it is disabled at runtime. Enable it by
1692 setting "memory_corruption_check=1" on the kernel command
1693 line. By default it scans the low 64k of memory every 60
1694 seconds; see the memory_corruption_check_size and
1695 memory_corruption_check_period parameters in
8c27ceff 1696 Documentation/admin-guide/kernel-parameters.rst to adjust this.
8f9ca475
IM
1697
1698 When enabled with the default parameters, this option has
1699 almost no overhead, as it reserves a relatively small amount
1700 of memory and scans it infrequently. It both detects corruption
1701 and prevents it from affecting the running system.
1702
1703 It is, however, intended as a diagnostic tool; if repeatable
1704 BIOS-originated corruption always affects the same memory,
1705 you can use memmap= to prevent the kernel from using that
1706 memory.
9f077871 1707
c885df50 1708config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
8f9ca475 1709 bool "Set the default setting of memory_corruption_check"
c885df50
JF
1710 depends on X86_CHECK_BIOS_CORRUPTION
1711 default y
a7f7f624 1712 help
8f9ca475
IM
1713 Set whether the default state of memory_corruption_check is
1714 on or off.
c885df50 1715
506f1d07
SR
1716config MATH_EMULATION
1717 bool
a5b9e5a2 1718 depends on MODIFY_LDT_SYSCALL
87d6021b 1719 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
a7f7f624 1720 help
506f1d07
SR
1721 Linux can emulate a math coprocessor (used for floating point
1722 operations) if you don't have one. 486DX and Pentium processors have
1723 a math coprocessor built in, 486SX and 386 do not, unless you added
1724 a 487DX or 387, respectively. (The messages during boot time can
1725 give you some hints here ["man dmesg"].) Everyone needs either a
1726 coprocessor or this emulation.
1727
1728 If you don't have a math coprocessor, you need to say Y here; if you
1729 say Y here even though you have a coprocessor, the coprocessor will
1730 be used nevertheless. (This behavior can be changed with the kernel
1731 command line option "no387", which comes handy if your coprocessor
1732 is broken. Try "man bootparam" or see the documentation of your boot
1733 loader (lilo or loadlin) about how to pass options to the kernel at
1734 boot time.) This means that it is a good idea to say Y here if you
1735 intend to use this kernel on different machines.
1736
1737 More information about the internals of the Linux math coprocessor
1738 emulation can be found in <file:arch/x86/math-emu/README>.
1739
1740 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1741 kernel, it won't hurt.
1742
1743config MTRR
6fc108a0 1744 def_bool y
6a108a14 1745 prompt "MTRR (Memory Type Range Register) support" if EXPERT
a7f7f624 1746 help
506f1d07
SR
1747 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1748 the Memory Type Range Registers (MTRRs) may be used to control
1749 processor access to memory ranges. This is most useful if you have
1750 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1751 allows bus write transfers to be combined into a larger transfer
1752 before bursting over the PCI/AGP bus. This can increase performance
1753 of image write operations 2.5 times or more. Saying Y here creates a
1754 /proc/mtrr file which may be used to manipulate your processor's
1755 MTRRs. Typically the X server should use this.
1756
1757 This code has a reasonably generic interface so that similar
1758 control registers on other processors can be easily supported
1759 as well:
1760
1761 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1762 Registers (ARRs) which provide a similar functionality to MTRRs. For
1763 these, the ARRs are used to emulate the MTRRs.
1764 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1765 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1766 write-combining. All of these processors are supported by this code
1767 and it makes sense to say Y here if you have one of them.
1768
1769 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1770 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1771 can lead to all sorts of problems, so it's good to say Y here.
1772
1773 You can safely say Y even if your machine doesn't have MTRRs, you'll
1774 just add about 9 KB to your kernel.
1775
cb1aaebe 1776 See <file:Documentation/x86/mtrr.rst> for more information.
506f1d07 1777
95ffa243 1778config MTRR_SANITIZER
2ffb3501 1779 def_bool y
95ffa243
YL
1780 prompt "MTRR cleanup support"
1781 depends on MTRR
a7f7f624 1782 help
aba3728c
TG
1783 Convert MTRR layout from continuous to discrete, so X drivers can
1784 add writeback entries.
95ffa243 1785
aba3728c 1786 Can be disabled with disable_mtrr_cleanup on the kernel command line.
692105b8 1787 The largest mtrr entry size for a continuous block can be set with
aba3728c 1788 mtrr_chunk_size.
95ffa243 1789
2ffb3501 1790 If unsure, say Y.
95ffa243
YL
1791
1792config MTRR_SANITIZER_ENABLE_DEFAULT
f5098d62
YL
1793 int "MTRR cleanup enable value (0-1)"
1794 range 0 1
1795 default "0"
95ffa243 1796 depends on MTRR_SANITIZER
a7f7f624 1797 help
f5098d62 1798 Enable mtrr cleanup default value
95ffa243 1799
12031a62
YL
1800config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1801 int "MTRR cleanup spare reg num (0-7)"
1802 range 0 7
1803 default "1"
1804 depends on MTRR_SANITIZER
a7f7f624 1805 help
12031a62 1806 mtrr cleanup spare entries default, it can be changed via
aba3728c 1807 mtrr_spare_reg_nr=N on the kernel command line.
12031a62 1808
2e5d9c85 1809config X86_PAT
6fc108a0 1810 def_bool y
6a108a14 1811 prompt "x86 PAT support" if EXPERT
2a8a2719 1812 depends on MTRR
a7f7f624 1813 help
2e5d9c85 1814 Use PAT attributes to setup page level cache control.
042b78e4 1815
2e5d9c85 1816 PATs are the modern equivalents of MTRRs and are much more
1817 flexible than MTRRs.
1818
1819 Say N here if you see bootup problems (boot crash, boot hang,
042b78e4 1820 spontaneous reboots) or a non-working video driver.
2e5d9c85 1821
1822 If unsure, say Y.
1823
46cf98cd
VP
1824config ARCH_USES_PG_UNCACHED
1825 def_bool y
1826 depends on X86_PAT
1827
628c6246
PA
1828config ARCH_RANDOM
1829 def_bool y
1830 prompt "x86 architectural random number generator" if EXPERT
a7f7f624 1831 help
628c6246
PA
1832 Enable the x86 architectural RDRAND instruction
1833 (Intel Bull Mountain technology) to generate random numbers.
1834 If supported, this is a high bandwidth, cryptographically
1835 secure hardware random number generator.
1836
51ae4a2d
PA
1837config X86_SMAP
1838 def_bool y
1839 prompt "Supervisor Mode Access Prevention" if EXPERT
a7f7f624 1840 help
51ae4a2d
PA
1841 Supervisor Mode Access Prevention (SMAP) is a security
1842 feature in newer Intel processors. There is a small
1843 performance cost if this enabled and turned on; there is
1844 also a small increase in the kernel size if this is enabled.
1845
1846 If unsure, say Y.
1847
b971880f 1848config X86_UMIP
796ebc81 1849 def_bool y
b971880f 1850 prompt "User Mode Instruction Prevention" if EXPERT
a7f7f624 1851 help
b971880f
BM
1852 User Mode Instruction Prevention (UMIP) is a security feature in
1853 some x86 processors. If enabled, a general protection fault is
1854 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1855 executed in user mode. These instructions unnecessarily expose
1856 information about the hardware state.
796ebc81
RN
1857
1858 The vast majority of applications do not use these instructions.
1859 For the very few that do, software emulation is provided in
1860 specific cases in protected and virtual-8086 modes. Emulated
1861 results are dummy.
aa35f896 1862
35e97790 1863config X86_INTEL_MEMORY_PROTECTION_KEYS
38f3e775 1864 prompt "Memory Protection Keys"
35e97790 1865 def_bool y
284244a9 1866 # Note: only available in 64-bit mode
38f3e775 1867 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
52c8e601
IM
1868 select ARCH_USES_HIGH_VMA_FLAGS
1869 select ARCH_HAS_PKEYS
a7f7f624 1870 help
284244a9
DH
1871 Memory Protection Keys provides a mechanism for enforcing
1872 page-based protections, but without requiring modification of the
1873 page tables when an application changes protection domains.
1874
1eecbcdc 1875 For details, see Documentation/core-api/protection-keys.rst
284244a9
DH
1876
1877 If unsure, say y.
35e97790 1878
db616173
MH
1879choice
1880 prompt "TSX enable mode"
1881 depends on CPU_SUP_INTEL
1882 default X86_INTEL_TSX_MODE_OFF
1883 help
1884 Intel's TSX (Transactional Synchronization Extensions) feature
1885 allows to optimize locking protocols through lock elision which
1886 can lead to a noticeable performance boost.
1887
1888 On the other hand it has been shown that TSX can be exploited
1889 to form side channel attacks (e.g. TAA) and chances are there
1890 will be more of those attacks discovered in the future.
1891
1892 Therefore TSX is not enabled by default (aka tsx=off). An admin
1893 might override this decision by tsx=on the command line parameter.
1894 Even with TSX enabled, the kernel will attempt to enable the best
1895 possible TAA mitigation setting depending on the microcode available
1896 for the particular machine.
1897
1898 This option allows to set the default tsx mode between tsx=on, =off
1899 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1900 details.
1901
1902 Say off if not sure, auto if TSX is in use but it should be used on safe
1903 platforms or on if TSX is in use and the security aspect of tsx is not
1904 relevant.
1905
1906config X86_INTEL_TSX_MODE_OFF
1907 bool "off"
1908 help
1909 TSX is disabled if possible - equals to tsx=off command line parameter.
1910
1911config X86_INTEL_TSX_MODE_ON
1912 bool "on"
1913 help
1914 TSX is always enabled on TSX capable HW - equals the tsx=on command
1915 line parameter.
1916
1917config X86_INTEL_TSX_MODE_AUTO
1918 bool "auto"
1919 help
1920 TSX is enabled on TSX capable HW that is believed to be safe against
1921 side channel attacks- equals the tsx=auto command line parameter.
1922endchoice
1923
e7e05452
SC
1924config X86_SGX
1925 bool "Software Guard eXtensions (SGX)"
1926 depends on X86_64 && CPU_SUP_INTEL
1927 depends on CRYPTO=y
1928 depends on CRYPTO_SHA256=y
1929 select SRCU
1930 select MMU_NOTIFIER
901ddbb9 1931 select NUMA_KEEP_MEMINFO if NUMA
40e0e784 1932 select XARRAY_MULTI
e7e05452
SC
1933 help
1934 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1935 that can be used by applications to set aside private regions of code
1936 and data, referred to as enclaves. An enclave's private memory can
1937 only be accessed by code running within the enclave. Accesses from
1938 outside the enclave, including other enclaves, are disallowed by
1939 hardware.
1940
1941 If unsure, say N.
1942
506f1d07 1943config EFI
9ba16087 1944 bool "EFI runtime service support"
5b83683f 1945 depends on ACPI
f6ce5002 1946 select UCS2_STRING
022ee6c5 1947 select EFI_RUNTIME_WRAPPERS
1ff2fc02 1948 select ARCH_USE_MEMREMAP_PROT
a7f7f624 1949 help
8f9ca475
IM
1950 This enables the kernel to use EFI runtime services that are
1951 available (such as the EFI variable services).
506f1d07 1952
8f9ca475
IM
1953 This option is only useful on systems that have EFI firmware.
1954 In addition, you should use the latest ELILO loader available
1955 at <http://elilo.sourceforge.net> in order to take advantage
1956 of EFI runtime services. However, even with this option, the
1957 resultant kernel should continue to boot on existing non-EFI
1958 platforms.
506f1d07 1959
291f3632 1960config EFI_STUB
8f24f8c2 1961 bool "EFI stub support"
c6dbd3e5 1962 depends on EFI
8f24f8c2
AB
1963 depends on $(cc-option,-mabi=ms) || X86_32
1964 select RELOCATABLE
a7f7f624 1965 help
8f24f8c2 1966 This kernel feature allows a bzImage to be loaded directly
291f3632
MF
1967 by EFI firmware without the use of a bootloader.
1968
4f4cfa6c 1969 See Documentation/admin-guide/efi-stub.rst for more information.
0c759662 1970
7d453eee
MF
1971config EFI_MIXED
1972 bool "EFI mixed-mode support"
1973 depends on EFI_STUB && X86_64
a7f7f624 1974 help
7d453eee
MF
1975 Enabling this feature allows a 64-bit kernel to be booted
1976 on a 32-bit firmware, provided that your CPU supports 64-bit
1977 mode.
1978
1979 Note that it is not possible to boot a mixed-mode enabled
1980 kernel via the EFI boot stub - a bootloader that supports
1981 the EFI handover protocol must be used.
1982
1983 If unsure, say N.
1984
8636a1f9 1985source "kernel/Kconfig.hz"
506f1d07
SR
1986
1987config KEXEC
1988 bool "kexec system call"
2965faa5 1989 select KEXEC_CORE
a7f7f624 1990 help
506f1d07
SR
1991 kexec is a system call that implements the ability to shutdown your
1992 current kernel, and to start another kernel. It is like a reboot
1993 but it is independent of the system firmware. And like a reboot
1994 you can start any kernel with it, not just Linux.
1995
1996 The name comes from the similarity to the exec system call.
1997
1998 It is an ongoing process to be certain the hardware in a machine
1999 is properly shutdown, so do not be surprised if this code does not
bf220695
GU
2000 initially work for you. As of this writing the exact hardware
2001 interface is strongly in flux, so no good recommendation can be
2002 made.
506f1d07 2003
74ca317c
VG
2004config KEXEC_FILE
2005 bool "kexec file based system call"
2965faa5 2006 select KEXEC_CORE
74ca317c 2007 select BUILD_BIN2C
74ca317c
VG
2008 depends on X86_64
2009 depends on CRYPTO=y
2010 depends on CRYPTO_SHA256=y
a7f7f624 2011 help
74ca317c
VG
2012 This is new version of kexec system call. This system call is
2013 file based and takes file descriptors as system call argument
2014 for kernel and initramfs as opposed to list of segments as
2015 accepted by previous system call.
2016
b799a09f
AT
2017config ARCH_HAS_KEXEC_PURGATORY
2018 def_bool KEXEC_FILE
2019
99d5cadf 2020config KEXEC_SIG
8e7d8381 2021 bool "Verify kernel signature during kexec_file_load() syscall"
74ca317c 2022 depends on KEXEC_FILE
a7f7f624 2023 help
d8eb8940 2024
99d5cadf
JB
2025 This option makes the kexec_file_load() syscall check for a valid
2026 signature of the kernel image. The image can still be loaded without
2027 a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2028 there's a signature that we can check, then it must be valid.
2029
2030 In addition to this option, you need to enable signature
d8eb8940
BP
2031 verification for the corresponding kernel image type being
2032 loaded in order for this to work.
8e7d8381 2033
99d5cadf
JB
2034config KEXEC_SIG_FORCE
2035 bool "Require a valid signature in kexec_file_load() syscall"
2036 depends on KEXEC_SIG
a7f7f624 2037 help
99d5cadf
JB
2038 This option makes kernel signature verification mandatory for
2039 the kexec_file_load() syscall.
2040
8e7d8381
VG
2041config KEXEC_BZIMAGE_VERIFY_SIG
2042 bool "Enable bzImage signature verification support"
99d5cadf 2043 depends on KEXEC_SIG
8e7d8381
VG
2044 depends on SIGNED_PE_FILE_VERIFICATION
2045 select SYSTEM_TRUSTED_KEYRING
a7f7f624 2046 help
8e7d8381
VG
2047 Enable bzImage signature verification support.
2048
506f1d07 2049config CRASH_DUMP
04b69447 2050 bool "kernel crash dumps"
506f1d07 2051 depends on X86_64 || (X86_32 && HIGHMEM)
a7f7f624 2052 help
506f1d07
SR
2053 Generate crash dump after being started by kexec.
2054 This should be normally only set in special crash dump kernels
2055 which are loaded in the main kernel with kexec-tools into
2056 a specially reserved region and then later executed after
2057 a crash by kdump/kexec. The crash dump kernel must be compiled
2058 to a memory address not used by the main kernel or BIOS using
2059 PHYSICAL_START, or it must be built as a relocatable image
2060 (CONFIG_RELOCATABLE=y).
330d4810 2061 For more details see Documentation/admin-guide/kdump/kdump.rst
506f1d07 2062
3ab83521 2063config KEXEC_JUMP
6ea30386 2064 bool "kexec jump"
fee7b0d8 2065 depends on KEXEC && HIBERNATION
a7f7f624 2066 help
89081d17
HY
2067 Jump between original kernel and kexeced kernel and invoke
2068 code in physical address mode via KEXEC
3ab83521 2069
506f1d07 2070config PHYSICAL_START
6a108a14 2071 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
ceefccc9 2072 default "0x1000000"
a7f7f624 2073 help
506f1d07
SR
2074 This gives the physical address where the kernel is loaded.
2075
2076 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2077 bzImage will decompress itself to above physical address and
2078 run from there. Otherwise, bzImage will run from the address where
2079 it has been loaded by the boot loader and will ignore above physical
2080 address.
2081
2082 In normal kdump cases one does not have to set/change this option
2083 as now bzImage can be compiled as a completely relocatable image
2084 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2085 address. This option is mainly useful for the folks who don't want
2086 to use a bzImage for capturing the crash dump and want to use a
2087 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2088 to be specifically compiled to run from a specific memory area
2089 (normally a reserved region) and this option comes handy.
2090
ceefccc9
PA
2091 So if you are using bzImage for capturing the crash dump,
2092 leave the value here unchanged to 0x1000000 and set
2093 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2094 for capturing the crash dump change this value to start of
2095 the reserved region. In other words, it can be set based on
2096 the "X" value as specified in the "crashkernel=YM@XM"
2097 command line boot parameter passed to the panic-ed
330d4810 2098 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
ceefccc9 2099 for more details about crash dumps.
506f1d07
SR
2100
2101 Usage of bzImage for capturing the crash dump is recommended as
2102 one does not have to build two kernels. Same kernel can be used
2103 as production kernel and capture kernel. Above option should have
2104 gone away after relocatable bzImage support is introduced. But it
2105 is present because there are users out there who continue to use
2106 vmlinux for dump capture. This option should go away down the
2107 line.
2108
2109 Don't change this unless you know what you are doing.
2110
2111config RELOCATABLE
26717808
PA
2112 bool "Build a relocatable kernel"
2113 default y
a7f7f624 2114 help
506f1d07
SR
2115 This builds a kernel image that retains relocation information
2116 so it can be loaded someplace besides the default 1MB.
2117 The relocations tend to make the kernel binary about 10% larger,
2118 but are discarded at runtime.
2119
2120 One use is for the kexec on panic case where the recovery kernel
2121 must live at a different physical address than the primary
2122 kernel.
2123
2124 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2125 it has been loaded at and the compile time physical address
8ab3820f 2126 (CONFIG_PHYSICAL_START) is used as the minimum location.
506f1d07 2127
8ab3820f 2128config RANDOMIZE_BASE
e8581e3d 2129 bool "Randomize the address of the kernel image (KASLR)"
8ab3820f 2130 depends on RELOCATABLE
6807c846 2131 default y
a7f7f624 2132 help
e8581e3d
BH
2133 In support of Kernel Address Space Layout Randomization (KASLR),
2134 this randomizes the physical address at which the kernel image
2135 is decompressed and the virtual address where the kernel
2136 image is mapped, as a security feature that deters exploit
2137 attempts relying on knowledge of the location of kernel
2138 code internals.
2139
ed9f007e
KC
2140 On 64-bit, the kernel physical and virtual addresses are
2141 randomized separately. The physical address will be anywhere
2142 between 16MB and the top of physical memory (up to 64TB). The
2143 virtual address will be randomized from 16MB up to 1GB (9 bits
2144 of entropy). Note that this also reduces the memory space
2145 available to kernel modules from 1.5GB to 1GB.
2146
2147 On 32-bit, the kernel physical and virtual addresses are
2148 randomized together. They will be randomized from 16MB up to
2149 512MB (8 bits of entropy).
e8581e3d
BH
2150
2151 Entropy is generated using the RDRAND instruction if it is
2152 supported. If RDTSC is supported, its value is mixed into
2153 the entropy pool as well. If neither RDRAND nor RDTSC are
ed9f007e
KC
2154 supported, then entropy is read from the i8254 timer. The
2155 usable entropy is limited by the kernel being built using
2156 2GB addressing, and that PHYSICAL_ALIGN must be at a
2157 minimum of 2MB. As a result, only 10 bits of entropy are
2158 theoretically possible, but the implementations are further
2159 limited due to memory layouts.
e8581e3d 2160
6807c846 2161 If unsure, say Y.
8ab3820f
KC
2162
2163# Relocation on x86 needs some additional build support
845adf72
PA
2164config X86_NEED_RELOCS
2165 def_bool y
8ab3820f 2166 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
845adf72 2167
506f1d07 2168config PHYSICAL_ALIGN
a0215061 2169 hex "Alignment value to which kernel should be aligned"
8ab3820f 2170 default "0x200000"
a0215061
KC
2171 range 0x2000 0x1000000 if X86_32
2172 range 0x200000 0x1000000 if X86_64
a7f7f624 2173 help
506f1d07
SR
2174 This value puts the alignment restrictions on physical address
2175 where kernel is loaded and run from. Kernel is compiled for an
2176 address which meets above alignment restriction.
2177
2178 If bootloader loads the kernel at a non-aligned address and
2179 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2180 address aligned to above value and run from there.
2181
2182 If bootloader loads the kernel at a non-aligned address and
2183 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2184 load address and decompress itself to the address it has been
2185 compiled for and run from there. The address for which kernel is
2186 compiled already meets above alignment restrictions. Hence the
2187 end result is that kernel runs from a physical address meeting
2188 above alignment restrictions.
2189
a0215061
KC
2190 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2191 this value must be a multiple of 0x200000.
2192
506f1d07
SR
2193 Don't change this unless you know what you are doing.
2194
eedb92ab
KS
2195config DYNAMIC_MEMORY_LAYOUT
2196 bool
a7f7f624 2197 help
eedb92ab
KS
2198 This option makes base addresses of vmalloc and vmemmap as well as
2199 __PAGE_OFFSET movable during boot.
2200
0483e1fa
TG
2201config RANDOMIZE_MEMORY
2202 bool "Randomize the kernel memory sections"
2203 depends on X86_64
2204 depends on RANDOMIZE_BASE
eedb92ab 2205 select DYNAMIC_MEMORY_LAYOUT
0483e1fa 2206 default RANDOMIZE_BASE
a7f7f624 2207 help
0483e1fa
TG
2208 Randomizes the base virtual address of kernel memory sections
2209 (physical memory mapping, vmalloc & vmemmap). This security feature
2210 makes exploits relying on predictable memory locations less reliable.
2211
2212 The order of allocations remains unchanged. Entropy is generated in
2213 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2214 configuration have in average 30,000 different possible virtual
2215 addresses for each memory section.
2216
6807c846 2217 If unsure, say Y.
0483e1fa 2218
90397a41
TG
2219config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2220 hex "Physical memory mapping padding" if EXPERT
2221 depends on RANDOMIZE_MEMORY
2222 default "0xa" if MEMORY_HOTPLUG
2223 default "0x0"
2224 range 0x1 0x40 if MEMORY_HOTPLUG
2225 range 0x0 0x40
a7f7f624 2226 help
90397a41
TG
2227 Define the padding in terabytes added to the existing physical
2228 memory size during kernel memory randomization. It is useful
2229 for memory hotplug support but reduces the entropy available for
2230 address randomization.
2231
2232 If unsure, leave at the default value.
2233
506f1d07 2234config HOTPLUG_CPU
bebd024e 2235 def_bool y
40b31360 2236 depends on SMP
506f1d07 2237
80aa1dff
FY
2238config BOOTPARAM_HOTPLUG_CPU0
2239 bool "Set default setting of cpu0_hotpluggable"
2c922cd0 2240 depends on HOTPLUG_CPU
a7f7f624 2241 help
80aa1dff
FY
2242 Set whether default state of cpu0_hotpluggable is on or off.
2243
2244 Say Y here to enable CPU0 hotplug by default. If this switch
2245 is turned on, there is no need to give cpu0_hotplug kernel
2246 parameter and the CPU0 hotplug feature is enabled by default.
2247
2248 Please note: there are two known CPU0 dependencies if you want
2249 to enable the CPU0 hotplug feature either by this switch or by
2250 cpu0_hotplug kernel parameter.
2251
2252 First, resume from hibernate or suspend always starts from CPU0.
2253 So hibernate and suspend are prevented if CPU0 is offline.
2254
2255 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2256 offline if any interrupt can not migrate out of CPU0. There may
2257 be other CPU0 dependencies.
2258
2259 Please make sure the dependencies are under your control before
2260 you enable this feature.
2261
2262 Say N if you don't want to enable CPU0 hotplug feature by default.
2263 You still can enable the CPU0 hotplug feature at boot by kernel
2264 parameter cpu0_hotplug.
2265
a71c8bc5
FY
2266config DEBUG_HOTPLUG_CPU0
2267 def_bool n
2268 prompt "Debug CPU0 hotplug"
2c922cd0 2269 depends on HOTPLUG_CPU
a7f7f624 2270 help
a71c8bc5
FY
2271 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2272 soon as possible and boots up userspace with CPU0 offlined. User
2273 can online CPU0 back after boot time.
2274
2275 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2276 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2277 compilation or giving cpu0_hotplug kernel parameter at boot.
2278
2279 If unsure, say N.
2280
506f1d07 2281config COMPAT_VDSO
b0b49f26
AL
2282 def_bool n
2283 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
953fee1d 2284 depends on COMPAT_32
a7f7f624 2285 help
b0b49f26
AL
2286 Certain buggy versions of glibc will crash if they are
2287 presented with a 32-bit vDSO that is not mapped at the address
2288 indicated in its segment table.
e84446de 2289
b0b49f26
AL
2290 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2291 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2292 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2293 the only released version with the bug, but OpenSUSE 9
2294 contains a buggy "glibc 2.3.2".
506f1d07 2295
b0b49f26
AL
2296 The symptom of the bug is that everything crashes on startup, saying:
2297 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2298
2299 Saying Y here changes the default value of the vdso32 boot
2300 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2301 This works around the glibc bug but hurts performance.
2302
2303 If unsure, say N: if you are compiling your own kernel, you
2304 are unlikely to be using a buggy version of glibc.
506f1d07 2305
3dc33bd3
KC
2306choice
2307 prompt "vsyscall table for legacy applications"
2308 depends on X86_64
625b7b7f 2309 default LEGACY_VSYSCALL_XONLY
3dc33bd3
KC
2310 help
2311 Legacy user code that does not know how to find the vDSO expects
2312 to be able to issue three syscalls by calling fixed addresses in
2313 kernel space. Since this location is not randomized with ASLR,
2314 it can be used to assist security vulnerability exploitation.
2315
2316 This setting can be changed at boot time via the kernel command
bd49e16e 2317 line parameter vsyscall=[emulate|xonly|none].
3dc33bd3
KC
2318
2319 On a system with recent enough glibc (2.14 or newer) and no
2320 static binaries, you can say None without a performance penalty
2321 to improve security.
2322
bd49e16e 2323 If unsure, select "Emulate execution only".
3dc33bd3 2324
3dc33bd3 2325 config LEGACY_VSYSCALL_EMULATE
bd49e16e 2326 bool "Full emulation"
3dc33bd3 2327 help
bd49e16e
AL
2328 The kernel traps and emulates calls into the fixed vsyscall
2329 address mapping. This makes the mapping non-executable, but
2330 it still contains readable known contents, which could be
2331 used in certain rare security vulnerability exploits. This
2332 configuration is recommended when using legacy userspace
2333 that still uses vsyscalls along with legacy binary
2334 instrumentation tools that require code to be readable.
2335
2336 An example of this type of legacy userspace is running
2337 Pin on an old binary that still uses vsyscalls.
2338
2339 config LEGACY_VSYSCALL_XONLY
2340 bool "Emulate execution only"
2341 help
2342 The kernel traps and emulates calls into the fixed vsyscall
2343 address mapping and does not allow reads. This
2344 configuration is recommended when userspace might use the
2345 legacy vsyscall area but support for legacy binary
2346 instrumentation of legacy code is not needed. It mitigates
2347 certain uses of the vsyscall area as an ASLR-bypassing
2348 buffer.
3dc33bd3
KC
2349
2350 config LEGACY_VSYSCALL_NONE
2351 bool "None"
2352 help
2353 There will be no vsyscall mapping at all. This will
2354 eliminate any risk of ASLR bypass due to the vsyscall
2355 fixed address mapping. Attempts to use the vsyscalls
2356 will be reported to dmesg, so that either old or
2357 malicious userspace programs can be identified.
2358
2359endchoice
2360
516cbf37
TB
2361config CMDLINE_BOOL
2362 bool "Built-in kernel command line"
a7f7f624 2363 help
516cbf37
TB
2364 Allow for specifying boot arguments to the kernel at
2365 build time. On some systems (e.g. embedded ones), it is
2366 necessary or convenient to provide some or all of the
2367 kernel boot arguments with the kernel itself (that is,
2368 to not rely on the boot loader to provide them.)
2369
2370 To compile command line arguments into the kernel,
2371 set this option to 'Y', then fill in the
69711ca1 2372 boot arguments in CONFIG_CMDLINE.
516cbf37
TB
2373
2374 Systems with fully functional boot loaders (i.e. non-embedded)
2375 should leave this option set to 'N'.
2376
2377config CMDLINE
2378 string "Built-in kernel command string"
2379 depends on CMDLINE_BOOL
2380 default ""
a7f7f624 2381 help
516cbf37
TB
2382 Enter arguments here that should be compiled into the kernel
2383 image and used at boot time. If the boot loader provides a
2384 command line at boot time, it is appended to this string to
2385 form the full kernel command line, when the system boots.
2386
2387 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2388 change this behavior.
2389
2390 In most cases, the command line (whether built-in or provided
2391 by the boot loader) should specify the device for the root
2392 file system.
2393
2394config CMDLINE_OVERRIDE
2395 bool "Built-in command line overrides boot loader arguments"
645e6466 2396 depends on CMDLINE_BOOL && CMDLINE != ""
a7f7f624 2397 help
516cbf37
TB
2398 Set this option to 'Y' to have the kernel ignore the boot loader
2399 command line, and use ONLY the built-in command line.
2400
2401 This is used to work around broken boot loaders. This should
2402 be set to 'N' under normal conditions.
2403
a5b9e5a2
AL
2404config MODIFY_LDT_SYSCALL
2405 bool "Enable the LDT (local descriptor table)" if EXPERT
2406 default y
a7f7f624 2407 help
a5b9e5a2
AL
2408 Linux can allow user programs to install a per-process x86
2409 Local Descriptor Table (LDT) using the modify_ldt(2) system
2410 call. This is required to run 16-bit or segmented code such as
2411 DOSEMU or some Wine programs. It is also used by some very old
2412 threading libraries.
2413
2414 Enabling this feature adds a small amount of overhead to
2415 context switches and increases the low-level kernel attack
2416 surface. Disabling it removes the modify_ldt(2) system call.
2417
2418 Saying 'N' here may make sense for embedded or server kernels.
2419
3aac3ebe
TG
2420config STRICT_SIGALTSTACK_SIZE
2421 bool "Enforce strict size checking for sigaltstack"
2422 depends on DYNAMIC_SIGFRAME
2423 help
2424 For historical reasons MINSIGSTKSZ is a constant which became
2425 already too small with AVX512 support. Add a mechanism to
2426 enforce strict checking of the sigaltstack size against the
2427 real size of the FPU frame. This option enables the check
2428 by default. It can also be controlled via the kernel command
2429 line option 'strict_sas_size' independent of this config
2430 switch. Enabling it might break existing applications which
2431 allocate a too small sigaltstack but 'work' because they
2432 never get a signal delivered.
2433
2434 Say 'N' unless you want to really enforce this check.
2435
b700e7f0
SJ
2436source "kernel/livepatch/Kconfig"
2437
506f1d07
SR
2438endmenu
2439
3072e413
MH
2440config ARCH_HAS_ADD_PAGES
2441 def_bool y
5c11f00b 2442 depends on ARCH_ENABLE_MEMORY_HOTPLUG
3072e413 2443
f91ef222
OS
2444config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2445 def_bool y
2446
da85f865 2447menu "Power management and ACPI options"
e279b6c1
SR
2448
2449config ARCH_HIBERNATION_HEADER
3c2362e6 2450 def_bool y
44556530 2451 depends on HIBERNATION
e279b6c1
SR
2452
2453source "kernel/power/Kconfig"
2454
2455source "drivers/acpi/Kconfig"
2456
a6b68076 2457config X86_APM_BOOT
6fc108a0 2458 def_bool y
282e5aab 2459 depends on APM
a6b68076 2460
e279b6c1
SR
2461menuconfig APM
2462 tristate "APM (Advanced Power Management) BIOS support"
efefa6f6 2463 depends on X86_32 && PM_SLEEP
a7f7f624 2464 help
e279b6c1
SR
2465 APM is a BIOS specification for saving power using several different
2466 techniques. This is mostly useful for battery powered laptops with
2467 APM compliant BIOSes. If you say Y here, the system time will be
2468 reset after a RESUME operation, the /proc/apm device will provide
2469 battery status information, and user-space programs will receive
2470 notification of APM "events" (e.g. battery status change).
2471
2472 If you select "Y" here, you can disable actual use of the APM
2473 BIOS by passing the "apm=off" option to the kernel at boot time.
2474
2475 Note that the APM support is almost completely disabled for
2476 machines with more than one CPU.
2477
2478 In order to use APM, you will need supporting software. For location
151f4e2b 2479 and more information, read <file:Documentation/power/apm-acpi.rst>
2dc98fd3 2480 and the Battery Powered Linux mini-HOWTO, available from
e279b6c1
SR
2481 <http://www.tldp.org/docs.html#howto>.
2482
2483 This driver does not spin down disk drives (see the hdparm(8)
2484 manpage ("man 8 hdparm") for that), and it doesn't turn off
2485 VESA-compliant "green" monitors.
2486
2487 This driver does not support the TI 4000M TravelMate and the ACER
2488 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2489 desktop machines also don't have compliant BIOSes, and this driver
2490 may cause those machines to panic during the boot phase.
2491
2492 Generally, if you don't have a battery in your machine, there isn't
2493 much point in using this driver and you should say N. If you get
2494 random kernel OOPSes or reboots that don't seem to be related to
2495 anything, try disabling/enabling this option (or disabling/enabling
2496 APM in your BIOS).
2497
2498 Some other things you should try when experiencing seemingly random,
2499 "weird" problems:
2500
2501 1) make sure that you have enough swap space and that it is
2502 enabled.
2503 2) pass the "no-hlt" option to the kernel
2504 3) switch on floating point emulation in the kernel and pass
2505 the "no387" option to the kernel
2506 4) pass the "floppy=nodma" option to the kernel
2507 5) pass the "mem=4M" option to the kernel (thereby disabling
2508 all but the first 4 MB of RAM)
2509 6) make sure that the CPU is not over clocked.
2510 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2511 8) disable the cache from your BIOS settings
2512 9) install a fan for the video card or exchange video RAM
2513 10) install a better fan for the CPU
2514 11) exchange RAM chips
2515 12) exchange the motherboard.
2516
2517 To compile this driver as a module, choose M here: the
2518 module will be called apm.
2519
2520if APM
2521
2522config APM_IGNORE_USER_SUSPEND
2523 bool "Ignore USER SUSPEND"
a7f7f624 2524 help
e279b6c1
SR
2525 This option will ignore USER SUSPEND requests. On machines with a
2526 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2527 series notebooks, it is necessary to say Y because of a BIOS bug.
2528
2529config APM_DO_ENABLE
2530 bool "Enable PM at boot time"
a7f7f624 2531 help
e279b6c1
SR
2532 Enable APM features at boot time. From page 36 of the APM BIOS
2533 specification: "When disabled, the APM BIOS does not automatically
2534 power manage devices, enter the Standby State, enter the Suspend
2535 State, or take power saving steps in response to CPU Idle calls."
2536 This driver will make CPU Idle calls when Linux is idle (unless this
2537 feature is turned off -- see "Do CPU IDLE calls", below). This
2538 should always save battery power, but more complicated APM features
2539 will be dependent on your BIOS implementation. You may need to turn
2540 this option off if your computer hangs at boot time when using APM
2541 support, or if it beeps continuously instead of suspending. Turn
2542 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2543 T400CDT. This is off by default since most machines do fine without
2544 this feature.
2545
2546config APM_CPU_IDLE
dd8af076 2547 depends on CPU_IDLE
e279b6c1 2548 bool "Make CPU Idle calls when idle"
a7f7f624 2549 help
e279b6c1
SR
2550 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2551 On some machines, this can activate improved power savings, such as
2552 a slowed CPU clock rate, when the machine is idle. These idle calls
2553 are made after the idle loop has run for some length of time (e.g.,
2554 333 mS). On some machines, this will cause a hang at boot time or
2555 whenever the CPU becomes idle. (On machines with more than one CPU,
2556 this option does nothing.)
2557
2558config APM_DISPLAY_BLANK
2559 bool "Enable console blanking using APM"
a7f7f624 2560 help
e279b6c1
SR
2561 Enable console blanking using the APM. Some laptops can use this to
2562 turn off the LCD backlight when the screen blanker of the Linux
2563 virtual console blanks the screen. Note that this is only used by
2564 the virtual console screen blanker, and won't turn off the backlight
2565 when using the X Window system. This also doesn't have anything to
2566 do with your VESA-compliant power-saving monitor. Further, this
2567 option doesn't work for all laptops -- it might not turn off your
2568 backlight at all, or it might print a lot of errors to the console,
2569 especially if you are using gpm.
2570
2571config APM_ALLOW_INTS
2572 bool "Allow interrupts during APM BIOS calls"
a7f7f624 2573 help
e279b6c1
SR
2574 Normally we disable external interrupts while we are making calls to
2575 the APM BIOS as a measure to lessen the effects of a badly behaving
2576 BIOS implementation. The BIOS should reenable interrupts if it
2577 needs to. Unfortunately, some BIOSes do not -- especially those in
2578 many of the newer IBM Thinkpads. If you experience hangs when you
2579 suspend, try setting this to Y. Otherwise, say N.
2580
e279b6c1
SR
2581endif # APM
2582
bb0a56ec 2583source "drivers/cpufreq/Kconfig"
e279b6c1
SR
2584
2585source "drivers/cpuidle/Kconfig"
2586
27471fdb
AH
2587source "drivers/idle/Kconfig"
2588
e279b6c1
SR
2589endmenu
2590
2591
2592menu "Bus options (PCI etc.)"
2593
e279b6c1
SR
2594choice
2595 prompt "PCI access mode"
efefa6f6 2596 depends on X86_32 && PCI
e279b6c1 2597 default PCI_GOANY
a7f7f624 2598 help
e279b6c1
SR
2599 On PCI systems, the BIOS can be used to detect the PCI devices and
2600 determine their configuration. However, some old PCI motherboards
2601 have BIOS bugs and may crash if this is done. Also, some embedded
2602 PCI-based systems don't have any BIOS at all. Linux can also try to
2603 detect the PCI hardware directly without using the BIOS.
2604
2605 With this option, you can specify how Linux should detect the
2606 PCI devices. If you choose "BIOS", the BIOS will be used,
2607 if you choose "Direct", the BIOS won't be used, and if you
2608 choose "MMConfig", then PCI Express MMCONFIG will be used.
2609 If you choose "Any", the kernel will try MMCONFIG, then the
2610 direct access method and falls back to the BIOS if that doesn't
2611 work. If unsure, go with the default, which is "Any".
2612
2613config PCI_GOBIOS
2614 bool "BIOS"
2615
2616config PCI_GOMMCONFIG
2617 bool "MMConfig"
2618
2619config PCI_GODIRECT
2620 bool "Direct"
2621
3ef0e1f8 2622config PCI_GOOLPC
76fb6570 2623 bool "OLPC XO-1"
3ef0e1f8
AS
2624 depends on OLPC
2625
2bdd1b03
AS
2626config PCI_GOANY
2627 bool "Any"
2628
e279b6c1
SR
2629endchoice
2630
2631config PCI_BIOS
3c2362e6 2632 def_bool y
efefa6f6 2633 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
e279b6c1
SR
2634
2635# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2636config PCI_DIRECT
3c2362e6 2637 def_bool y
0aba496f 2638 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
e279b6c1
SR
2639
2640config PCI_MMCONFIG
b45c9f36
JK
2641 bool "Support mmconfig PCI config space access" if X86_64
2642 default y
4590d98f 2643 depends on PCI && (ACPI || JAILHOUSE_GUEST)
b45c9f36 2644 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
e279b6c1 2645
3ef0e1f8 2646config PCI_OLPC
2bdd1b03
AS
2647 def_bool y
2648 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
3ef0e1f8 2649
b5401a96
AN
2650config PCI_XEN
2651 def_bool y
2652 depends on PCI && XEN
b5401a96 2653
8364e1f8
JK
2654config MMCONF_FAM10H
2655 def_bool y
2656 depends on X86_64 && PCI_MMCONFIG && ACPI
e279b6c1 2657
3f6ea84a 2658config PCI_CNB20LE_QUIRK
6a108a14 2659 bool "Read CNB20LE Host Bridge Windows" if EXPERT
6ea30386 2660 depends on PCI
3f6ea84a
IS
2661 help
2662 Read the PCI windows out of the CNB20LE host bridge. This allows
2663 PCI hotplug to work on systems with the CNB20LE chipset which do
2664 not have ACPI.
2665
64a5fed6
BH
2666 There's no public spec for this chipset, and this functionality
2667 is known to be incomplete.
2668
2669 You should say N unless you know you need this.
2670
3a495511 2671config ISA_BUS
17a2a129 2672 bool "ISA bus support on modern systems" if EXPERT
3a495511 2673 help
17a2a129
WBG
2674 Expose ISA bus device drivers and options available for selection and
2675 configuration. Enable this option if your target machine has an ISA
2676 bus. ISA is an older system, displaced by PCI and newer bus
2677 architectures -- if your target machine is modern, it probably does
2678 not have an ISA bus.
3a495511
WBG
2679
2680 If unsure, say N.
2681
1c00f016 2682# x86_64 have no ISA slots, but can have ISA-style DMA.
e279b6c1 2683config ISA_DMA_API
1c00f016
DR
2684 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2685 default y
2686 help
2687 Enables ISA-style DMA support for devices requiring such controllers.
2688 If unsure, say Y.
e279b6c1 2689
51e68d05
LT
2690if X86_32
2691
e279b6c1
SR
2692config ISA
2693 bool "ISA support"
a7f7f624 2694 help
e279b6c1
SR
2695 Find out whether you have ISA slots on your motherboard. ISA is the
2696 name of a bus system, i.e. the way the CPU talks to the other stuff
2697 inside your box. Other bus systems are PCI, EISA, MicroChannel
2698 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2699 newer boards don't support it. If you have ISA, say Y, otherwise N.
2700
e279b6c1
SR
2701config SCx200
2702 tristate "NatSemi SCx200 support"
a7f7f624 2703 help
e279b6c1
SR
2704 This provides basic support for National Semiconductor's
2705 (now AMD's) Geode processors. The driver probes for the
2706 PCI-IDs of several on-chip devices, so its a good dependency
2707 for other scx200_* drivers.
2708
2709 If compiled as a module, the driver is named scx200.
2710
2711config SCx200HR_TIMER
2712 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
592913ec 2713 depends on SCx200
e279b6c1 2714 default y
a7f7f624 2715 help
e279b6c1
SR
2716 This driver provides a clocksource built upon the on-chip
2717 27MHz high-resolution timer. Its also a workaround for
2718 NSC Geode SC-1100's buggy TSC, which loses time when the
2719 processor goes idle (as is done by the scheduler). The
2720 other workaround is idle=poll boot option.
2721
3ef0e1f8
AS
2722config OLPC
2723 bool "One Laptop Per Child support"
54008979 2724 depends on !X86_PAE
3c554946 2725 select GPIOLIB
dc3119e7 2726 select OF
45bb1674 2727 select OF_PROMTREE
b4e51854 2728 select IRQ_DOMAIN
0c3d931b 2729 select OLPC_EC
a7f7f624 2730 help
3ef0e1f8
AS
2731 Add support for detecting the unique features of the OLPC
2732 XO hardware.
2733
a3128588
DD
2734config OLPC_XO1_PM
2735 bool "OLPC XO-1 Power Management"
fa112cf1 2736 depends on OLPC && MFD_CS5535=y && PM_SLEEP
a7f7f624 2737 help
97c4cb71 2738 Add support for poweroff and suspend of the OLPC XO-1 laptop.
bf1ebf00 2739
cfee9597
DD
2740config OLPC_XO1_RTC
2741 bool "OLPC XO-1 Real Time Clock"
2742 depends on OLPC_XO1_PM && RTC_DRV_CMOS
a7f7f624 2743 help
cfee9597
DD
2744 Add support for the XO-1 real time clock, which can be used as a
2745 programmable wakeup source.
2746
7feda8e9
DD
2747config OLPC_XO1_SCI
2748 bool "OLPC XO-1 SCI extras"
92e830f2 2749 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
ed8e47fe 2750 depends on INPUT=y
d8d01a63 2751 select POWER_SUPPLY
a7f7f624 2752 help
7feda8e9 2753 Add support for SCI-based features of the OLPC XO-1 laptop:
7bc74b3d 2754 - EC-driven system wakeups
7feda8e9 2755 - Power button
7bc74b3d 2756 - Ebook switch
2cf2baea 2757 - Lid switch
e1040ac6
DD
2758 - AC adapter status updates
2759 - Battery status updates
7feda8e9 2760
a0f30f59
DD
2761config OLPC_XO15_SCI
2762 bool "OLPC XO-1.5 SCI extras"
d8d01a63
DD
2763 depends on OLPC && ACPI
2764 select POWER_SUPPLY
a7f7f624 2765 help
a0f30f59
DD
2766 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2767 - EC-driven system wakeups
2768 - AC adapter status updates
2769 - Battery status updates
bf1ebf00 2770
d4f3e350
EW
2771config ALIX
2772 bool "PCEngines ALIX System Support (LED setup)"
2773 select GPIOLIB
a7f7f624 2774 help
d4f3e350
EW
2775 This option enables system support for the PCEngines ALIX.
2776 At present this just sets up LEDs for GPIO control on
2777 ALIX2/3/6 boards. However, other system specific setup should
2778 get added here.
2779
2780 Note: You must still enable the drivers for GPIO and LED support
2781 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2782
2783 Note: You have to set alix.force=1 for boards with Award BIOS.
2784
da4e3302
PP
2785config NET5501
2786 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2787 select GPIOLIB
a7f7f624 2788 help
da4e3302
PP
2789 This option enables system support for the Soekris Engineering net5501.
2790
3197059a
PP
2791config GEOS
2792 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2793 select GPIOLIB
2794 depends on DMI
a7f7f624 2795 help
3197059a
PP
2796 This option enables system support for the Traverse Technologies GEOS.
2797
7d029125
VD
2798config TS5500
2799 bool "Technologic Systems TS-5500 platform support"
2800 depends on MELAN
2801 select CHECK_SIGNATURE
2802 select NEW_LEDS
2803 select LEDS_CLASS
a7f7f624 2804 help
7d029125
VD
2805 This option enables system support for the Technologic Systems TS-5500.
2806
bc0120fd
SR
2807endif # X86_32
2808
23ac4ae8 2809config AMD_NB
e279b6c1 2810 def_bool y
0e152cd7 2811 depends on CPU_SUP_AMD && PCI
e279b6c1 2812
e279b6c1
SR
2813endmenu
2814
2815
1572497c 2816menu "Binary Emulations"
e279b6c1
SR
2817
2818config IA32_EMULATION
2819 bool "IA32 Emulation"
2820 depends on X86_64
39f88911 2821 select ARCH_WANT_OLD_COMPAT_IPC
d1603990 2822 select BINFMT_ELF
39f88911 2823 select COMPAT_OLD_SIGACTION
a7f7f624 2824 help
5fd92e65
L
2825 Include code to run legacy 32-bit programs under a
2826 64-bit kernel. You should likely turn this on, unless you're
2827 100% sure that you don't have any 32-bit programs left.
e279b6c1
SR
2828
2829config IA32_AOUT
8f9ca475
IM
2830 tristate "IA32 a.out support"
2831 depends on IA32_EMULATION
eac61655 2832 depends on BROKEN
a7f7f624 2833 help
8f9ca475 2834 Support old a.out binaries in the 32bit emulation.
e279b6c1 2835
0bf62763 2836config X86_X32
6ea30386 2837 bool "x32 ABI for 64-bit mode"
9b54050b 2838 depends on X86_64
a7f7f624 2839 help
5fd92e65
L
2840 Include code to run binaries for the x32 native 32-bit ABI
2841 for 64-bit processors. An x32 process gets access to the
2842 full 64-bit register file and wide data path while leaving
2843 pointers at 32 bits for smaller memory footprint.
2844
2845 You will need a recent binutils (2.22 or later) with
2846 elf32_x86_64 support enabled to compile a kernel with this
2847 option set.
2848
953fee1d
IM
2849config COMPAT_32
2850 def_bool y
2851 depends on IA32_EMULATION || X86_32
2852 select HAVE_UID16
2853 select OLD_SIGSUSPEND3
2854
e279b6c1 2855config COMPAT
3c2362e6 2856 def_bool y
0bf62763 2857 depends on IA32_EMULATION || X86_X32
e279b6c1 2858
3120e25e 2859if COMPAT
e279b6c1 2860config COMPAT_FOR_U64_ALIGNMENT
3120e25e 2861 def_bool y
e279b6c1
SR
2862
2863config SYSVIPC_COMPAT
3c2362e6 2864 def_bool y
3120e25e 2865 depends on SYSVIPC
3120e25e 2866endif
ee009e4a 2867
e279b6c1
SR
2868endmenu
2869
2870
e5beae16
KP
2871config HAVE_ATOMIC_IOMAP
2872 def_bool y
2873 depends on X86_32
2874
edf88417 2875source "arch/x86/kvm/Kconfig"
5e8ebd84
JD
2876
2877source "arch/x86/Kconfig.assembler"