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signal, x86: Delay calling signals in atomic on RT enabled kernels
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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
bf9ad37d 123 select ARCH_WANTS_RT_DELAYED_SIGNALS
38d8b4e6 124 select ARCH_WANTS_THP_SWAP if X86_64
b5f06f64 125 select ARCH_HAS_PARANOID_L1D_FLUSH
10916706 126 select BUILDTIME_TABLE_SORT
6471b825 127 select CLKEVT_I8253
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IM
128 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
129 select CLOCKSOURCE_WATCHDOG
6471b825 130 select DCACHE_WORD_ACCESS
3aac3ebe 131 select DYNAMIC_SIGFRAME
45471cd9
LT
132 select EDAC_ATOMIC_SCRUB
133 select EDAC_SUPPORT
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IM
134 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
135 select GENERIC_CLOCKEVENTS_MIN_ADJUST
136 select GENERIC_CMOS_UPDATE
137 select GENERIC_CPU_AUTOPROBE
61dc0f55 138 select GENERIC_CPU_VULNERABILITIES
5b7c73e0 139 select GENERIC_EARLY_IOREMAP
27d6b4d1 140 select GENERIC_ENTRY
6471b825 141 select GENERIC_IOMAP
c7d6c9dd 142 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
0fa115da 143 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
ad7a929f 144 select GENERIC_IRQ_MIGRATION if SMP
6471b825 145 select GENERIC_IRQ_PROBE
c201c917 146 select GENERIC_IRQ_RESERVATION_MODE
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IM
147 select GENERIC_IRQ_SHOW
148 select GENERIC_PENDING_IRQ if SMP
2ae27137 149 select GENERIC_PTDUMP
6471b825 150 select GENERIC_SMP_IDLE_THREAD
6471b825 151 select GENERIC_TIME_VSYSCALL
7ac87074 152 select GENERIC_GETTIMEOFDAY
550a77a7 153 select GENERIC_VDSO_TIME_NS
39656e83 154 select GUP_GET_PTE_LOW_HIGH if X86_PAE
17e5888e 155 select HARDIRQS_SW_RESEND
7edaeb68 156 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
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IM
157 select HAVE_ACPI_APEI if ACPI
158 select HAVE_ACPI_APEI_NMI if ACPI
159 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
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IM
160 select HAVE_ARCH_AUDITSYSCALL
161 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
162 select HAVE_ARCH_JUMP_LABEL
b34006c4 163 select HAVE_ARCH_JUMP_LABEL_RELATIVE
d17a1d97 164 select HAVE_ARCH_KASAN if X86_64
0609ae01 165 select HAVE_ARCH_KASAN_VMALLOC if X86_64
1dc0da6e 166 select HAVE_ARCH_KFENCE
6471b825 167 select HAVE_ARCH_KGDB
9e08f57d
DC
168 select HAVE_ARCH_MMAP_RND_BITS if MMU
169 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
1b028f78 170 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
271ca788 171 select HAVE_ARCH_PREL32_RELOCATIONS
6471b825 172 select HAVE_ARCH_SECCOMP_FILTER
f7d83c1c 173 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
afaef01c 174 select HAVE_ARCH_STACKLEAK
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IM
175 select HAVE_ARCH_TRACEHOOK
176 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
a00cc7d9 177 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
b64d8d1e 178 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
7677f7fd 179 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD
e37e43a4 180 select HAVE_ARCH_VMAP_STACK if X86_64
fe950f60 181 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
c763ea26 182 select HAVE_ARCH_WITHIN_STACK_FRAMES
2ff2b7ec 183 select HAVE_ASM_MODVERSIONS
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IM
184 select HAVE_CMPXCHG_DOUBLE
185 select HAVE_CMPXCHG_LOCAL
186 select HAVE_CONTEXT_TRACKING if X86_64
d1f250e2 187 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING
cf4db259 188 select HAVE_C_RECORDMCOUNT
6dafca97 189 select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION
4ed308c4 190 select HAVE_BUILDTIME_MCOUNT_SORT
6471b825 191 select HAVE_DEBUG_KMEMLEAK
6471b825 192 select HAVE_DMA_CONTIGUOUS
677aa9f7 193 select HAVE_DYNAMIC_FTRACE
06aeaaea 194 select HAVE_DYNAMIC_FTRACE_WITH_REGS
02a474ca 195 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64
562955fe 196 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
c316eb44 197 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64
503e4510 198 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64
03f5781b 199 select HAVE_EBPF_JIT
58340a07 200 select HAVE_EFFICIENT_UNALIGNED_ACCESS
6630a8e5 201 select HAVE_EISA
5f56a5df 202 select HAVE_EXIT_THREAD
67a929e0 203 select HAVE_FAST_GUP
644e0e8d 204 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
6471b825 205 select HAVE_FTRACE_MCOUNT_RECORD
4a30e4c9 206 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE)
6471b825 207 select HAVE_FUNCTION_TRACER
6b90bd4b 208 select HAVE_GCC_PLUGINS
6471b825 209 select HAVE_HW_BREAKPOINT
6471b825 210 select HAVE_IOREMAP_PROT
624db9ea 211 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
6471b825 212 select HAVE_IRQ_TIME_ACCOUNTING
2e9f3bdd 213 select HAVE_KERNEL_BZIP2
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IM
214 select HAVE_KERNEL_GZIP
215 select HAVE_KERNEL_LZ4
2e9f3bdd 216 select HAVE_KERNEL_LZMA
13510997 217 select HAVE_KERNEL_LZO
6471b825 218 select HAVE_KERNEL_XZ
fb46d057 219 select HAVE_KERNEL_ZSTD
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IM
220 select HAVE_KPROBES
221 select HAVE_KPROBES_ON_FTRACE
540adea3 222 select HAVE_FUNCTION_ERROR_INJECTION
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IM
223 select HAVE_KRETPROBES
224 select HAVE_KVM
225 select HAVE_LIVEPATCH if X86_64
0102752e 226 select HAVE_MIXED_BREAKPOINTS_REGS
ee9f8fce 227 select HAVE_MOD_ARCH_SPECIFIC
9f132f7e 228 select HAVE_MOVE_PMD
be37c98d 229 select HAVE_MOVE_PUD
42a0bb3f 230 select HAVE_NMI
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IM
231 select HAVE_OPTPROBES
232 select HAVE_PCSPKR_PLATFORM
233 select HAVE_PERF_EVENTS
c01d4323 234 select HAVE_PERF_EVENTS_NMI
92e5aae4 235 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
eb01d42a 236 select HAVE_PCI
c5e63197 237 select HAVE_PERF_REGS
c5ebcedb 238 select HAVE_PERF_USER_STACK_DUMP
ff2e6d72 239 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
00998085 240 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
6471b825 241 select HAVE_REGS_AND_STACK_ACCESS_API
6415b38b 242 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
3c88ee19 243 select HAVE_FUNCTION_ARG_ACCESS_API
7ecd19cf 244 select HAVE_SETUP_PER_CPU_AREA
cd1a41ce 245 select HAVE_SOFTIRQ_ON_OWN_STACK
d148eac0 246 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
c763ea26 247 select HAVE_STACK_VALIDATION if X86_64
e6d6c071 248 select HAVE_STATIC_CALL
1e7e4788 249 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION
6ef869e0 250 select HAVE_PREEMPT_DYNAMIC
d6761b8f 251 select HAVE_RSEQ
6471b825 252 select HAVE_SYSCALL_TRACEPOINTS
6471b825 253 select HAVE_UNSTABLE_SCHED_CLOCK
7c68af6e 254 select HAVE_USER_RETURN_NOTIFIER
7ac87074 255 select HAVE_GENERIC_VDSO
05736e4a 256 select HOTPLUG_SMT if SMP
c0185808 257 select IRQ_FORCED_THREADING
7ecd19cf
KW
258 select NEED_PER_CPU_EMBED_FIRST_CHUNK
259 select NEED_PER_CPU_PAGE_FIRST_CHUNK
86596f0a 260 select NEED_SG_DMA_LENGTH
2eac9c2d 261 select PCI_DOMAINS if PCI
625210cf 262 select PCI_LOCKLESS_CONFIG if PCI
6471b825 263 select PERF_EVENTS
3195ef59 264 select RTC_LIB
d6faca40 265 select RTC_MC146818_LIB
6471b825 266 select SPARSE_IRQ
83fe27ea 267 select SRCU
1e7e4788 268 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
6471b825 269 select SYSCTL_EXCEPTION_TRACE
15f4eae7 270 select THREAD_INFO_IN_TASK
4aae683f 271 select TRACE_IRQFLAGS_SUPPORT
6471b825
IM
272 select USER_STACKTRACE_SUPPORT
273 select VIRT_TO_BUS
3b02a051 274 select HAVE_ARCH_KCSAN if X86_64
6471b825 275 select X86_FEATURE_NAMES if PROC_FS
0c608dad 276 select PROC_PID_ARCH_STATUS if PROC_FS
50468e43 277 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX
9e2b4be3 278 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
7d8330a5 279
ba7e4d13 280config INSTRUCTION_DECODER
3120e25e
JB
281 def_bool y
282 depends on KPROBES || PERF_EVENTS || UPROBES
ba7e4d13 283
51b26ada
LT
284config OUTPUT_FORMAT
285 string
286 default "elf32-i386" if X86_32
287 default "elf64-x86-64" if X86_64
288
8d5fffb9 289config LOCKDEP_SUPPORT
3c2362e6 290 def_bool y
8d5fffb9
SR
291
292config STACKTRACE_SUPPORT
3c2362e6 293 def_bool y
8d5fffb9 294
8d5fffb9 295config MMU
3c2362e6 296 def_bool y
8d5fffb9 297
9e08f57d
DC
298config ARCH_MMAP_RND_BITS_MIN
299 default 28 if 64BIT
300 default 8
301
302config ARCH_MMAP_RND_BITS_MAX
303 default 32 if 64BIT
304 default 16
305
306config ARCH_MMAP_RND_COMPAT_BITS_MIN
307 default 8
308
309config ARCH_MMAP_RND_COMPAT_BITS_MAX
310 default 16
311
8d5fffb9
SR
312config SBUS
313 bool
314
315config GENERIC_ISA_DMA
3120e25e
JB
316 def_bool y
317 depends on ISA_DMA_API
8d5fffb9 318
8d5fffb9 319config GENERIC_BUG
3c2362e6 320 def_bool y
8d5fffb9 321 depends on BUG
b93a531e
JB
322 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
323
324config GENERIC_BUG_RELATIVE_POINTERS
325 bool
8d5fffb9 326
8d5fffb9 327config ARCH_MAY_HAVE_PC_FDC
3120e25e
JB
328 def_bool y
329 depends on ISA_DMA_API
8d5fffb9 330
1032c0ba
SR
331config GENERIC_CALIBRATE_DELAY
332 def_bool y
333
9a0b8415 334config ARCH_HAS_CPU_RELAX
335 def_bool y
336
316d097c
DH
337config ARCH_HAS_FILTER_PGPROT
338 def_bool y
339
801e4062
JB
340config ARCH_HIBERNATION_POSSIBLE
341 def_bool y
801e4062 342
d7109fe3
AS
343config ARCH_NR_GPIO
344 int
345 default 1024 if X86_64
346 default 512
347
f4cb5700
JB
348config ARCH_SUSPEND_POSSIBLE
349 def_bool y
f4cb5700 350
53313b2c
SC
351config ARCH_WANT_GENERAL_HUGETLB
352 def_bool y
353
8d5fffb9 354config AUDIT_ARCH
e0fd24a3 355 def_bool y if X86_64
8d5fffb9 356
d6f2d75a
AR
357config KASAN_SHADOW_OFFSET
358 hex
359 depends on KASAN
360 default 0xdffffc0000000000
361
69575d38
SW
362config HAVE_INTEL_TXT
363 def_bool y
6ea30386 364 depends on INTEL_IOMMU && ACPI
69575d38 365
6b0c3d44
SR
366config X86_32_SMP
367 def_bool y
368 depends on X86_32 && SMP
369
370config X86_64_SMP
371 def_bool y
372 depends on X86_64 && SMP
373
2b144498
SD
374config ARCH_SUPPORTS_UPROBES
375 def_bool y
376
d20642f0
RH
377config FIX_EARLYCON_MEM
378 def_bool y
379
94d49eb3
KS
380config DYNAMIC_PHYSICAL_MASK
381 bool
382
98233368
KS
383config PGTABLE_LEVELS
384 int
77ef56e4 385 default 5 if X86_5LEVEL
98233368
KS
386 default 4 if X86_64
387 default 3 if X86_PAE
388 default 2
389
2a61f474
MY
390config CC_HAS_SANE_STACKPROTECTOR
391 bool
392 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
393 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
394 help
395 We have to make sure stack protector is unconditionally disabled if
3fb0fdb3
AL
396 the compiler produces broken code or if it does not let us control
397 the segment on 32-bit kernels.
2a61f474 398
506f1d07
SR
399menu "Processor type and features"
400
506f1d07
SR
401config SMP
402 bool "Symmetric multi-processing support"
a7f7f624 403 help
506f1d07 404 This enables support for systems with more than one CPU. If you have
4a474157
RG
405 a system with only one CPU, say N. If you have a system with more
406 than one CPU, say Y.
506f1d07 407
4a474157 408 If you say N here, the kernel will run on uni- and multiprocessor
506f1d07
SR
409 machines, but will use only one CPU of a multiprocessor machine. If
410 you say Y here, the kernel will run on many, but not all,
4a474157 411 uniprocessor machines. On a uniprocessor machine, the kernel
506f1d07
SR
412 will run faster if you say N here.
413
414 Note that if you say Y here and choose architecture "586" or
415 "Pentium" under "Processor family", the kernel will not work on 486
416 architectures. Similarly, multiprocessor kernels for the "PPro"
417 architecture may not work on all Pentium based boards.
418
419 People using multiprocessor machines who say Y here should also say
420 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
421 Management" code will be disabled if you say Y here.
422
cb1aaebe 423 See also <file:Documentation/x86/i386/IO-APIC.rst>,
4f4cfa6c 424 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
506f1d07
SR
425 <http://www.tldp.org/docs.html#howto>.
426
427 If you don't know what to do here, say N.
428
9def39be
JT
429config X86_FEATURE_NAMES
430 bool "Processor feature human-readable names" if EMBEDDED
431 default y
a7f7f624 432 help
9def39be
JT
433 This option compiles in a table of x86 feature bits and corresponding
434 names. This is required to support /proc/cpuinfo and a few kernel
435 messages. You can disable this to save space, at the expense of
436 making those few kernel messages show numeric feature bits instead.
437
438 If in doubt, say Y.
439
06cd9a7d
YL
440config X86_X2APIC
441 bool "Support x2apic"
19e3d60d 442 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
a7f7f624 443 help
06cd9a7d
YL
444 This enables x2apic support on CPUs that have this feature.
445
446 This allows 32-bit apic IDs (so it can support very large systems),
447 and accesses the local apic via MSRs not via mmio.
448
06cd9a7d
YL
449 If you don't know what to do here, say N.
450
6695c85b 451config X86_MPPARSE
4590d98f 452 bool "Enable MPS table" if ACPI
7a527688 453 default y
5ab74722 454 depends on X86_LOCAL_APIC
a7f7f624 455 help
6695c85b
YL
456 For old smp systems that do not have proper acpi support. Newer systems
457 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
6695c85b 458
ddd70cf9 459config GOLDFISH
b03b016f
KK
460 def_bool y
461 depends on X86_GOLDFISH
ddd70cf9 462
76b04384
DW
463config RETPOLINE
464 bool "Avoid speculative indirect branches in kernel"
465 default y
466 help
467 Compile kernel with the retpoline compiler options to guard against
468 kernel-to-user data leaks by avoiding speculative indirect
469 branches. Requires a compiler with -mindirect-branch=thunk-extern
470 support for full protection. The kernel may run slower.
471
e463a09a
PZ
472config CC_HAS_SLS
473 def_bool $(cc-option,-mharden-sls=all)
474
475config SLS
476 bool "Mitigate Straight-Line-Speculation"
477 depends on CC_HAS_SLS && X86_64
478 default n
479 help
480 Compile the kernel with straight-line-speculation options to guard
481 against straight line speculation. The kernel image might be slightly
482 larger.
483
e6d42931
JW
484config X86_CPU_RESCTRL
485 bool "x86 CPU resource control support"
6fe07ce3 486 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
59fe5a77 487 select KERNFS
e79f15a4 488 select PROC_CPU_RESCTRL if PROC_FS
78e99b4a 489 help
e6d42931 490 Enable x86 CPU resource control support.
6fe07ce3
BM
491
492 Provide support for the allocation and monitoring of system resources
493 usage by the CPU.
494
495 Intel calls this Intel Resource Director Technology
496 (Intel(R) RDT). More information about RDT can be found in the
497 Intel x86 Architecture Software Developer Manual.
498
499 AMD calls this AMD Platform Quality of Service (AMD QoS).
500 More information about AMD QoS can be found in the AMD64 Technology
501 Platform Quality of Service Extensions manual.
78e99b4a
FY
502
503 Say N if unsure.
504
8425091f 505if X86_32
a0d0bb4d
RD
506config X86_BIGSMP
507 bool "Support for big SMP systems with more than 8 CPUs"
508 depends on SMP
a7f7f624 509 help
e133f6ea 510 This option is needed for the systems that have more than 8 CPUs.
a0d0bb4d 511
c5c606d9
RT
512config X86_EXTENDED_PLATFORM
513 bool "Support for extended (non-PC) x86 platforms"
514 default y
a7f7f624 515 help
06ac8346
IM
516 If you disable this option then the kernel will only support
517 standard PC platforms. (which covers the vast majority of
518 systems out there.)
519
8425091f
RT
520 If you enable this option then you'll be able to select support
521 for the following (non-PC) 32 bit x86 platforms:
cb7b8023 522 Goldfish (Android emulator)
8425091f 523 AMD Elan
8425091f
RT
524 RDC R-321x SoC
525 SGI 320/540 (Visual Workstation)
83125a3a 526 STA2X11-based (e.g. Northville)
3f4110a4 527 Moorestown MID devices
06ac8346
IM
528
529 If you have one of these systems, or if you want to build a
530 generic distribution kernel, say Y here - otherwise say N.
8425091f 531endif
06ac8346 532
8425091f
RT
533if X86_64
534config X86_EXTENDED_PLATFORM
535 bool "Support for extended (non-PC) x86 platforms"
536 default y
a7f7f624 537 help
8425091f
RT
538 If you disable this option then the kernel will only support
539 standard PC platforms. (which covers the vast majority of
540 systems out there.)
541
542 If you enable this option then you'll be able to select support
543 for the following (non-PC) 64 bit x86 platforms:
44b111b5 544 Numascale NumaChip
8425091f
RT
545 ScaleMP vSMP
546 SGI Ultraviolet
547
548 If you have one of these systems, or if you want to build a
549 generic distribution kernel, say Y here - otherwise say N.
550endif
c5c606d9
RT
551# This is an alphabetically sorted list of 64 bit extended platforms
552# Please maintain the alphabetic order if and when there are additions
44b111b5
SP
553config X86_NUMACHIP
554 bool "Numascale NumaChip"
555 depends on X86_64
556 depends on X86_EXTENDED_PLATFORM
557 depends on NUMA
558 depends on SMP
559 depends on X86_X2APIC
f9726bfd 560 depends on PCI_MMCONFIG
a7f7f624 561 help
44b111b5
SP
562 Adds support for Numascale NumaChip large-SMP systems. Needed to
563 enable more than ~168 cores.
564 If you don't have one of these, you should say N here.
506f1d07 565
c5c606d9
RT
566config X86_VSMP
567 bool "ScaleMP vSMP"
6276a074 568 select HYPERVISOR_GUEST
c5c606d9
RT
569 select PARAVIRT
570 depends on X86_64 && PCI
571 depends on X86_EXTENDED_PLATFORM
ead91d4b 572 depends on SMP
a7f7f624 573 help
c5c606d9
RT
574 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
575 supposed to run on these EM64T-based machines. Only choose this option
576 if you have one of these machines.
5e3a77e9 577
03b48632
NP
578config X86_UV
579 bool "SGI Ultraviolet"
580 depends on X86_64
c5c606d9 581 depends on X86_EXTENDED_PLATFORM
54c28d29 582 depends on NUMA
1ecb4ae5 583 depends on EFI
c2209ea5 584 depends on KEXEC_CORE
9d6c26e7 585 depends on X86_X2APIC
1222e564 586 depends on PCI
a7f7f624 587 help
03b48632
NP
588 This option is needed in order to support SGI Ultraviolet systems.
589 If you don't have one of these, you should say N here.
590
c5c606d9
RT
591# Following is an alphabetically sorted list of 32 bit extended platforms
592# Please maintain the alphabetic order if and when there are additions
506f1d07 593
ddd70cf9 594config X86_GOLDFISH
b03b016f
KK
595 bool "Goldfish (Virtual Platform)"
596 depends on X86_EXTENDED_PLATFORM
a7f7f624 597 help
ddd70cf9
JN
598 Enable support for the Goldfish virtual platform used primarily
599 for Android development. Unless you are building for the Android
600 Goldfish emulator say N here.
601
c751e17b
TG
602config X86_INTEL_CE
603 bool "CE4100 TV platform"
604 depends on PCI
605 depends on PCI_GODIRECT
6084a6e2 606 depends on X86_IO_APIC
c751e17b
TG
607 depends on X86_32
608 depends on X86_EXTENDED_PLATFORM
37bc9f50 609 select X86_REBOOTFIXUPS
da6b737b
SAS
610 select OF
611 select OF_EARLY_FLATTREE
a7f7f624 612 help
c751e17b
TG
613 Select for the Intel CE media processor (CE4100) SOC.
614 This option compiles in support for the CE4100 SOC for settop
615 boxes and media devices.
616
4cb9b00f 617config X86_INTEL_MID
43605ef1 618 bool "Intel MID platform support"
43605ef1 619 depends on X86_EXTENDED_PLATFORM
edc6bc78 620 depends on X86_PLATFORM_DEVICES
1ea7c673 621 depends on PCI
3fda5bb4 622 depends on X86_64 || (PCI_GOANY && X86_32)
1ea7c673 623 depends on X86_IO_APIC
4cb9b00f 624 select I2C
7c9c3a1e 625 select DW_APB_TIMER
54b34aa0 626 select INTEL_SCU_PCI
a7f7f624 627 help
4cb9b00f
DC
628 Select to build a kernel capable of supporting Intel MID (Mobile
629 Internet Device) platform systems which do not have the PCI legacy
630 interfaces. If you are building for a PC class system say N here.
1ea7c673 631
4cb9b00f
DC
632 Intel MID platforms are based on an Intel processor and chipset which
633 consume less power than most of the x86 derivatives.
43605ef1 634
8bbc2a13
BD
635config X86_INTEL_QUARK
636 bool "Intel Quark platform support"
637 depends on X86_32
638 depends on X86_EXTENDED_PLATFORM
639 depends on X86_PLATFORM_DEVICES
640 depends on X86_TSC
641 depends on PCI
642 depends on PCI_GOANY
643 depends on X86_IO_APIC
644 select IOSF_MBI
645 select INTEL_IMR
9ab6eb51 646 select COMMON_CLK
a7f7f624 647 help
8bbc2a13
BD
648 Select to include support for Quark X1000 SoC.
649 Say Y here if you have a Quark based system such as the Arduino
650 compatible Intel Galileo.
651
3d48aab1
MW
652config X86_INTEL_LPSS
653 bool "Intel Low Power Subsystem Support"
5962dd22 654 depends on X86 && ACPI && PCI
3d48aab1 655 select COMMON_CLK
0f531431 656 select PINCTRL
eebb3e8d 657 select IOSF_MBI
a7f7f624 658 help
3d48aab1
MW
659 Select to build support for Intel Low Power Subsystem such as
660 found on Intel Lynxpoint PCH. Selecting this option enables
0f531431
MN
661 things like clock tree (common clock framework) and pincontrol
662 which are needed by the LPSS peripheral drivers.
3d48aab1 663
92082a88
KX
664config X86_AMD_PLATFORM_DEVICE
665 bool "AMD ACPI2Platform devices support"
666 depends on ACPI
667 select COMMON_CLK
668 select PINCTRL
a7f7f624 669 help
92082a88
KX
670 Select to interpret AMD specific ACPI device to platform device
671 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
672 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
673 implemented under PINCTRL subsystem.
674
ced3ce76
DB
675config IOSF_MBI
676 tristate "Intel SoC IOSF Sideband support for SoC platforms"
677 depends on PCI
a7f7f624 678 help
ced3ce76
DB
679 This option enables sideband register access support for Intel SoC
680 platforms. On these platforms the IOSF sideband is used in lieu of
681 MSR's for some register accesses, mostly but not limited to thermal
682 and power. Drivers may query the availability of this device to
683 determine if they need the sideband in order to work on these
684 platforms. The sideband is available on the following SoC products.
685 This list is not meant to be exclusive.
686 - BayTrail
687 - Braswell
688 - Quark
689
690 You should say Y if you are running a kernel on one of these SoC's.
691
ed2226bd
DB
692config IOSF_MBI_DEBUG
693 bool "Enable IOSF sideband access through debugfs"
694 depends on IOSF_MBI && DEBUG_FS
a7f7f624 695 help
ed2226bd
DB
696 Select this option to expose the IOSF sideband access registers (MCR,
697 MDR, MCRX) through debugfs to write and read register information from
698 different units on the SoC. This is most useful for obtaining device
699 state information for debug and analysis. As this is a general access
700 mechanism, users of this option would have specific knowledge of the
701 device they want to access.
702
703 If you don't require the option or are in doubt, say N.
704
c5c606d9
RT
705config X86_RDC321X
706 bool "RDC R-321x SoC"
506f1d07 707 depends on X86_32
c5c606d9
RT
708 depends on X86_EXTENDED_PLATFORM
709 select M486
710 select X86_REBOOTFIXUPS
a7f7f624 711 help
c5c606d9
RT
712 This option is needed for RDC R-321x system-on-chip, also known
713 as R-8610-(G).
714 If you don't have one of these chips, you should say N here.
715
e0c7ae37 716config X86_32_NON_STANDARD
9c398017
IM
717 bool "Support non-standard 32-bit SMP architectures"
718 depends on X86_32 && SMP
c5c606d9 719 depends on X86_EXTENDED_PLATFORM
a7f7f624 720 help
b5660ba7
PA
721 This option compiles in the bigsmp and STA2X11 default
722 subarchitectures. It is intended for a generic binary
723 kernel. If you select them all, kernel will probe it one by
724 one and will fallback to default.
d49c4288 725
c5c606d9 726# Alphabetically sorted list of Non standard 32 bit platforms
d49c4288 727
d949f36f 728config X86_SUPPORTS_MEMORY_FAILURE
6fc108a0 729 def_bool y
d949f36f
LT
730 # MCE code calls memory_failure():
731 depends on X86_MCE
732 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
d949f36f
LT
733 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
734 depends on X86_64 || !SPARSEMEM
735 select ARCH_SUPPORTS_MEMORY_FAILURE
d949f36f 736
83125a3a
AR
737config STA2X11
738 bool "STA2X11 Companion Chip Support"
739 depends on X86_32_NON_STANDARD && PCI
83125a3a
AR
740 select SWIOTLB
741 select MFD_STA2X11
0145071b 742 select GPIOLIB
a7f7f624 743 help
83125a3a
AR
744 This adds support for boards based on the STA2X11 IO-Hub,
745 a.k.a. "ConneXt". The chip is used in place of the standard
746 PC chipset, so all "standard" peripherals are missing. If this
747 option is selected the kernel will still be able to boot on
748 standard PC machines.
749
82148d1d
S
750config X86_32_IRIS
751 tristate "Eurobraille/Iris poweroff module"
752 depends on X86_32
a7f7f624 753 help
82148d1d
S
754 The Iris machines from EuroBraille do not have APM or ACPI support
755 to shut themselves down properly. A special I/O sequence is
756 needed to do so, which is what this module does at
757 kernel shutdown.
758
759 This is only for Iris machines from EuroBraille.
760
761 If unused, say N.
762
ae1e9130 763config SCHED_OMIT_FRAME_POINTER
3c2362e6
HH
764 def_bool y
765 prompt "Single-depth WCHAN output"
a87d0914 766 depends on X86
a7f7f624 767 help
506f1d07
SR
768 Calculate simpler /proc/<PID>/wchan values. If this option
769 is disabled then wchan values will recurse back to the
770 caller function. This provides more accurate wchan values,
771 at the expense of slightly more scheduling overhead.
772
773 If in doubt, say "Y".
774
6276a074
BP
775menuconfig HYPERVISOR_GUEST
776 bool "Linux guest support"
a7f7f624 777 help
6276a074
BP
778 Say Y here to enable options for running Linux under various hyper-
779 visors. This option enables basic hypervisor detection and platform
780 setup.
506f1d07 781
6276a074
BP
782 If you say N, all options in this submenu will be skipped and
783 disabled, and Linux guest support won't be built in.
506f1d07 784
6276a074 785if HYPERVISOR_GUEST
506f1d07 786
e61bd94a
EPH
787config PARAVIRT
788 bool "Enable paravirtualization code"
a0e2bf7c 789 depends on HAVE_STATIC_CALL
a7f7f624 790 help
e61bd94a
EPH
791 This changes the kernel so it can modify itself when it is run
792 under a hypervisor, potentially improving performance significantly
793 over full virtualization. However, when run without a hypervisor
794 the kernel is theoretically slower and slightly larger.
795
c00a280a
JG
796config PARAVIRT_XXL
797 bool
798
6276a074
BP
799config PARAVIRT_DEBUG
800 bool "paravirt-ops debugging"
801 depends on PARAVIRT && DEBUG_KERNEL
a7f7f624 802 help
6276a074
BP
803 Enable to debug paravirt_ops internals. Specifically, BUG if
804 a paravirt_op is missing when it is called.
805
b4ecc126
JF
806config PARAVIRT_SPINLOCKS
807 bool "Paravirtualization layer for spinlocks"
6ea30386 808 depends on PARAVIRT && SMP
a7f7f624 809 help
b4ecc126
JF
810 Paravirtualized spinlocks allow a pvops backend to replace the
811 spinlock implementation with something virtualization-friendly
812 (for example, block the virtual CPU rather than spinning).
813
4c4e4f61
R
814 It has a minimal impact on native kernels and gives a nice performance
815 benefit on paravirtualized KVM / Xen kernels.
b4ecc126 816
4c4e4f61 817 If you are unsure how to answer this question, answer Y.
b4ecc126 818
ecca2502
ZY
819config X86_HV_CALLBACK_VECTOR
820 def_bool n
821
6276a074 822source "arch/x86/xen/Kconfig"
7af192c9 823
6276a074
BP
824config KVM_GUEST
825 bool "KVM Guest support (including kvmclock)"
826 depends on PARAVIRT
827 select PARAVIRT_CLOCK
a1c4423b 828 select ARCH_CPUIDLE_HALTPOLL
b1d40575 829 select X86_HV_CALLBACK_VECTOR
6276a074 830 default y
a7f7f624 831 help
6276a074
BP
832 This option enables various optimizations for running under the KVM
833 hypervisor. It includes a paravirtualized clock, so that instead
834 of relying on a PIT (or probably other) emulation by the
835 underlying device model, the host provides the guest with
836 timing infrastructure such as time of day, and system time
506f1d07 837
a1c4423b 838config ARCH_CPUIDLE_HALTPOLL
b03b016f
KK
839 def_bool n
840 prompt "Disable host haltpoll when loading haltpoll driver"
841 help
a1c4423b
MT
842 If virtualized under KVM, disable host haltpoll.
843
7733607f
MW
844config PVH
845 bool "Support for running PVH guests"
a7f7f624 846 help
7733607f
MW
847 This option enables the PVH entry point for guest virtual machines
848 as specified in the x86/HVM direct boot ABI.
849
6276a074
BP
850config PARAVIRT_TIME_ACCOUNTING
851 bool "Paravirtual steal time accounting"
852 depends on PARAVIRT
a7f7f624 853 help
6276a074
BP
854 Select this option to enable fine granularity task steal time
855 accounting. Time spent executing other tasks in parallel with
856 the current vCPU is discounted from the vCPU power. To account for
857 that, there can be a small performance impact.
858
859 If in doubt, say N here.
860
861config PARAVIRT_CLOCK
862 bool
97349135 863
4a362601
JK
864config JAILHOUSE_GUEST
865 bool "Jailhouse non-root cell support"
abde587b 866 depends on X86_64 && PCI
87e65d05 867 select X86_PM_TIMER
a7f7f624 868 help
4a362601
JK
869 This option allows to run Linux as guest in a Jailhouse non-root
870 cell. You can leave this option disabled if you only want to start
871 Jailhouse and run Linux afterwards in the root cell.
872
ec7972c9
ZY
873config ACRN_GUEST
874 bool "ACRN Guest support"
875 depends on X86_64
498ad393 876 select X86_HV_CALLBACK_VECTOR
ec7972c9
ZY
877 help
878 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
879 a flexible, lightweight reference open-source hypervisor, built with
880 real-time and safety-criticality in mind. It is built for embedded
881 IOT with small footprint and real-time features. More details can be
882 found in https://projectacrn.org/.
883
6276a074 884endif #HYPERVISOR_GUEST
97349135 885
506f1d07
SR
886source "arch/x86/Kconfig.cpu"
887
888config HPET_TIMER
3c2362e6 889 def_bool X86_64
506f1d07 890 prompt "HPET Timer Support" if X86_32
a7f7f624 891 help
8f9ca475
IM
892 Use the IA-PC HPET (High Precision Event Timer) to manage
893 time in preference to the PIT and RTC, if a HPET is
894 present.
895 HPET is the next generation timer replacing legacy 8254s.
896 The HPET provides a stable time base on SMP
897 systems, unlike the TSC, but it is more expensive to access,
4e7f9df2
MT
898 as it is off-chip. The interface used is documented
899 in the HPET spec, revision 1.
506f1d07 900
8f9ca475
IM
901 You can safely choose Y here. However, HPET will only be
902 activated if the platform and the BIOS support this feature.
903 Otherwise the 8254 will be used for timing services.
506f1d07 904
8f9ca475 905 Choose N to continue using the legacy 8254 timer.
506f1d07
SR
906
907config HPET_EMULATE_RTC
3c2362e6 908 def_bool y
3228e1dc 909 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
506f1d07 910
6a108a14 911# Mark as expert because too many people got it wrong.
506f1d07 912# The code disables itself when not needed.
7ae9392c
TP
913config DMI
914 default y
cf074402 915 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
6a108a14 916 bool "Enable DMI scanning" if EXPERT
a7f7f624 917 help
7ae9392c
TP
918 Enabled scanning of DMI to identify machine quirks. Say Y
919 here unless you have verified that your setup is not
920 affected by entries in the DMI blacklist. Required by PNP
921 BIOS code.
922
506f1d07 923config GART_IOMMU
38901f1c 924 bool "Old AMD GART IOMMU support"
2f9237d4 925 select DMA_OPS
a4ce5a48 926 select IOMMU_HELPER
506f1d07 927 select SWIOTLB
23ac4ae8 928 depends on X86_64 && PCI && AMD_NB
a7f7f624 929 help
ced3c42c
IM
930 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
931 GART based hardware IOMMUs.
932
933 The GART supports full DMA access for devices with 32-bit access
934 limitations, on systems with more than 3 GB. This is usually needed
935 for USB, sound, many IDE/SATA chipsets and some other devices.
936
937 Newer systems typically have a modern AMD IOMMU, supported via
938 the CONFIG_AMD_IOMMU=y config option.
939
940 In normal configurations this driver is only active when needed:
941 there's more than 3 GB of memory and the system contains a
942 32-bit limited device.
943
944 If unsure, say Y.
506f1d07 945
1184dc2f 946config MAXSMP
ddb0c5a6 947 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
6ea30386 948 depends on X86_64 && SMP && DEBUG_KERNEL
36f5101a 949 select CPUMASK_OFFSTACK
a7f7f624 950 help
ddb0c5a6 951 Enable maximum number of CPUS and NUMA Nodes for this architecture.
1184dc2f 952 If unsure, say N.
506f1d07 953
aec6487e
IM
954#
955# The maximum number of CPUs supported:
956#
957# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
958# and which can be configured interactively in the
959# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
960#
961# The ranges are different on 32-bit and 64-bit kernels, depending on
962# hardware capabilities and scalability features of the kernel.
963#
964# ( If MAXSMP is enabled we just use the highest possible value and disable
965# interactive configuration. )
966#
967
968config NR_CPUS_RANGE_BEGIN
a0d0bb4d 969 int
aec6487e
IM
970 default NR_CPUS_RANGE_END if MAXSMP
971 default 1 if !SMP
972 default 2
a0d0bb4d 973
aec6487e 974config NR_CPUS_RANGE_END
a0d0bb4d 975 int
aec6487e
IM
976 depends on X86_32
977 default 64 if SMP && X86_BIGSMP
978 default 8 if SMP && !X86_BIGSMP
979 default 1 if !SMP
a0d0bb4d 980
aec6487e 981config NR_CPUS_RANGE_END
a0d0bb4d 982 int
aec6487e 983 depends on X86_64
1edae1ae
SW
984 default 8192 if SMP && CPUMASK_OFFSTACK
985 default 512 if SMP && !CPUMASK_OFFSTACK
aec6487e 986 default 1 if !SMP
a0d0bb4d 987
aec6487e 988config NR_CPUS_DEFAULT
a0d0bb4d
RD
989 int
990 depends on X86_32
aec6487e
IM
991 default 32 if X86_BIGSMP
992 default 8 if SMP
993 default 1 if !SMP
a0d0bb4d 994
aec6487e 995config NR_CPUS_DEFAULT
a0d0bb4d
RD
996 int
997 depends on X86_64
aec6487e
IM
998 default 8192 if MAXSMP
999 default 64 if SMP
1000 default 1 if !SMP
a0d0bb4d 1001
506f1d07 1002config NR_CPUS
36f5101a 1003 int "Maximum number of CPUs" if SMP && !MAXSMP
aec6487e
IM
1004 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1005 default NR_CPUS_DEFAULT
a7f7f624 1006 help
506f1d07 1007 This allows you to specify the maximum number of CPUs which this
bb61ccc7 1008 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
cad14bb9 1009 supported value is 8192, otherwise the maximum value is 512. The
506f1d07
SR
1010 minimum value which makes sense is 2.
1011
aec6487e
IM
1012 This is purely to save memory: each supported CPU adds about 8KB
1013 to the kernel image.
506f1d07 1014
66558b73
TC
1015config SCHED_CLUSTER
1016 bool "Cluster scheduler support"
1017 depends on SMP
1018 default y
1019 help
1020 Cluster scheduler support improves the CPU scheduler's decision
1021 making when dealing with machines that have clusters of CPUs.
1022 Cluster usually means a couple of CPUs which are placed closely
1023 by sharing mid-level caches, last-level cache tags or internal
1024 busses.
1025
506f1d07 1026config SCHED_SMT
dbe73364 1027 def_bool y if SMP
506f1d07
SR
1028
1029config SCHED_MC
3c2362e6
HH
1030 def_bool y
1031 prompt "Multi-core scheduler support"
c8e56d20 1032 depends on SMP
a7f7f624 1033 help
506f1d07
SR
1034 Multi-core scheduler support improves the CPU scheduler's decision
1035 making when dealing with multi-core CPU chips at a cost of slightly
1036 increased overhead in some places. If unsure say N here.
1037
de966cf4
TC
1038config SCHED_MC_PRIO
1039 bool "CPU core priorities scheduler support"
0a21fc12
IM
1040 depends on SCHED_MC && CPU_SUP_INTEL
1041 select X86_INTEL_PSTATE
1042 select CPU_FREQ
de966cf4 1043 default y
a7f7f624 1044 help
0a21fc12
IM
1045 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1046 core ordering determined at manufacturing time, which allows
1047 certain cores to reach higher turbo frequencies (when running
1048 single threaded workloads) than others.
de966cf4 1049
0a21fc12
IM
1050 Enabling this kernel feature teaches the scheduler about
1051 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1052 scheduler's CPU selection logic accordingly, so that higher
1053 overall system performance can be achieved.
de966cf4 1054
0a21fc12 1055 This feature will have no effect on CPUs without this feature.
de966cf4 1056
0a21fc12 1057 If unsure say Y here.
5e76b2ab 1058
30b8b006 1059config UP_LATE_INIT
b03b016f
KK
1060 def_bool y
1061 depends on !SMP && X86_LOCAL_APIC
30b8b006 1062
506f1d07 1063config X86_UP_APIC
50849eef
JB
1064 bool "Local APIC support on uniprocessors" if !PCI_MSI
1065 default PCI_MSI
38a1dfda 1066 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
a7f7f624 1067 help
506f1d07
SR
1068 A local APIC (Advanced Programmable Interrupt Controller) is an
1069 integrated interrupt controller in the CPU. If you have a single-CPU
1070 system which has a processor with a local APIC, you can say Y here to
1071 enable and use it. If you say Y here even though your machine doesn't
1072 have a local APIC, then the kernel will still run with no slowdown at
1073 all. The local APIC supports CPU-generated self-interrupts (timer,
1074 performance counters), and the NMI watchdog which detects hard
1075 lockups.
1076
1077config X86_UP_IOAPIC
1078 bool "IO-APIC support on uniprocessors"
1079 depends on X86_UP_APIC
a7f7f624 1080 help
506f1d07
SR
1081 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1082 SMP-capable replacement for PC-style interrupt controllers. Most
1083 SMP systems and many recent uniprocessor systems have one.
1084
1085 If you have a single-CPU system with an IO-APIC, you can say Y here
1086 to use it. If you say Y here even though your machine doesn't have
1087 an IO-APIC, then the kernel will still run with no slowdown at all.
1088
1089config X86_LOCAL_APIC
3c2362e6 1090 def_bool y
0dbc6078 1091 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
b5dc8e6c 1092 select IRQ_DOMAIN_HIERARCHY
52f518a3 1093 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
506f1d07
SR
1094
1095config X86_IO_APIC
b1da1e71
JB
1096 def_bool y
1097 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
506f1d07 1098
41b9eb26
SA
1099config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1100 bool "Reroute for broken boot IRQs"
41b9eb26 1101 depends on X86_IO_APIC
a7f7f624 1102 help
41b9eb26
SA
1103 This option enables a workaround that fixes a source of
1104 spurious interrupts. This is recommended when threaded
1105 interrupt handling is used on systems where the generation of
1106 superfluous "boot interrupts" cannot be disabled.
1107
1108 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1109 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1110 kernel does during interrupt handling). On chipsets where this
1111 boot IRQ generation cannot be disabled, this workaround keeps
1112 the original IRQ line masked so that only the equivalent "boot
1113 IRQ" is delivered to the CPUs. The workaround also tells the
1114 kernel to set up the IRQ handler on the boot IRQ line. In this
1115 way only one interrupt is delivered to the kernel. Otherwise
1116 the spurious second interrupt may cause the kernel to bring
1117 down (vital) interrupt lines.
1118
1119 Only affects "broken" chipsets. Interrupt sharing may be
1120 increased on these systems.
1121
506f1d07 1122config X86_MCE
bab9bc65 1123 bool "Machine Check / overheating reporting"
648ed940 1124 select GENERIC_ALLOCATOR
e57dbaf7 1125 default y
a7f7f624 1126 help
bab9bc65
AK
1127 Machine Check support allows the processor to notify the
1128 kernel if it detects a problem (e.g. overheating, data corruption).
506f1d07 1129 The action the kernel takes depends on the severity of the problem,
bab9bc65 1130 ranging from warning messages to halting the machine.
4efc0670 1131
5de97c9f
TL
1132config X86_MCELOG_LEGACY
1133 bool "Support for deprecated /dev/mcelog character device"
1134 depends on X86_MCE
a7f7f624 1135 help
5de97c9f
TL
1136 Enable support for /dev/mcelog which is needed by the old mcelog
1137 userspace logging daemon. Consider switching to the new generation
1138 rasdaemon solution.
1139
506f1d07 1140config X86_MCE_INTEL
3c2362e6
HH
1141 def_bool y
1142 prompt "Intel MCE features"
c1ebf835 1143 depends on X86_MCE && X86_LOCAL_APIC
a7f7f624 1144 help
506f1d07
SR
1145 Additional support for intel specific MCE features such as
1146 the thermal monitor.
1147
1148config X86_MCE_AMD
3c2362e6
HH
1149 def_bool y
1150 prompt "AMD MCE features"
f5382de9 1151 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
a7f7f624 1152 help
506f1d07
SR
1153 Additional support for AMD specific MCE features such as
1154 the DRAM Error Threshold.
1155
4efc0670 1156config X86_ANCIENT_MCE
6fc108a0 1157 bool "Support for old Pentium 5 / WinChip machine checks"
c31d9633 1158 depends on X86_32 && X86_MCE
a7f7f624 1159 help
cd13adcc 1160 Include support for machine check handling on old Pentium 5 or WinChip
5065a706 1161 systems. These typically need to be enabled explicitly on the command
cd13adcc 1162 line.
4efc0670 1163
b2762686
AK
1164config X86_MCE_THRESHOLD
1165 depends on X86_MCE_AMD || X86_MCE_INTEL
6fc108a0 1166 def_bool y
b2762686 1167
ea149b36 1168config X86_MCE_INJECT
bc8e80d5 1169 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
ea149b36 1170 tristate "Machine check injector support"
a7f7f624 1171 help
ea149b36
AK
1172 Provide support for injecting machine checks for testing purposes.
1173 If you don't know what a machine check is and you don't do kernel
1174 QA it is safe to say n.
1175
07dc900e 1176source "arch/x86/events/Kconfig"
e633c65a 1177
5aef51c3 1178config X86_LEGACY_VM86
1e642812 1179 bool "Legacy VM86 support"
506f1d07 1180 depends on X86_32
a7f7f624 1181 help
5aef51c3
AL
1182 This option allows user programs to put the CPU into V8086
1183 mode, which is an 80286-era approximation of 16-bit real mode.
1184
1185 Some very old versions of X and/or vbetool require this option
1186 for user mode setting. Similarly, DOSEMU will use it if
1187 available to accelerate real mode DOS programs. However, any
1188 recent version of DOSEMU, X, or vbetool should be fully
1189 functional even without kernel VM86 support, as they will all
1e642812
IM
1190 fall back to software emulation. Nevertheless, if you are using
1191 a 16-bit DOS program where 16-bit performance matters, vm86
1192 mode might be faster than emulation and you might want to
1193 enable this option.
5aef51c3 1194
1e642812
IM
1195 Note that any app that works on a 64-bit kernel is unlikely to
1196 need this option, as 64-bit kernels don't, and can't, support
1197 V8086 mode. This option is also unrelated to 16-bit protected
1198 mode and is not needed to run most 16-bit programs under Wine.
5aef51c3 1199
1e642812
IM
1200 Enabling this option increases the complexity of the kernel
1201 and slows down exception handling a tiny bit.
5aef51c3 1202
1e642812 1203 If unsure, say N here.
5aef51c3
AL
1204
1205config VM86
b03b016f
KK
1206 bool
1207 default X86_LEGACY_VM86
34273f41
PA
1208
1209config X86_16BIT
1210 bool "Enable support for 16-bit segments" if EXPERT
1211 default y
a5b9e5a2 1212 depends on MODIFY_LDT_SYSCALL
a7f7f624 1213 help
34273f41
PA
1214 This option is required by programs like Wine to run 16-bit
1215 protected mode legacy code on x86 processors. Disabling
1216 this option saves about 300 bytes on i386, or around 6K text
1217 plus 16K runtime memory on x86-64,
1218
1219config X86_ESPFIX32
1220 def_bool y
1221 depends on X86_16BIT && X86_32
506f1d07 1222
197725de
PA
1223config X86_ESPFIX64
1224 def_bool y
34273f41 1225 depends on X86_16BIT && X86_64
506f1d07 1226
1ad83c85 1227config X86_VSYSCALL_EMULATION
b03b016f
KK
1228 bool "Enable vsyscall emulation" if EXPERT
1229 default y
1230 depends on X86_64
a7f7f624 1231 help
1ad83c85
AL
1232 This enables emulation of the legacy vsyscall page. Disabling
1233 it is roughly equivalent to booting with vsyscall=none, except
1234 that it will also disable the helpful warning if a program
1235 tries to use a vsyscall. With this option set to N, offending
1236 programs will just segfault, citing addresses of the form
1237 0xffffffffff600?00.
1238
1239 This option is required by many programs built before 2013, and
1240 care should be used even with newer programs if set to N.
1241
1242 Disabling this option saves about 7K of kernel size and
1243 possibly 4K of additional runtime pagetable memory.
1244
111e7b15
TG
1245config X86_IOPL_IOPERM
1246 bool "IOPERM and IOPL Emulation"
a24ca997 1247 default y
a7f7f624 1248 help
111e7b15
TG
1249 This enables the ioperm() and iopl() syscalls which are necessary
1250 for legacy applications.
1251
c8137ace
TG
1252 Legacy IOPL support is an overbroad mechanism which allows user
1253 space aside of accessing all 65536 I/O ports also to disable
1254 interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1255 capabilities and permission from potentially active security
1256 modules.
1257
1258 The emulation restricts the functionality of the syscall to
1259 only allowing the full range I/O port access, but prevents the
a24ca997
TG
1260 ability to disable interrupts from user space which would be
1261 granted if the hardware IOPL mechanism would be used.
c8137ace 1262
506f1d07
SR
1263config TOSHIBA
1264 tristate "Toshiba Laptop support"
1265 depends on X86_32
a7f7f624 1266 help
506f1d07
SR
1267 This adds a driver to safely access the System Management Mode of
1268 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1269 not work on models with a Phoenix BIOS. The System Management Mode
1270 is used to set the BIOS and power saving options on Toshiba portables.
1271
1272 For information on utilities to make use of this driver see the
1273 Toshiba Linux utilities web site at:
1274 <http://www.buzzard.org.uk/toshiba/>.
1275
1276 Say Y if you intend to run this kernel on a Toshiba portable.
1277 Say N otherwise.
1278
1279config I8K
039ae585 1280 tristate "Dell i8k legacy laptop support"
ef775a0e
RD
1281 depends on HWMON
1282 depends on PROC_FS
039ae585 1283 select SENSORS_DELL_SMM
a7f7f624 1284 help
039ae585
PR
1285 This option enables legacy /proc/i8k userspace interface in hwmon
1286 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1287 temperature and allows controlling fan speeds of Dell laptops via
1288 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1289 it reports also power and hotkey status. For fan speed control is
1290 needed userspace package i8kutils.
1291
1292 Say Y if you intend to run this kernel on old Dell laptops or want to
1293 use userspace package i8kutils.
506f1d07
SR
1294 Say N otherwise.
1295
1296config X86_REBOOTFIXUPS
9ba16087
JB
1297 bool "Enable X86 board specific fixups for reboot"
1298 depends on X86_32
a7f7f624 1299 help
506f1d07
SR
1300 This enables chipset and/or board specific fixups to be done
1301 in order to get reboot to work correctly. This is only needed on
1302 some combinations of hardware and BIOS. The symptom, for which
1303 this config is intended, is when reboot ends with a stalled/hung
1304 system.
1305
1306 Currently, the only fixup is for the Geode machines using
5e3a77e9 1307 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
506f1d07
SR
1308
1309 Say Y if you want to enable the fixup. Currently, it's safe to
1310 enable this option even if you don't need it.
1311 Say N otherwise.
1312
1313config MICROCODE
9a2bc335
BP
1314 bool "CPU microcode loading support"
1315 default y
80030e3d 1316 depends on CPU_SUP_AMD || CPU_SUP_INTEL
a7f7f624 1317 help
506f1d07 1318 If you say Y here, you will be able to update the microcode on
5f9c01aa
BP
1319 Intel and AMD processors. The Intel support is for the IA32 family,
1320 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1321 AMD support is for families 0x10 and later. You will obviously need
1322 the actual microcode binary data itself which is not shipped with
1323 the Linux kernel.
1324
1325 The preferred method to load microcode from a detached initrd is described
cb1aaebe 1326 in Documentation/x86/microcode.rst. For that you need to enable
5f9c01aa
BP
1327 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1328 initrd for microcode blobs.
1329
c508c46e
BG
1330 In addition, you can build the microcode into the kernel. For that you
1331 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1332 config option.
506f1d07 1333
8d86f390 1334config MICROCODE_INTEL
e43f6e67 1335 bool "Intel microcode loading support"
8f9ca475
IM
1336 depends on MICROCODE
1337 default MICROCODE
a7f7f624 1338 help
8f9ca475
IM
1339 This options enables microcode patch loading support for Intel
1340 processors.
1341
b8989db9
A
1342 For the current Intel microcode data package go to
1343 <https://downloadcenter.intel.com> and search for
1344 'Linux Processor Microcode Data File'.
8d86f390 1345
80cc9f10 1346config MICROCODE_AMD
e43f6e67 1347 bool "AMD microcode loading support"
8f9ca475 1348 depends on MICROCODE
a7f7f624 1349 help
8f9ca475
IM
1350 If you select this option, microcode patch loading support for AMD
1351 processors will be enabled.
80cc9f10 1352
8f9ca475 1353config MICROCODE_OLD_INTERFACE
c02f48e0
BP
1354 bool "Ancient loading interface (DEPRECATED)"
1355 default n
506f1d07 1356 depends on MICROCODE
a7f7f624 1357 help
c02f48e0
BP
1358 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1359 which was used by userspace tools like iucode_tool and microcode.ctl.
1360 It is inadequate because it runs too late to be able to properly
1361 load microcode on a machine and it needs special tools. Instead, you
1362 should've switched to the early loading method with the initrd or
cb1aaebe 1363 builtin microcode by now: Documentation/x86/microcode.rst
506f1d07
SR
1364
1365config X86_MSR
1366 tristate "/dev/cpu/*/msr - Model-specific register support"
a7f7f624 1367 help
506f1d07
SR
1368 This device gives privileged processes access to the x86
1369 Model-Specific Registers (MSRs). It is a character device with
1370 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1371 MSR accesses are directed to a specific CPU on multi-processor
1372 systems.
1373
1374config X86_CPUID
1375 tristate "/dev/cpu/*/cpuid - CPU information support"
a7f7f624 1376 help
506f1d07
SR
1377 This device gives processes access to the x86 CPUID instruction to
1378 be executed on a specific processor. It is a character device
1379 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1380 /dev/cpu/31/cpuid.
1381
1382choice
1383 prompt "High Memory Support"
6fc108a0 1384 default HIGHMEM4G
506f1d07
SR
1385 depends on X86_32
1386
1387config NOHIGHMEM
1388 bool "off"
a7f7f624 1389 help
506f1d07
SR
1390 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1391 However, the address space of 32-bit x86 processors is only 4
1392 Gigabytes large. That means that, if you have a large amount of
1393 physical memory, not all of it can be "permanently mapped" by the
1394 kernel. The physical memory that's not permanently mapped is called
1395 "high memory".
1396
1397 If you are compiling a kernel which will never run on a machine with
1398 more than 1 Gigabyte total physical RAM, answer "off" here (default
1399 choice and suitable for most users). This will result in a "3GB/1GB"
1400 split: 3GB are mapped so that each process sees a 3GB virtual memory
1401 space and the remaining part of the 4GB virtual memory space is used
1402 by the kernel to permanently map as much physical memory as
1403 possible.
1404
1405 If the machine has between 1 and 4 Gigabytes physical RAM, then
1406 answer "4GB" here.
1407
1408 If more than 4 Gigabytes is used then answer "64GB" here. This
1409 selection turns Intel PAE (Physical Address Extension) mode on.
1410 PAE implements 3-level paging on IA32 processors. PAE is fully
1411 supported by Linux, PAE mode is implemented on all recent Intel
1412 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1413 then the kernel will not boot on CPUs that don't support PAE!
1414
1415 The actual amount of total physical memory will either be
1416 auto detected or can be forced by using a kernel command line option
1417 such as "mem=256M". (Try "man bootparam" or see the documentation of
1418 your boot loader (lilo or loadlin) about how to pass options to the
1419 kernel at boot time.)
1420
1421 If unsure, say "off".
1422
1423config HIGHMEM4G
1424 bool "4GB"
a7f7f624 1425 help
506f1d07
SR
1426 Select this if you have a 32-bit processor and between 1 and 4
1427 gigabytes of physical RAM.
1428
1429config HIGHMEM64G
1430 bool "64GB"
225bac2d 1431 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
506f1d07 1432 select X86_PAE
a7f7f624 1433 help
506f1d07
SR
1434 Select this if you have a 32-bit processor and more than 4
1435 gigabytes of physical RAM.
1436
1437endchoice
1438
1439choice
6a108a14 1440 prompt "Memory split" if EXPERT
506f1d07
SR
1441 default VMSPLIT_3G
1442 depends on X86_32
a7f7f624 1443 help
506f1d07
SR
1444 Select the desired split between kernel and user memory.
1445
1446 If the address range available to the kernel is less than the
1447 physical memory installed, the remaining memory will be available
1448 as "high memory". Accessing high memory is a little more costly
1449 than low memory, as it needs to be mapped into the kernel first.
1450 Note that increasing the kernel address space limits the range
1451 available to user programs, making the address space there
1452 tighter. Selecting anything other than the default 3G/1G split
1453 will also likely make your kernel incompatible with binary-only
1454 kernel modules.
1455
1456 If you are not absolutely sure what you are doing, leave this
1457 option alone!
1458
1459 config VMSPLIT_3G
1460 bool "3G/1G user/kernel split"
1461 config VMSPLIT_3G_OPT
1462 depends on !X86_PAE
1463 bool "3G/1G user/kernel split (for full 1G low memory)"
1464 config VMSPLIT_2G
1465 bool "2G/2G user/kernel split"
1466 config VMSPLIT_2G_OPT
1467 depends on !X86_PAE
1468 bool "2G/2G user/kernel split (for full 2G low memory)"
1469 config VMSPLIT_1G
1470 bool "1G/3G user/kernel split"
1471endchoice
1472
1473config PAGE_OFFSET
1474 hex
1475 default 0xB0000000 if VMSPLIT_3G_OPT
1476 default 0x80000000 if VMSPLIT_2G
1477 default 0x78000000 if VMSPLIT_2G_OPT
1478 default 0x40000000 if VMSPLIT_1G
1479 default 0xC0000000
1480 depends on X86_32
1481
1482config HIGHMEM
3c2362e6 1483 def_bool y
506f1d07 1484 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
506f1d07
SR
1485
1486config X86_PAE
9ba16087 1487 bool "PAE (Physical Address Extension) Support"
506f1d07 1488 depends on X86_32 && !HIGHMEM4G
d4a451d5 1489 select PHYS_ADDR_T_64BIT
9d99c712 1490 select SWIOTLB
a7f7f624 1491 help
506f1d07
SR
1492 PAE is required for NX support, and furthermore enables
1493 larger swapspace support for non-overcommit purposes. It
1494 has the cost of more pagetable lookup overhead, and also
1495 consumes more pagetable space per process.
1496
77ef56e4
KS
1497config X86_5LEVEL
1498 bool "Enable 5-level page tables support"
18ec1eaf 1499 default y
eedb92ab 1500 select DYNAMIC_MEMORY_LAYOUT
162434e7 1501 select SPARSEMEM_VMEMMAP
77ef56e4 1502 depends on X86_64
a7f7f624 1503 help
77ef56e4
KS
1504 5-level paging enables access to larger address space:
1505 upto 128 PiB of virtual address space and 4 PiB of
1506 physical address space.
1507
1508 It will be supported by future Intel CPUs.
1509
6657fca0
KS
1510 A kernel with the option enabled can be booted on machines that
1511 support 4- or 5-level paging.
77ef56e4 1512
cb1aaebe 1513 See Documentation/x86/x86_64/5level-paging.rst for more
77ef56e4
KS
1514 information.
1515
1516 Say N if unsure.
1517
10971ab2 1518config X86_DIRECT_GBPAGES
e5008abe 1519 def_bool y
2e1da13f 1520 depends on X86_64
a7f7f624 1521 help
10971ab2
IM
1522 Certain kernel features effectively disable kernel
1523 linear 1 GB mappings (even if the CPU otherwise
1524 supports them), so don't confuse the user by printing
1525 that we have them enabled.
9e899816 1526
5c280cf6
TG
1527config X86_CPA_STATISTICS
1528 bool "Enable statistic for Change Page Attribute"
1529 depends on DEBUG_FS
a7f7f624 1530 help
b75baaf3 1531 Expose statistics about the Change Page Attribute mechanism, which
a943245a 1532 helps to determine the effectiveness of preserving large and huge
5c280cf6
TG
1533 page mappings when mapping protections are changed.
1534
20f07a04
KS
1535config X86_MEM_ENCRYPT
1536 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1537 select DYNAMIC_PHYSICAL_MASK
1538 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
1539 def_bool n
1540
7744ccdb
TL
1541config AMD_MEM_ENCRYPT
1542 bool "AMD Secure Memory Encryption (SME) support"
1543 depends on X86_64 && CPU_SUP_AMD
82fef0ad 1544 select DMA_COHERENT_POOL
ce9084ba 1545 select ARCH_USE_MEMREMAP_PROT
597cfe48 1546 select INSTRUCTION_DECODER
aa5a4611 1547 select ARCH_HAS_CC_PLATFORM
20f07a04 1548 select X86_MEM_ENCRYPT
a7f7f624 1549 help
7744ccdb
TL
1550 Say yes to enable support for the encryption of system memory.
1551 This requires an AMD processor that supports Secure Memory
1552 Encryption (SME).
1553
1554config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1555 bool "Activate AMD Secure Memory Encryption (SME) by default"
7744ccdb 1556 depends on AMD_MEM_ENCRYPT
a7f7f624 1557 help
7744ccdb
TL
1558 Say yes to have system memory encrypted by default if running on
1559 an AMD processor that supports Secure Memory Encryption (SME).
1560
1561 If set to Y, then the encryption of system memory can be
1562 deactivated with the mem_encrypt=off command line option.
1563
1564 If set to N, then the encryption of system memory can be
1565 activated with the mem_encrypt=on command line option.
1566
506f1d07
SR
1567# Common NUMA Features
1568config NUMA
e133f6ea 1569 bool "NUMA Memory Allocation and Scheduler Support"
506f1d07 1570 depends on SMP
b5660ba7
PA
1571 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1572 default y if X86_BIGSMP
7ecd19cf 1573 select USE_PERCPU_NUMA_NODE_ID
a7f7f624 1574 help
e133f6ea 1575 Enable NUMA (Non-Uniform Memory Access) support.
fd51b2d7 1576
506f1d07
SR
1577 The kernel will try to allocate memory used by a CPU on the
1578 local memory controller of the CPU and add some more
1579 NUMA awareness to the kernel.
1580
c280ea5e 1581 For 64-bit this is recommended if the system is Intel Core i7
fd51b2d7
KM
1582 (or later), AMD Opteron, or EM64T NUMA.
1583
b5660ba7 1584 For 32-bit this is only needed if you boot a 32-bit
7cf6c945 1585 kernel on a 64-bit NUMA platform.
fd51b2d7
KM
1586
1587 Otherwise, you should say N.
506f1d07 1588
eec1d4fa 1589config AMD_NUMA
3c2362e6
HH
1590 def_bool y
1591 prompt "Old style AMD Opteron NUMA detection"
5da0ef9a 1592 depends on X86_64 && NUMA && PCI
a7f7f624 1593 help
eec1d4fa
HR
1594 Enable AMD NUMA node topology detection. You should say Y here if
1595 you have a multi processor AMD system. This uses an old method to
1596 read the NUMA configuration directly from the builtin Northbridge
1597 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1598 which also takes priority if both are compiled in.
506f1d07
SR
1599
1600config X86_64_ACPI_NUMA
3c2362e6
HH
1601 def_bool y
1602 prompt "ACPI NUMA detection"
506f1d07
SR
1603 depends on X86_64 && NUMA && ACPI && PCI
1604 select ACPI_NUMA
a7f7f624 1605 help
506f1d07
SR
1606 Enable ACPI SRAT based node topology detection.
1607
1608config NUMA_EMU
1609 bool "NUMA emulation"
1b7e03ef 1610 depends on NUMA
a7f7f624 1611 help
506f1d07
SR
1612 Enable NUMA emulation. A flat machine will be split
1613 into virtual nodes when booted with "numa=fake=N", where N is the
1614 number of nodes. This is only useful for debugging.
1615
1616config NODES_SHIFT
d25e26b6 1617 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
51591e31
DR
1618 range 1 10
1619 default "10" if MAXSMP
506f1d07 1620 default "6" if X86_64
506f1d07 1621 default "3"
a9ee6cf5 1622 depends on NUMA
a7f7f624 1623 help
1184dc2f 1624 Specify the maximum number of NUMA Nodes available on the target
692105b8 1625 system. Increases memory reserved to accommodate various tables.
506f1d07 1626
506f1d07
SR
1627config ARCH_FLATMEM_ENABLE
1628 def_bool y
3b16651f 1629 depends on X86_32 && !NUMA
506f1d07 1630
506f1d07
SR
1631config ARCH_SPARSEMEM_ENABLE
1632 def_bool y
6ea30386 1633 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
506f1d07
SR
1634 select SPARSEMEM_STATIC if X86_32
1635 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1636
3b16651f 1637config ARCH_SPARSEMEM_DEFAULT
6ad57f7f 1638 def_bool X86_64 || (NUMA && X86_32)
3b16651f 1639
506f1d07
SR
1640config ARCH_SELECT_MEMORY_MODEL
1641 def_bool y
b263295d 1642 depends on ARCH_SPARSEMEM_ENABLE
506f1d07
SR
1643
1644config ARCH_MEMORY_PROBE
a0842b70 1645 bool "Enable sysfs memory/probe interface"
5c11f00b 1646 depends on MEMORY_HOTPLUG
a0842b70
TK
1647 help
1648 This option enables a sysfs memory/probe interface for testing.
cb1aaebe 1649 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
a0842b70 1650 If you are unsure how to answer this question, answer N.
506f1d07 1651
3b16651f
TH
1652config ARCH_PROC_KCORE_TEXT
1653 def_bool y
1654 depends on X86_64 && PROC_KCORE
1655
a29815a3 1656config ILLEGAL_POINTER_VALUE
b03b016f
KK
1657 hex
1658 default 0 if X86_32
1659 default 0xdead000000000000 if X86_64
a29815a3 1660
7a67832c
DW
1661config X86_PMEM_LEGACY_DEVICE
1662 bool
1663
ec776ef6 1664config X86_PMEM_LEGACY
7a67832c 1665 tristate "Support non-standard NVDIMMs and ADR protected memory"
9f53f9fa
DW
1666 depends on PHYS_ADDR_T_64BIT
1667 depends on BLK_DEV
7a67832c 1668 select X86_PMEM_LEGACY_DEVICE
7b27a862 1669 select NUMA_KEEP_MEMINFO if NUMA
9f53f9fa 1670 select LIBNVDIMM
ec776ef6
CH
1671 help
1672 Treat memory marked using the non-standard e820 type of 12 as used
1673 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1674 The kernel will offer these regions to the 'pmem' driver so
1675 they can be used for persistent storage.
1676
1677 Say Y if unsure.
1678
506f1d07
SR
1679config HIGHPTE
1680 bool "Allocate 3rd-level pagetables from highmem"
6fc108a0 1681 depends on HIGHMEM
a7f7f624 1682 help
506f1d07
SR
1683 The VM uses one page table entry for each page of physical memory.
1684 For systems with a lot of RAM, this can be wasteful of precious
1685 low memory. Setting this option will put user-space page table
1686 entries in high memory.
1687
9f077871 1688config X86_CHECK_BIOS_CORRUPTION
8f9ca475 1689 bool "Check for low memory corruption"
a7f7f624 1690 help
8f9ca475
IM
1691 Periodically check for memory corruption in low memory, which
1692 is suspected to be caused by BIOS. Even when enabled in the
1693 configuration, it is disabled at runtime. Enable it by
1694 setting "memory_corruption_check=1" on the kernel command
1695 line. By default it scans the low 64k of memory every 60
1696 seconds; see the memory_corruption_check_size and
1697 memory_corruption_check_period parameters in
8c27ceff 1698 Documentation/admin-guide/kernel-parameters.rst to adjust this.
8f9ca475
IM
1699
1700 When enabled with the default parameters, this option has
1701 almost no overhead, as it reserves a relatively small amount
1702 of memory and scans it infrequently. It both detects corruption
1703 and prevents it from affecting the running system.
1704
1705 It is, however, intended as a diagnostic tool; if repeatable
1706 BIOS-originated corruption always affects the same memory,
1707 you can use memmap= to prevent the kernel from using that
1708 memory.
9f077871 1709
c885df50 1710config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
8f9ca475 1711 bool "Set the default setting of memory_corruption_check"
c885df50
JF
1712 depends on X86_CHECK_BIOS_CORRUPTION
1713 default y
a7f7f624 1714 help
8f9ca475
IM
1715 Set whether the default state of memory_corruption_check is
1716 on or off.
c885df50 1717
506f1d07
SR
1718config MATH_EMULATION
1719 bool
a5b9e5a2 1720 depends on MODIFY_LDT_SYSCALL
87d6021b 1721 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
a7f7f624 1722 help
506f1d07
SR
1723 Linux can emulate a math coprocessor (used for floating point
1724 operations) if you don't have one. 486DX and Pentium processors have
1725 a math coprocessor built in, 486SX and 386 do not, unless you added
1726 a 487DX or 387, respectively. (The messages during boot time can
1727 give you some hints here ["man dmesg"].) Everyone needs either a
1728 coprocessor or this emulation.
1729
1730 If you don't have a math coprocessor, you need to say Y here; if you
1731 say Y here even though you have a coprocessor, the coprocessor will
1732 be used nevertheless. (This behavior can be changed with the kernel
1733 command line option "no387", which comes handy if your coprocessor
1734 is broken. Try "man bootparam" or see the documentation of your boot
1735 loader (lilo or loadlin) about how to pass options to the kernel at
1736 boot time.) This means that it is a good idea to say Y here if you
1737 intend to use this kernel on different machines.
1738
1739 More information about the internals of the Linux math coprocessor
1740 emulation can be found in <file:arch/x86/math-emu/README>.
1741
1742 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1743 kernel, it won't hurt.
1744
1745config MTRR
6fc108a0 1746 def_bool y
6a108a14 1747 prompt "MTRR (Memory Type Range Register) support" if EXPERT
a7f7f624 1748 help
506f1d07
SR
1749 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1750 the Memory Type Range Registers (MTRRs) may be used to control
1751 processor access to memory ranges. This is most useful if you have
1752 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1753 allows bus write transfers to be combined into a larger transfer
1754 before bursting over the PCI/AGP bus. This can increase performance
1755 of image write operations 2.5 times or more. Saying Y here creates a
1756 /proc/mtrr file which may be used to manipulate your processor's
1757 MTRRs. Typically the X server should use this.
1758
1759 This code has a reasonably generic interface so that similar
1760 control registers on other processors can be easily supported
1761 as well:
1762
1763 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1764 Registers (ARRs) which provide a similar functionality to MTRRs. For
1765 these, the ARRs are used to emulate the MTRRs.
1766 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1767 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1768 write-combining. All of these processors are supported by this code
1769 and it makes sense to say Y here if you have one of them.
1770
1771 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1772 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1773 can lead to all sorts of problems, so it's good to say Y here.
1774
1775 You can safely say Y even if your machine doesn't have MTRRs, you'll
1776 just add about 9 KB to your kernel.
1777
cb1aaebe 1778 See <file:Documentation/x86/mtrr.rst> for more information.
506f1d07 1779
95ffa243 1780config MTRR_SANITIZER
2ffb3501 1781 def_bool y
95ffa243
YL
1782 prompt "MTRR cleanup support"
1783 depends on MTRR
a7f7f624 1784 help
aba3728c
TG
1785 Convert MTRR layout from continuous to discrete, so X drivers can
1786 add writeback entries.
95ffa243 1787
aba3728c 1788 Can be disabled with disable_mtrr_cleanup on the kernel command line.
692105b8 1789 The largest mtrr entry size for a continuous block can be set with
aba3728c 1790 mtrr_chunk_size.
95ffa243 1791
2ffb3501 1792 If unsure, say Y.
95ffa243
YL
1793
1794config MTRR_SANITIZER_ENABLE_DEFAULT
f5098d62
YL
1795 int "MTRR cleanup enable value (0-1)"
1796 range 0 1
1797 default "0"
95ffa243 1798 depends on MTRR_SANITIZER
a7f7f624 1799 help
f5098d62 1800 Enable mtrr cleanup default value
95ffa243 1801
12031a62
YL
1802config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1803 int "MTRR cleanup spare reg num (0-7)"
1804 range 0 7
1805 default "1"
1806 depends on MTRR_SANITIZER
a7f7f624 1807 help
12031a62 1808 mtrr cleanup spare entries default, it can be changed via
aba3728c 1809 mtrr_spare_reg_nr=N on the kernel command line.
12031a62 1810
2e5d9c85 1811config X86_PAT
6fc108a0 1812 def_bool y
6a108a14 1813 prompt "x86 PAT support" if EXPERT
2a8a2719 1814 depends on MTRR
a7f7f624 1815 help
2e5d9c85 1816 Use PAT attributes to setup page level cache control.
042b78e4 1817
2e5d9c85 1818 PATs are the modern equivalents of MTRRs and are much more
1819 flexible than MTRRs.
1820
1821 Say N here if you see bootup problems (boot crash, boot hang,
042b78e4 1822 spontaneous reboots) or a non-working video driver.
2e5d9c85 1823
1824 If unsure, say Y.
1825
46cf98cd
VP
1826config ARCH_USES_PG_UNCACHED
1827 def_bool y
1828 depends on X86_PAT
1829
628c6246
PA
1830config ARCH_RANDOM
1831 def_bool y
1832 prompt "x86 architectural random number generator" if EXPERT
a7f7f624 1833 help
628c6246
PA
1834 Enable the x86 architectural RDRAND instruction
1835 (Intel Bull Mountain technology) to generate random numbers.
1836 If supported, this is a high bandwidth, cryptographically
1837 secure hardware random number generator.
1838
51ae4a2d
PA
1839config X86_SMAP
1840 def_bool y
1841 prompt "Supervisor Mode Access Prevention" if EXPERT
a7f7f624 1842 help
51ae4a2d
PA
1843 Supervisor Mode Access Prevention (SMAP) is a security
1844 feature in newer Intel processors. There is a small
1845 performance cost if this enabled and turned on; there is
1846 also a small increase in the kernel size if this is enabled.
1847
1848 If unsure, say Y.
1849
b971880f 1850config X86_UMIP
796ebc81 1851 def_bool y
b971880f 1852 prompt "User Mode Instruction Prevention" if EXPERT
a7f7f624 1853 help
b971880f
BM
1854 User Mode Instruction Prevention (UMIP) is a security feature in
1855 some x86 processors. If enabled, a general protection fault is
1856 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1857 executed in user mode. These instructions unnecessarily expose
1858 information about the hardware state.
796ebc81
RN
1859
1860 The vast majority of applications do not use these instructions.
1861 For the very few that do, software emulation is provided in
1862 specific cases in protected and virtual-8086 modes. Emulated
1863 results are dummy.
aa35f896 1864
35e97790 1865config X86_INTEL_MEMORY_PROTECTION_KEYS
38f3e775 1866 prompt "Memory Protection Keys"
35e97790 1867 def_bool y
284244a9 1868 # Note: only available in 64-bit mode
38f3e775 1869 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
52c8e601
IM
1870 select ARCH_USES_HIGH_VMA_FLAGS
1871 select ARCH_HAS_PKEYS
a7f7f624 1872 help
284244a9
DH
1873 Memory Protection Keys provides a mechanism for enforcing
1874 page-based protections, but without requiring modification of the
1875 page tables when an application changes protection domains.
1876
1eecbcdc 1877 For details, see Documentation/core-api/protection-keys.rst
284244a9
DH
1878
1879 If unsure, say y.
35e97790 1880
db616173
MH
1881choice
1882 prompt "TSX enable mode"
1883 depends on CPU_SUP_INTEL
1884 default X86_INTEL_TSX_MODE_OFF
1885 help
1886 Intel's TSX (Transactional Synchronization Extensions) feature
1887 allows to optimize locking protocols through lock elision which
1888 can lead to a noticeable performance boost.
1889
1890 On the other hand it has been shown that TSX can be exploited
1891 to form side channel attacks (e.g. TAA) and chances are there
1892 will be more of those attacks discovered in the future.
1893
1894 Therefore TSX is not enabled by default (aka tsx=off). An admin
1895 might override this decision by tsx=on the command line parameter.
1896 Even with TSX enabled, the kernel will attempt to enable the best
1897 possible TAA mitigation setting depending on the microcode available
1898 for the particular machine.
1899
1900 This option allows to set the default tsx mode between tsx=on, =off
1901 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1902 details.
1903
1904 Say off if not sure, auto if TSX is in use but it should be used on safe
1905 platforms or on if TSX is in use and the security aspect of tsx is not
1906 relevant.
1907
1908config X86_INTEL_TSX_MODE_OFF
1909 bool "off"
1910 help
1911 TSX is disabled if possible - equals to tsx=off command line parameter.
1912
1913config X86_INTEL_TSX_MODE_ON
1914 bool "on"
1915 help
1916 TSX is always enabled on TSX capable HW - equals the tsx=on command
1917 line parameter.
1918
1919config X86_INTEL_TSX_MODE_AUTO
1920 bool "auto"
1921 help
1922 TSX is enabled on TSX capable HW that is believed to be safe against
1923 side channel attacks- equals the tsx=auto command line parameter.
1924endchoice
1925
e7e05452
SC
1926config X86_SGX
1927 bool "Software Guard eXtensions (SGX)"
1928 depends on X86_64 && CPU_SUP_INTEL
1929 depends on CRYPTO=y
1930 depends on CRYPTO_SHA256=y
1931 select SRCU
1932 select MMU_NOTIFIER
901ddbb9 1933 select NUMA_KEEP_MEMINFO if NUMA
40e0e784 1934 select XARRAY_MULTI
e7e05452
SC
1935 help
1936 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1937 that can be used by applications to set aside private regions of code
1938 and data, referred to as enclaves. An enclave's private memory can
1939 only be accessed by code running within the enclave. Accesses from
1940 outside the enclave, including other enclaves, are disallowed by
1941 hardware.
1942
1943 If unsure, say N.
1944
506f1d07 1945config EFI
9ba16087 1946 bool "EFI runtime service support"
5b83683f 1947 depends on ACPI
f6ce5002 1948 select UCS2_STRING
022ee6c5 1949 select EFI_RUNTIME_WRAPPERS
1ff2fc02 1950 select ARCH_USE_MEMREMAP_PROT
a7f7f624 1951 help
8f9ca475
IM
1952 This enables the kernel to use EFI runtime services that are
1953 available (such as the EFI variable services).
506f1d07 1954
8f9ca475
IM
1955 This option is only useful on systems that have EFI firmware.
1956 In addition, you should use the latest ELILO loader available
1957 at <http://elilo.sourceforge.net> in order to take advantage
1958 of EFI runtime services. However, even with this option, the
1959 resultant kernel should continue to boot on existing non-EFI
1960 platforms.
506f1d07 1961
291f3632 1962config EFI_STUB
8f24f8c2 1963 bool "EFI stub support"
c6dbd3e5 1964 depends on EFI
8f24f8c2
AB
1965 depends on $(cc-option,-mabi=ms) || X86_32
1966 select RELOCATABLE
a7f7f624 1967 help
8f24f8c2 1968 This kernel feature allows a bzImage to be loaded directly
291f3632
MF
1969 by EFI firmware without the use of a bootloader.
1970
4f4cfa6c 1971 See Documentation/admin-guide/efi-stub.rst for more information.
0c759662 1972
7d453eee
MF
1973config EFI_MIXED
1974 bool "EFI mixed-mode support"
1975 depends on EFI_STUB && X86_64
a7f7f624 1976 help
7d453eee
MF
1977 Enabling this feature allows a 64-bit kernel to be booted
1978 on a 32-bit firmware, provided that your CPU supports 64-bit
1979 mode.
1980
1981 Note that it is not possible to boot a mixed-mode enabled
1982 kernel via the EFI boot stub - a bootloader that supports
1983 the EFI handover protocol must be used.
1984
1985 If unsure, say N.
1986
8636a1f9 1987source "kernel/Kconfig.hz"
506f1d07
SR
1988
1989config KEXEC
1990 bool "kexec system call"
2965faa5 1991 select KEXEC_CORE
a7f7f624 1992 help
506f1d07
SR
1993 kexec is a system call that implements the ability to shutdown your
1994 current kernel, and to start another kernel. It is like a reboot
1995 but it is independent of the system firmware. And like a reboot
1996 you can start any kernel with it, not just Linux.
1997
1998 The name comes from the similarity to the exec system call.
1999
2000 It is an ongoing process to be certain the hardware in a machine
2001 is properly shutdown, so do not be surprised if this code does not
bf220695
GU
2002 initially work for you. As of this writing the exact hardware
2003 interface is strongly in flux, so no good recommendation can be
2004 made.
506f1d07 2005
74ca317c
VG
2006config KEXEC_FILE
2007 bool "kexec file based system call"
2965faa5 2008 select KEXEC_CORE
74ca317c 2009 select BUILD_BIN2C
74ca317c
VG
2010 depends on X86_64
2011 depends on CRYPTO=y
2012 depends on CRYPTO_SHA256=y
a7f7f624 2013 help
74ca317c
VG
2014 This is new version of kexec system call. This system call is
2015 file based and takes file descriptors as system call argument
2016 for kernel and initramfs as opposed to list of segments as
2017 accepted by previous system call.
2018
b799a09f
AT
2019config ARCH_HAS_KEXEC_PURGATORY
2020 def_bool KEXEC_FILE
2021
99d5cadf 2022config KEXEC_SIG
8e7d8381 2023 bool "Verify kernel signature during kexec_file_load() syscall"
74ca317c 2024 depends on KEXEC_FILE
a7f7f624 2025 help
d8eb8940 2026
99d5cadf
JB
2027 This option makes the kexec_file_load() syscall check for a valid
2028 signature of the kernel image. The image can still be loaded without
2029 a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2030 there's a signature that we can check, then it must be valid.
2031
2032 In addition to this option, you need to enable signature
d8eb8940
BP
2033 verification for the corresponding kernel image type being
2034 loaded in order for this to work.
8e7d8381 2035
99d5cadf
JB
2036config KEXEC_SIG_FORCE
2037 bool "Require a valid signature in kexec_file_load() syscall"
2038 depends on KEXEC_SIG
a7f7f624 2039 help
99d5cadf
JB
2040 This option makes kernel signature verification mandatory for
2041 the kexec_file_load() syscall.
2042
8e7d8381
VG
2043config KEXEC_BZIMAGE_VERIFY_SIG
2044 bool "Enable bzImage signature verification support"
99d5cadf 2045 depends on KEXEC_SIG
8e7d8381
VG
2046 depends on SIGNED_PE_FILE_VERIFICATION
2047 select SYSTEM_TRUSTED_KEYRING
a7f7f624 2048 help
8e7d8381
VG
2049 Enable bzImage signature verification support.
2050
506f1d07 2051config CRASH_DUMP
04b69447 2052 bool "kernel crash dumps"
506f1d07 2053 depends on X86_64 || (X86_32 && HIGHMEM)
a7f7f624 2054 help
506f1d07
SR
2055 Generate crash dump after being started by kexec.
2056 This should be normally only set in special crash dump kernels
2057 which are loaded in the main kernel with kexec-tools into
2058 a specially reserved region and then later executed after
2059 a crash by kdump/kexec. The crash dump kernel must be compiled
2060 to a memory address not used by the main kernel or BIOS using
2061 PHYSICAL_START, or it must be built as a relocatable image
2062 (CONFIG_RELOCATABLE=y).
330d4810 2063 For more details see Documentation/admin-guide/kdump/kdump.rst
506f1d07 2064
3ab83521 2065config KEXEC_JUMP
6ea30386 2066 bool "kexec jump"
fee7b0d8 2067 depends on KEXEC && HIBERNATION
a7f7f624 2068 help
89081d17
YH
2069 Jump between original kernel and kexeced kernel and invoke
2070 code in physical address mode via KEXEC
3ab83521 2071
506f1d07 2072config PHYSICAL_START
6a108a14 2073 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
ceefccc9 2074 default "0x1000000"
a7f7f624 2075 help
506f1d07
SR
2076 This gives the physical address where the kernel is loaded.
2077
2078 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2079 bzImage will decompress itself to above physical address and
2080 run from there. Otherwise, bzImage will run from the address where
2081 it has been loaded by the boot loader and will ignore above physical
2082 address.
2083
2084 In normal kdump cases one does not have to set/change this option
2085 as now bzImage can be compiled as a completely relocatable image
2086 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2087 address. This option is mainly useful for the folks who don't want
2088 to use a bzImage for capturing the crash dump and want to use a
2089 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2090 to be specifically compiled to run from a specific memory area
2091 (normally a reserved region) and this option comes handy.
2092
ceefccc9
PA
2093 So if you are using bzImage for capturing the crash dump,
2094 leave the value here unchanged to 0x1000000 and set
2095 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2096 for capturing the crash dump change this value to start of
2097 the reserved region. In other words, it can be set based on
2098 the "X" value as specified in the "crashkernel=YM@XM"
2099 command line boot parameter passed to the panic-ed
330d4810 2100 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
ceefccc9 2101 for more details about crash dumps.
506f1d07
SR
2102
2103 Usage of bzImage for capturing the crash dump is recommended as
2104 one does not have to build two kernels. Same kernel can be used
2105 as production kernel and capture kernel. Above option should have
2106 gone away after relocatable bzImage support is introduced. But it
2107 is present because there are users out there who continue to use
2108 vmlinux for dump capture. This option should go away down the
2109 line.
2110
2111 Don't change this unless you know what you are doing.
2112
2113config RELOCATABLE
26717808
PA
2114 bool "Build a relocatable kernel"
2115 default y
a7f7f624 2116 help
506f1d07
SR
2117 This builds a kernel image that retains relocation information
2118 so it can be loaded someplace besides the default 1MB.
2119 The relocations tend to make the kernel binary about 10% larger,
2120 but are discarded at runtime.
2121
2122 One use is for the kexec on panic case where the recovery kernel
2123 must live at a different physical address than the primary
2124 kernel.
2125
2126 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2127 it has been loaded at and the compile time physical address
8ab3820f 2128 (CONFIG_PHYSICAL_START) is used as the minimum location.
506f1d07 2129
8ab3820f 2130config RANDOMIZE_BASE
e8581e3d 2131 bool "Randomize the address of the kernel image (KASLR)"
8ab3820f 2132 depends on RELOCATABLE
6807c846 2133 default y
a7f7f624 2134 help
e8581e3d
BH
2135 In support of Kernel Address Space Layout Randomization (KASLR),
2136 this randomizes the physical address at which the kernel image
2137 is decompressed and the virtual address where the kernel
2138 image is mapped, as a security feature that deters exploit
2139 attempts relying on knowledge of the location of kernel
2140 code internals.
2141
ed9f007e
KC
2142 On 64-bit, the kernel physical and virtual addresses are
2143 randomized separately. The physical address will be anywhere
2144 between 16MB and the top of physical memory (up to 64TB). The
2145 virtual address will be randomized from 16MB up to 1GB (9 bits
2146 of entropy). Note that this also reduces the memory space
2147 available to kernel modules from 1.5GB to 1GB.
2148
2149 On 32-bit, the kernel physical and virtual addresses are
2150 randomized together. They will be randomized from 16MB up to
2151 512MB (8 bits of entropy).
e8581e3d
BH
2152
2153 Entropy is generated using the RDRAND instruction if it is
2154 supported. If RDTSC is supported, its value is mixed into
2155 the entropy pool as well. If neither RDRAND nor RDTSC are
ed9f007e
KC
2156 supported, then entropy is read from the i8254 timer. The
2157 usable entropy is limited by the kernel being built using
2158 2GB addressing, and that PHYSICAL_ALIGN must be at a
2159 minimum of 2MB. As a result, only 10 bits of entropy are
2160 theoretically possible, but the implementations are further
2161 limited due to memory layouts.
e8581e3d 2162
6807c846 2163 If unsure, say Y.
8ab3820f
KC
2164
2165# Relocation on x86 needs some additional build support
845adf72
PA
2166config X86_NEED_RELOCS
2167 def_bool y
8ab3820f 2168 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
845adf72 2169
506f1d07 2170config PHYSICAL_ALIGN
a0215061 2171 hex "Alignment value to which kernel should be aligned"
8ab3820f 2172 default "0x200000"
a0215061
KC
2173 range 0x2000 0x1000000 if X86_32
2174 range 0x200000 0x1000000 if X86_64
a7f7f624 2175 help
506f1d07
SR
2176 This value puts the alignment restrictions on physical address
2177 where kernel is loaded and run from. Kernel is compiled for an
2178 address which meets above alignment restriction.
2179
2180 If bootloader loads the kernel at a non-aligned address and
2181 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2182 address aligned to above value and run from there.
2183
2184 If bootloader loads the kernel at a non-aligned address and
2185 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2186 load address and decompress itself to the address it has been
2187 compiled for and run from there. The address for which kernel is
2188 compiled already meets above alignment restrictions. Hence the
2189 end result is that kernel runs from a physical address meeting
2190 above alignment restrictions.
2191
a0215061
KC
2192 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2193 this value must be a multiple of 0x200000.
2194
506f1d07
SR
2195 Don't change this unless you know what you are doing.
2196
eedb92ab
KS
2197config DYNAMIC_MEMORY_LAYOUT
2198 bool
a7f7f624 2199 help
eedb92ab
KS
2200 This option makes base addresses of vmalloc and vmemmap as well as
2201 __PAGE_OFFSET movable during boot.
2202
0483e1fa
TG
2203config RANDOMIZE_MEMORY
2204 bool "Randomize the kernel memory sections"
2205 depends on X86_64
2206 depends on RANDOMIZE_BASE
eedb92ab 2207 select DYNAMIC_MEMORY_LAYOUT
0483e1fa 2208 default RANDOMIZE_BASE
a7f7f624 2209 help
0483e1fa
TG
2210 Randomizes the base virtual address of kernel memory sections
2211 (physical memory mapping, vmalloc & vmemmap). This security feature
2212 makes exploits relying on predictable memory locations less reliable.
2213
2214 The order of allocations remains unchanged. Entropy is generated in
2215 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2216 configuration have in average 30,000 different possible virtual
2217 addresses for each memory section.
2218
6807c846 2219 If unsure, say Y.
0483e1fa 2220
90397a41
TG
2221config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2222 hex "Physical memory mapping padding" if EXPERT
2223 depends on RANDOMIZE_MEMORY
2224 default "0xa" if MEMORY_HOTPLUG
2225 default "0x0"
2226 range 0x1 0x40 if MEMORY_HOTPLUG
2227 range 0x0 0x40
a7f7f624 2228 help
90397a41
TG
2229 Define the padding in terabytes added to the existing physical
2230 memory size during kernel memory randomization. It is useful
2231 for memory hotplug support but reduces the entropy available for
2232 address randomization.
2233
2234 If unsure, leave at the default value.
2235
506f1d07 2236config HOTPLUG_CPU
bebd024e 2237 def_bool y
40b31360 2238 depends on SMP
506f1d07 2239
80aa1dff
FY
2240config BOOTPARAM_HOTPLUG_CPU0
2241 bool "Set default setting of cpu0_hotpluggable"
2c922cd0 2242 depends on HOTPLUG_CPU
a7f7f624 2243 help
80aa1dff
FY
2244 Set whether default state of cpu0_hotpluggable is on or off.
2245
2246 Say Y here to enable CPU0 hotplug by default. If this switch
2247 is turned on, there is no need to give cpu0_hotplug kernel
2248 parameter and the CPU0 hotplug feature is enabled by default.
2249
2250 Please note: there are two known CPU0 dependencies if you want
2251 to enable the CPU0 hotplug feature either by this switch or by
2252 cpu0_hotplug kernel parameter.
2253
2254 First, resume from hibernate or suspend always starts from CPU0.
2255 So hibernate and suspend are prevented if CPU0 is offline.
2256
2257 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2258 offline if any interrupt can not migrate out of CPU0. There may
2259 be other CPU0 dependencies.
2260
2261 Please make sure the dependencies are under your control before
2262 you enable this feature.
2263
2264 Say N if you don't want to enable CPU0 hotplug feature by default.
2265 You still can enable the CPU0 hotplug feature at boot by kernel
2266 parameter cpu0_hotplug.
2267
a71c8bc5
FY
2268config DEBUG_HOTPLUG_CPU0
2269 def_bool n
2270 prompt "Debug CPU0 hotplug"
2c922cd0 2271 depends on HOTPLUG_CPU
a7f7f624 2272 help
a71c8bc5
FY
2273 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2274 soon as possible and boots up userspace with CPU0 offlined. User
2275 can online CPU0 back after boot time.
2276
2277 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2278 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2279 compilation or giving cpu0_hotplug kernel parameter at boot.
2280
2281 If unsure, say N.
2282
506f1d07 2283config COMPAT_VDSO
b0b49f26
AL
2284 def_bool n
2285 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
953fee1d 2286 depends on COMPAT_32
a7f7f624 2287 help
b0b49f26
AL
2288 Certain buggy versions of glibc will crash if they are
2289 presented with a 32-bit vDSO that is not mapped at the address
2290 indicated in its segment table.
e84446de 2291
b0b49f26
AL
2292 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2293 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2294 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2295 the only released version with the bug, but OpenSUSE 9
2296 contains a buggy "glibc 2.3.2".
506f1d07 2297
b0b49f26
AL
2298 The symptom of the bug is that everything crashes on startup, saying:
2299 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2300
2301 Saying Y here changes the default value of the vdso32 boot
2302 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2303 This works around the glibc bug but hurts performance.
2304
2305 If unsure, say N: if you are compiling your own kernel, you
2306 are unlikely to be using a buggy version of glibc.
506f1d07 2307
3dc33bd3
KC
2308choice
2309 prompt "vsyscall table for legacy applications"
2310 depends on X86_64
625b7b7f 2311 default LEGACY_VSYSCALL_XONLY
3dc33bd3
KC
2312 help
2313 Legacy user code that does not know how to find the vDSO expects
2314 to be able to issue three syscalls by calling fixed addresses in
2315 kernel space. Since this location is not randomized with ASLR,
2316 it can be used to assist security vulnerability exploitation.
2317
2318 This setting can be changed at boot time via the kernel command
bd49e16e 2319 line parameter vsyscall=[emulate|xonly|none].
3dc33bd3
KC
2320
2321 On a system with recent enough glibc (2.14 or newer) and no
2322 static binaries, you can say None without a performance penalty
2323 to improve security.
2324
bd49e16e 2325 If unsure, select "Emulate execution only".
3dc33bd3 2326
3dc33bd3 2327 config LEGACY_VSYSCALL_EMULATE
bd49e16e 2328 bool "Full emulation"
3dc33bd3 2329 help
bd49e16e
AL
2330 The kernel traps and emulates calls into the fixed vsyscall
2331 address mapping. This makes the mapping non-executable, but
2332 it still contains readable known contents, which could be
2333 used in certain rare security vulnerability exploits. This
2334 configuration is recommended when using legacy userspace
2335 that still uses vsyscalls along with legacy binary
2336 instrumentation tools that require code to be readable.
2337
2338 An example of this type of legacy userspace is running
2339 Pin on an old binary that still uses vsyscalls.
2340
2341 config LEGACY_VSYSCALL_XONLY
2342 bool "Emulate execution only"
2343 help
2344 The kernel traps and emulates calls into the fixed vsyscall
2345 address mapping and does not allow reads. This
2346 configuration is recommended when userspace might use the
2347 legacy vsyscall area but support for legacy binary
2348 instrumentation of legacy code is not needed. It mitigates
2349 certain uses of the vsyscall area as an ASLR-bypassing
2350 buffer.
3dc33bd3
KC
2351
2352 config LEGACY_VSYSCALL_NONE
2353 bool "None"
2354 help
2355 There will be no vsyscall mapping at all. This will
2356 eliminate any risk of ASLR bypass due to the vsyscall
2357 fixed address mapping. Attempts to use the vsyscalls
2358 will be reported to dmesg, so that either old or
2359 malicious userspace programs can be identified.
2360
2361endchoice
2362
516cbf37
TB
2363config CMDLINE_BOOL
2364 bool "Built-in kernel command line"
a7f7f624 2365 help
516cbf37
TB
2366 Allow for specifying boot arguments to the kernel at
2367 build time. On some systems (e.g. embedded ones), it is
2368 necessary or convenient to provide some or all of the
2369 kernel boot arguments with the kernel itself (that is,
2370 to not rely on the boot loader to provide them.)
2371
2372 To compile command line arguments into the kernel,
2373 set this option to 'Y', then fill in the
69711ca1 2374 boot arguments in CONFIG_CMDLINE.
516cbf37
TB
2375
2376 Systems with fully functional boot loaders (i.e. non-embedded)
2377 should leave this option set to 'N'.
2378
2379config CMDLINE
2380 string "Built-in kernel command string"
2381 depends on CMDLINE_BOOL
2382 default ""
a7f7f624 2383 help
516cbf37
TB
2384 Enter arguments here that should be compiled into the kernel
2385 image and used at boot time. If the boot loader provides a
2386 command line at boot time, it is appended to this string to
2387 form the full kernel command line, when the system boots.
2388
2389 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2390 change this behavior.
2391
2392 In most cases, the command line (whether built-in or provided
2393 by the boot loader) should specify the device for the root
2394 file system.
2395
2396config CMDLINE_OVERRIDE
2397 bool "Built-in command line overrides boot loader arguments"
645e6466 2398 depends on CMDLINE_BOOL && CMDLINE != ""
a7f7f624 2399 help
516cbf37
TB
2400 Set this option to 'Y' to have the kernel ignore the boot loader
2401 command line, and use ONLY the built-in command line.
2402
2403 This is used to work around broken boot loaders. This should
2404 be set to 'N' under normal conditions.
2405
a5b9e5a2
AL
2406config MODIFY_LDT_SYSCALL
2407 bool "Enable the LDT (local descriptor table)" if EXPERT
2408 default y
a7f7f624 2409 help
a5b9e5a2
AL
2410 Linux can allow user programs to install a per-process x86
2411 Local Descriptor Table (LDT) using the modify_ldt(2) system
2412 call. This is required to run 16-bit or segmented code such as
2413 DOSEMU or some Wine programs. It is also used by some very old
2414 threading libraries.
2415
2416 Enabling this feature adds a small amount of overhead to
2417 context switches and increases the low-level kernel attack
2418 surface. Disabling it removes the modify_ldt(2) system call.
2419
2420 Saying 'N' here may make sense for embedded or server kernels.
2421
3aac3ebe
TG
2422config STRICT_SIGALTSTACK_SIZE
2423 bool "Enforce strict size checking for sigaltstack"
2424 depends on DYNAMIC_SIGFRAME
2425 help
2426 For historical reasons MINSIGSTKSZ is a constant which became
2427 already too small with AVX512 support. Add a mechanism to
2428 enforce strict checking of the sigaltstack size against the
2429 real size of the FPU frame. This option enables the check
2430 by default. It can also be controlled via the kernel command
2431 line option 'strict_sas_size' independent of this config
2432 switch. Enabling it might break existing applications which
2433 allocate a too small sigaltstack but 'work' because they
2434 never get a signal delivered.
2435
2436 Say 'N' unless you want to really enforce this check.
2437
b700e7f0
SJ
2438source "kernel/livepatch/Kconfig"
2439
506f1d07
SR
2440endmenu
2441
3072e413
MH
2442config ARCH_HAS_ADD_PAGES
2443 def_bool y
5c11f00b 2444 depends on ARCH_ENABLE_MEMORY_HOTPLUG
3072e413 2445
f91ef222
OS
2446config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2447 def_bool y
2448
da85f865 2449menu "Power management and ACPI options"
e279b6c1
SR
2450
2451config ARCH_HIBERNATION_HEADER
3c2362e6 2452 def_bool y
44556530 2453 depends on HIBERNATION
e279b6c1
SR
2454
2455source "kernel/power/Kconfig"
2456
2457source "drivers/acpi/Kconfig"
2458
a6b68076 2459config X86_APM_BOOT
6fc108a0 2460 def_bool y
282e5aab 2461 depends on APM
a6b68076 2462
e279b6c1
SR
2463menuconfig APM
2464 tristate "APM (Advanced Power Management) BIOS support"
efefa6f6 2465 depends on X86_32 && PM_SLEEP
a7f7f624 2466 help
e279b6c1
SR
2467 APM is a BIOS specification for saving power using several different
2468 techniques. This is mostly useful for battery powered laptops with
2469 APM compliant BIOSes. If you say Y here, the system time will be
2470 reset after a RESUME operation, the /proc/apm device will provide
2471 battery status information, and user-space programs will receive
2472 notification of APM "events" (e.g. battery status change).
2473
2474 If you select "Y" here, you can disable actual use of the APM
2475 BIOS by passing the "apm=off" option to the kernel at boot time.
2476
2477 Note that the APM support is almost completely disabled for
2478 machines with more than one CPU.
2479
2480 In order to use APM, you will need supporting software. For location
151f4e2b 2481 and more information, read <file:Documentation/power/apm-acpi.rst>
2dc98fd3 2482 and the Battery Powered Linux mini-HOWTO, available from
e279b6c1
SR
2483 <http://www.tldp.org/docs.html#howto>.
2484
2485 This driver does not spin down disk drives (see the hdparm(8)
2486 manpage ("man 8 hdparm") for that), and it doesn't turn off
2487 VESA-compliant "green" monitors.
2488
2489 This driver does not support the TI 4000M TravelMate and the ACER
2490 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2491 desktop machines also don't have compliant BIOSes, and this driver
2492 may cause those machines to panic during the boot phase.
2493
2494 Generally, if you don't have a battery in your machine, there isn't
2495 much point in using this driver and you should say N. If you get
2496 random kernel OOPSes or reboots that don't seem to be related to
2497 anything, try disabling/enabling this option (or disabling/enabling
2498 APM in your BIOS).
2499
2500 Some other things you should try when experiencing seemingly random,
2501 "weird" problems:
2502
2503 1) make sure that you have enough swap space and that it is
2504 enabled.
2505 2) pass the "no-hlt" option to the kernel
2506 3) switch on floating point emulation in the kernel and pass
2507 the "no387" option to the kernel
2508 4) pass the "floppy=nodma" option to the kernel
2509 5) pass the "mem=4M" option to the kernel (thereby disabling
2510 all but the first 4 MB of RAM)
2511 6) make sure that the CPU is not over clocked.
2512 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2513 8) disable the cache from your BIOS settings
2514 9) install a fan for the video card or exchange video RAM
2515 10) install a better fan for the CPU
2516 11) exchange RAM chips
2517 12) exchange the motherboard.
2518
2519 To compile this driver as a module, choose M here: the
2520 module will be called apm.
2521
2522if APM
2523
2524config APM_IGNORE_USER_SUSPEND
2525 bool "Ignore USER SUSPEND"
a7f7f624 2526 help
e279b6c1
SR
2527 This option will ignore USER SUSPEND requests. On machines with a
2528 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2529 series notebooks, it is necessary to say Y because of a BIOS bug.
2530
2531config APM_DO_ENABLE
2532 bool "Enable PM at boot time"
a7f7f624 2533 help
e279b6c1
SR
2534 Enable APM features at boot time. From page 36 of the APM BIOS
2535 specification: "When disabled, the APM BIOS does not automatically
2536 power manage devices, enter the Standby State, enter the Suspend
2537 State, or take power saving steps in response to CPU Idle calls."
2538 This driver will make CPU Idle calls when Linux is idle (unless this
2539 feature is turned off -- see "Do CPU IDLE calls", below). This
2540 should always save battery power, but more complicated APM features
2541 will be dependent on your BIOS implementation. You may need to turn
2542 this option off if your computer hangs at boot time when using APM
2543 support, or if it beeps continuously instead of suspending. Turn
2544 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2545 T400CDT. This is off by default since most machines do fine without
2546 this feature.
2547
2548config APM_CPU_IDLE
dd8af076 2549 depends on CPU_IDLE
e279b6c1 2550 bool "Make CPU Idle calls when idle"
a7f7f624 2551 help
e279b6c1
SR
2552 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2553 On some machines, this can activate improved power savings, such as
2554 a slowed CPU clock rate, when the machine is idle. These idle calls
2555 are made after the idle loop has run for some length of time (e.g.,
2556 333 mS). On some machines, this will cause a hang at boot time or
2557 whenever the CPU becomes idle. (On machines with more than one CPU,
2558 this option does nothing.)
2559
2560config APM_DISPLAY_BLANK
2561 bool "Enable console blanking using APM"
a7f7f624 2562 help
e279b6c1
SR
2563 Enable console blanking using the APM. Some laptops can use this to
2564 turn off the LCD backlight when the screen blanker of the Linux
2565 virtual console blanks the screen. Note that this is only used by
2566 the virtual console screen blanker, and won't turn off the backlight
2567 when using the X Window system. This also doesn't have anything to
2568 do with your VESA-compliant power-saving monitor. Further, this
2569 option doesn't work for all laptops -- it might not turn off your
2570 backlight at all, or it might print a lot of errors to the console,
2571 especially if you are using gpm.
2572
2573config APM_ALLOW_INTS
2574 bool "Allow interrupts during APM BIOS calls"
a7f7f624 2575 help
e279b6c1
SR
2576 Normally we disable external interrupts while we are making calls to
2577 the APM BIOS as a measure to lessen the effects of a badly behaving
2578 BIOS implementation. The BIOS should reenable interrupts if it
2579 needs to. Unfortunately, some BIOSes do not -- especially those in
2580 many of the newer IBM Thinkpads. If you experience hangs when you
2581 suspend, try setting this to Y. Otherwise, say N.
2582
e279b6c1
SR
2583endif # APM
2584
bb0a56ec 2585source "drivers/cpufreq/Kconfig"
e279b6c1
SR
2586
2587source "drivers/cpuidle/Kconfig"
2588
27471fdb
AH
2589source "drivers/idle/Kconfig"
2590
e279b6c1
SR
2591endmenu
2592
2593
2594menu "Bus options (PCI etc.)"
2595
e279b6c1
SR
2596choice
2597 prompt "PCI access mode"
efefa6f6 2598 depends on X86_32 && PCI
e279b6c1 2599 default PCI_GOANY
a7f7f624 2600 help
e279b6c1
SR
2601 On PCI systems, the BIOS can be used to detect the PCI devices and
2602 determine their configuration. However, some old PCI motherboards
2603 have BIOS bugs and may crash if this is done. Also, some embedded
2604 PCI-based systems don't have any BIOS at all. Linux can also try to
2605 detect the PCI hardware directly without using the BIOS.
2606
2607 With this option, you can specify how Linux should detect the
2608 PCI devices. If you choose "BIOS", the BIOS will be used,
2609 if you choose "Direct", the BIOS won't be used, and if you
2610 choose "MMConfig", then PCI Express MMCONFIG will be used.
2611 If you choose "Any", the kernel will try MMCONFIG, then the
2612 direct access method and falls back to the BIOS if that doesn't
2613 work. If unsure, go with the default, which is "Any".
2614
2615config PCI_GOBIOS
2616 bool "BIOS"
2617
2618config PCI_GOMMCONFIG
2619 bool "MMConfig"
2620
2621config PCI_GODIRECT
2622 bool "Direct"
2623
3ef0e1f8 2624config PCI_GOOLPC
76fb6570 2625 bool "OLPC XO-1"
3ef0e1f8
AS
2626 depends on OLPC
2627
2bdd1b03
AS
2628config PCI_GOANY
2629 bool "Any"
2630
e279b6c1
SR
2631endchoice
2632
2633config PCI_BIOS
3c2362e6 2634 def_bool y
efefa6f6 2635 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
e279b6c1
SR
2636
2637# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2638config PCI_DIRECT
3c2362e6 2639 def_bool y
0aba496f 2640 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
e279b6c1
SR
2641
2642config PCI_MMCONFIG
b45c9f36
JK
2643 bool "Support mmconfig PCI config space access" if X86_64
2644 default y
4590d98f 2645 depends on PCI && (ACPI || JAILHOUSE_GUEST)
b45c9f36 2646 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
e279b6c1 2647
3ef0e1f8 2648config PCI_OLPC
2bdd1b03
AS
2649 def_bool y
2650 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
3ef0e1f8 2651
b5401a96
AN
2652config PCI_XEN
2653 def_bool y
2654 depends on PCI && XEN
b5401a96 2655
8364e1f8
JK
2656config MMCONF_FAM10H
2657 def_bool y
2658 depends on X86_64 && PCI_MMCONFIG && ACPI
e279b6c1 2659
3f6ea84a 2660config PCI_CNB20LE_QUIRK
6a108a14 2661 bool "Read CNB20LE Host Bridge Windows" if EXPERT
6ea30386 2662 depends on PCI
3f6ea84a
IS
2663 help
2664 Read the PCI windows out of the CNB20LE host bridge. This allows
2665 PCI hotplug to work on systems with the CNB20LE chipset which do
2666 not have ACPI.
2667
64a5fed6
BH
2668 There's no public spec for this chipset, and this functionality
2669 is known to be incomplete.
2670
2671 You should say N unless you know you need this.
2672
3a495511 2673config ISA_BUS
17a2a129 2674 bool "ISA bus support on modern systems" if EXPERT
3a495511 2675 help
17a2a129
WBG
2676 Expose ISA bus device drivers and options available for selection and
2677 configuration. Enable this option if your target machine has an ISA
2678 bus. ISA is an older system, displaced by PCI and newer bus
2679 architectures -- if your target machine is modern, it probably does
2680 not have an ISA bus.
3a495511
WBG
2681
2682 If unsure, say N.
2683
1c00f016 2684# x86_64 have no ISA slots, but can have ISA-style DMA.
e279b6c1 2685config ISA_DMA_API
1c00f016
DR
2686 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2687 default y
2688 help
2689 Enables ISA-style DMA support for devices requiring such controllers.
2690 If unsure, say Y.
e279b6c1 2691
51e68d05
LT
2692if X86_32
2693
e279b6c1
SR
2694config ISA
2695 bool "ISA support"
a7f7f624 2696 help
e279b6c1
SR
2697 Find out whether you have ISA slots on your motherboard. ISA is the
2698 name of a bus system, i.e. the way the CPU talks to the other stuff
2699 inside your box. Other bus systems are PCI, EISA, MicroChannel
2700 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2701 newer boards don't support it. If you have ISA, say Y, otherwise N.
2702
e279b6c1
SR
2703config SCx200
2704 tristate "NatSemi SCx200 support"
a7f7f624 2705 help
e279b6c1
SR
2706 This provides basic support for National Semiconductor's
2707 (now AMD's) Geode processors. The driver probes for the
2708 PCI-IDs of several on-chip devices, so its a good dependency
2709 for other scx200_* drivers.
2710
2711 If compiled as a module, the driver is named scx200.
2712
2713config SCx200HR_TIMER
2714 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
592913ec 2715 depends on SCx200
e279b6c1 2716 default y
a7f7f624 2717 help
e279b6c1
SR
2718 This driver provides a clocksource built upon the on-chip
2719 27MHz high-resolution timer. Its also a workaround for
2720 NSC Geode SC-1100's buggy TSC, which loses time when the
2721 processor goes idle (as is done by the scheduler). The
2722 other workaround is idle=poll boot option.
2723
3ef0e1f8
AS
2724config OLPC
2725 bool "One Laptop Per Child support"
54008979 2726 depends on !X86_PAE
3c554946 2727 select GPIOLIB
dc3119e7 2728 select OF
45bb1674 2729 select OF_PROMTREE
b4e51854 2730 select IRQ_DOMAIN
0c3d931b 2731 select OLPC_EC
a7f7f624 2732 help
3ef0e1f8
AS
2733 Add support for detecting the unique features of the OLPC
2734 XO hardware.
2735
a3128588
DD
2736config OLPC_XO1_PM
2737 bool "OLPC XO-1 Power Management"
fa112cf1 2738 depends on OLPC && MFD_CS5535=y && PM_SLEEP
a7f7f624 2739 help
97c4cb71 2740 Add support for poweroff and suspend of the OLPC XO-1 laptop.
bf1ebf00 2741
cfee9597
DD
2742config OLPC_XO1_RTC
2743 bool "OLPC XO-1 Real Time Clock"
2744 depends on OLPC_XO1_PM && RTC_DRV_CMOS
a7f7f624 2745 help
cfee9597
DD
2746 Add support for the XO-1 real time clock, which can be used as a
2747 programmable wakeup source.
2748
7feda8e9
DD
2749config OLPC_XO1_SCI
2750 bool "OLPC XO-1 SCI extras"
92e830f2 2751 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
ed8e47fe 2752 depends on INPUT=y
d8d01a63 2753 select POWER_SUPPLY
a7f7f624 2754 help
7feda8e9 2755 Add support for SCI-based features of the OLPC XO-1 laptop:
7bc74b3d 2756 - EC-driven system wakeups
7feda8e9 2757 - Power button
7bc74b3d 2758 - Ebook switch
2cf2baea 2759 - Lid switch
e1040ac6
DD
2760 - AC adapter status updates
2761 - Battery status updates
7feda8e9 2762
a0f30f59
DD
2763config OLPC_XO15_SCI
2764 bool "OLPC XO-1.5 SCI extras"
d8d01a63
DD
2765 depends on OLPC && ACPI
2766 select POWER_SUPPLY
a7f7f624 2767 help
a0f30f59
DD
2768 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2769 - EC-driven system wakeups
2770 - AC adapter status updates
2771 - Battery status updates
bf1ebf00 2772
d4f3e350
EW
2773config ALIX
2774 bool "PCEngines ALIX System Support (LED setup)"
2775 select GPIOLIB
a7f7f624 2776 help
d4f3e350
EW
2777 This option enables system support for the PCEngines ALIX.
2778 At present this just sets up LEDs for GPIO control on
2779 ALIX2/3/6 boards. However, other system specific setup should
2780 get added here.
2781
2782 Note: You must still enable the drivers for GPIO and LED support
2783 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2784
2785 Note: You have to set alix.force=1 for boards with Award BIOS.
2786
da4e3302
PP
2787config NET5501
2788 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2789 select GPIOLIB
a7f7f624 2790 help
da4e3302
PP
2791 This option enables system support for the Soekris Engineering net5501.
2792
3197059a
PP
2793config GEOS
2794 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2795 select GPIOLIB
2796 depends on DMI
a7f7f624 2797 help
3197059a
PP
2798 This option enables system support for the Traverse Technologies GEOS.
2799
7d029125
VD
2800config TS5500
2801 bool "Technologic Systems TS-5500 platform support"
2802 depends on MELAN
2803 select CHECK_SIGNATURE
2804 select NEW_LEDS
2805 select LEDS_CLASS
a7f7f624 2806 help
7d029125
VD
2807 This option enables system support for the Technologic Systems TS-5500.
2808
bc0120fd
SR
2809endif # X86_32
2810
23ac4ae8 2811config AMD_NB
e279b6c1 2812 def_bool y
0e152cd7 2813 depends on CPU_SUP_AMD && PCI
e279b6c1 2814
e279b6c1
SR
2815endmenu
2816
2817
1572497c 2818menu "Binary Emulations"
e279b6c1
SR
2819
2820config IA32_EMULATION
2821 bool "IA32 Emulation"
2822 depends on X86_64
39f88911 2823 select ARCH_WANT_OLD_COMPAT_IPC
d1603990 2824 select BINFMT_ELF
39f88911 2825 select COMPAT_OLD_SIGACTION
a7f7f624 2826 help
5fd92e65
L
2827 Include code to run legacy 32-bit programs under a
2828 64-bit kernel. You should likely turn this on, unless you're
2829 100% sure that you don't have any 32-bit programs left.
e279b6c1
SR
2830
2831config IA32_AOUT
8f9ca475
IM
2832 tristate "IA32 a.out support"
2833 depends on IA32_EMULATION
eac61655 2834 depends on BROKEN
a7f7f624 2835 help
8f9ca475 2836 Support old a.out binaries in the 32bit emulation.
e279b6c1 2837
0bf62763 2838config X86_X32
6ea30386 2839 bool "x32 ABI for 64-bit mode"
9b54050b 2840 depends on X86_64
a7f7f624 2841 help
5fd92e65
L
2842 Include code to run binaries for the x32 native 32-bit ABI
2843 for 64-bit processors. An x32 process gets access to the
2844 full 64-bit register file and wide data path while leaving
2845 pointers at 32 bits for smaller memory footprint.
2846
2847 You will need a recent binutils (2.22 or later) with
2848 elf32_x86_64 support enabled to compile a kernel with this
2849 option set.
2850
953fee1d
IM
2851config COMPAT_32
2852 def_bool y
2853 depends on IA32_EMULATION || X86_32
2854 select HAVE_UID16
2855 select OLD_SIGSUSPEND3
2856
e279b6c1 2857config COMPAT
3c2362e6 2858 def_bool y
0bf62763 2859 depends on IA32_EMULATION || X86_X32
e279b6c1 2860
3120e25e 2861if COMPAT
e279b6c1 2862config COMPAT_FOR_U64_ALIGNMENT
3120e25e 2863 def_bool y
e279b6c1
SR
2864
2865config SYSVIPC_COMPAT
3c2362e6 2866 def_bool y
3120e25e 2867 depends on SYSVIPC
3120e25e 2868endif
ee009e4a 2869
e279b6c1
SR
2870endmenu
2871
2872
e5beae16
KP
2873config HAVE_ATOMIC_IOMAP
2874 def_bool y
2875 depends on X86_32
2876
edf88417 2877source "arch/x86/kvm/Kconfig"
5e8ebd84
JD
2878
2879source "arch/x86/Kconfig.assembler"
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