x86/sgx: Add new sgx_epc_page flag bit to mark free pages
[linux-block.git] / arch / x86 / Kconfig
CommitLineData
b2441318 1# SPDX-License-Identifier: GPL-2.0
daa93fab
SR
2# Select 32 or 64 bit
3config 64BIT
104daea1
MY
4 bool "64-bit kernel" if "$(ARCH)" = "x86"
5 default "$(ARCH)" != "i386"
a7f7f624 6 help
daa93fab
SR
7 Say yes to build a 64-bit kernel - formerly known as x86_64
8 Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
3120e25e
JB
11 def_bool y
12 depends on !64BIT
341c787e
IM
13 # Options that are inherently 32-bit kernel only:
14 select ARCH_WANT_IPC_PARSE_VERSION
15 select CLKSRC_I8253
16 select CLONE_BACKWARDS
157e118b 17 select GENERIC_VDSO_32
117ed454 18 select HAVE_DEBUG_STACKOVERFLOW
157e118b 19 select KMAP_LOCAL
341c787e
IM
20 select MODULES_USE_ELF_REL
21 select OLD_SIGACTION
2ca408d9 22 select ARCH_SPLIT_ARG64
daa93fab
SR
23
24config X86_64
3120e25e
JB
25 def_bool y
26 depends on 64BIT
d94e0685 27 # Options that are inherently 64-bit kernel only:
4eb0716e 28 select ARCH_HAS_GIGANTIC_PAGE
c12d3362 29 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
d94e0685
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.
d94e0685
IM
49#
50# Arch settings
51#
52# ( Note that options that are marked 'if X86_64' could in principle be
53# ported to 32-bit as well. )
54#
8d5fffb9 55config X86
3c2362e6 56 def_bool y
c763ea26
IM
57 #
58 # Note: keep this list sorted alphabetically
59 #
6471b825
IM
60 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
61 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
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
0f1441b4 81 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION
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
6471b825
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
6471b825 107 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
14df3267 108 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096
583bfd48
NC
109 select ARCH_SUPPORTS_LTO_CLANG
110 select ARCH_SUPPORTS_LTO_CLANG_THIN
6471b825 111 select ARCH_USE_BUILTIN_BSWAP
dce44566 112 select ARCH_USE_MEMTEST
6471b825
IM
113 select ARCH_USE_QUEUED_RWLOCKS
114 select ARCH_USE_QUEUED_SPINLOCKS
2ce0d7f9 115 select ARCH_USE_SYM_ANNOTATIONS
ce4a4e56 116 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
81c22041 117 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64
c763ea26 118 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
51c2ee6d 119 select ARCH_WANTS_NO_INSTR
3876d4a3 120 select ARCH_WANT_HUGE_PMD_SHARE
59612b24 121 select ARCH_WANT_LD_ORPHAN_WARN
38d8b4e6 122 select ARCH_WANTS_THP_SWAP if X86_64
b5f06f64 123 select ARCH_HAS_PARANOID_L1D_FLUSH
10916706 124 select BUILDTIME_TABLE_SORT
6471b825 125 select CLKEVT_I8253
6471b825
IM
126 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
127 select CLOCKSOURCE_WATCHDOG
6471b825 128 select DCACHE_WORD_ACCESS
3aac3ebe 129 select DYNAMIC_SIGFRAME
45471cd9
LT
130 select EDAC_ATOMIC_SCRUB
131 select EDAC_SUPPORT
6471b825
IM
132 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
133 select GENERIC_CLOCKEVENTS_MIN_ADJUST
134 select GENERIC_CMOS_UPDATE
135 select GENERIC_CPU_AUTOPROBE
61dc0f55 136 select GENERIC_CPU_VULNERABILITIES
5b7c73e0 137 select GENERIC_EARLY_IOREMAP
27d6b4d1 138 select GENERIC_ENTRY
6471b825
IM
139 select GENERIC_FIND_FIRST_BIT
140 select GENERIC_IOMAP
c7d6c9dd 141 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
0fa115da 142 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
ad7a929f 143 select GENERIC_IRQ_MIGRATION if SMP
6471b825 144 select GENERIC_IRQ_PROBE
c201c917 145 select GENERIC_IRQ_RESERVATION_MODE
6471b825
IM
146 select GENERIC_IRQ_SHOW
147 select GENERIC_PENDING_IRQ if SMP
2ae27137 148 select GENERIC_PTDUMP
6471b825 149 select GENERIC_SMP_IDLE_THREAD
6471b825 150 select GENERIC_TIME_VSYSCALL
7ac87074 151 select GENERIC_GETTIMEOFDAY
550a77a7 152 select GENERIC_VDSO_TIME_NS
39656e83 153 select GUP_GET_PTE_LOW_HIGH if X86_PAE
17e5888e 154 select HARDIRQS_SW_RESEND
7edaeb68 155 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
6471b825
IM
156 select HAVE_ACPI_APEI if ACPI
157 select HAVE_ACPI_APEI_NMI if ACPI
158 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
6471b825
IM
159 select HAVE_ARCH_AUDITSYSCALL
160 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
161 select HAVE_ARCH_JUMP_LABEL
b34006c4 162 select HAVE_ARCH_JUMP_LABEL_RELATIVE
d17a1d97 163 select HAVE_ARCH_KASAN if X86_64
0609ae01 164 select HAVE_ARCH_KASAN_VMALLOC if X86_64
1dc0da6e 165 select HAVE_ARCH_KFENCE
6471b825 166 select HAVE_ARCH_KGDB
9e08f57d
DC
167 select HAVE_ARCH_MMAP_RND_BITS if MMU
168 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
1b028f78 169 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
271ca788 170 select HAVE_ARCH_PREL32_RELOCATIONS
6471b825 171 select HAVE_ARCH_SECCOMP_FILTER
f7d83c1c 172 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
afaef01c 173 select HAVE_ARCH_STACKLEAK
6471b825
IM
174 select HAVE_ARCH_TRACEHOOK
175 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
a00cc7d9 176 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
b64d8d1e 177 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
7677f7fd 178 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD
e37e43a4 179 select HAVE_ARCH_VMAP_STACK if X86_64
fe950f60 180 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
c763ea26 181 select HAVE_ARCH_WITHIN_STACK_FRAMES
2ff2b7ec 182 select HAVE_ASM_MODVERSIONS
6471b825
IM
183 select HAVE_CMPXCHG_DOUBLE
184 select HAVE_CMPXCHG_LOCAL
185 select HAVE_CONTEXT_TRACKING if X86_64
d1f250e2 186 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING
cf4db259 187 select HAVE_C_RECORDMCOUNT
6dafca97 188 select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION
6471b825 189 select HAVE_DEBUG_KMEMLEAK
6471b825 190 select HAVE_DMA_CONTIGUOUS
677aa9f7 191 select HAVE_DYNAMIC_FTRACE
06aeaaea 192 select HAVE_DYNAMIC_FTRACE_WITH_REGS
02a474ca 193 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64
562955fe 194 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
c316eb44 195 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64
0b707e57 196 select HAVE_SAMPLE_FTRACE_MULTI_DIRECT if X86_64
03f5781b 197 select HAVE_EBPF_JIT
58340a07 198 select HAVE_EFFICIENT_UNALIGNED_ACCESS
6630a8e5 199 select HAVE_EISA
5f56a5df 200 select HAVE_EXIT_THREAD
67a929e0 201 select HAVE_FAST_GUP
644e0e8d 202 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
6471b825 203 select HAVE_FTRACE_MCOUNT_RECORD
4a30e4c9 204 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE)
6471b825 205 select HAVE_FUNCTION_TRACER
6b90bd4b 206 select HAVE_GCC_PLUGINS
6471b825 207 select HAVE_HW_BREAKPOINT
6471b825 208 select HAVE_IOREMAP_PROT
624db9ea 209 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
6471b825 210 select HAVE_IRQ_TIME_ACCOUNTING
2e9f3bdd 211 select HAVE_KERNEL_BZIP2
6471b825
IM
212 select HAVE_KERNEL_GZIP
213 select HAVE_KERNEL_LZ4
2e9f3bdd 214 select HAVE_KERNEL_LZMA
13510997 215 select HAVE_KERNEL_LZO
6471b825 216 select HAVE_KERNEL_XZ
fb46d057 217 select HAVE_KERNEL_ZSTD
6471b825
IM
218 select HAVE_KPROBES
219 select HAVE_KPROBES_ON_FTRACE
540adea3 220 select HAVE_FUNCTION_ERROR_INJECTION
6471b825
IM
221 select HAVE_KRETPROBES
222 select HAVE_KVM
223 select HAVE_LIVEPATCH if X86_64
0102752e 224 select HAVE_MIXED_BREAKPOINTS_REGS
ee9f8fce 225 select HAVE_MOD_ARCH_SPECIFIC
9f132f7e 226 select HAVE_MOVE_PMD
be37c98d 227 select HAVE_MOVE_PUD
42a0bb3f 228 select HAVE_NMI
6471b825
IM
229 select HAVE_OPTPROBES
230 select HAVE_PCSPKR_PLATFORM
231 select HAVE_PERF_EVENTS
c01d4323 232 select HAVE_PERF_EVENTS_NMI
92e5aae4 233 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
eb01d42a 234 select HAVE_PCI
c5e63197 235 select HAVE_PERF_REGS
c5ebcedb 236 select HAVE_PERF_USER_STACK_DUMP
ff2e6d72 237 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
00998085 238 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
6471b825 239 select HAVE_REGS_AND_STACK_ACCESS_API
6415b38b 240 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
3c88ee19 241 select HAVE_FUNCTION_ARG_ACCESS_API
cd1a41ce 242 select HAVE_SOFTIRQ_ON_OWN_STACK
d148eac0 243 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
c763ea26 244 select HAVE_STACK_VALIDATION if X86_64
e6d6c071 245 select HAVE_STATIC_CALL
1e7e4788 246 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION
6ef869e0 247 select HAVE_PREEMPT_DYNAMIC
d6761b8f 248 select HAVE_RSEQ
6471b825 249 select HAVE_SYSCALL_TRACEPOINTS
6471b825 250 select HAVE_UNSTABLE_SCHED_CLOCK
7c68af6e 251 select HAVE_USER_RETURN_NOTIFIER
7ac87074 252 select HAVE_GENERIC_VDSO
05736e4a 253 select HOTPLUG_SMT if SMP
c0185808 254 select IRQ_FORCED_THREADING
86596f0a 255 select NEED_SG_DMA_LENGTH
2eac9c2d 256 select PCI_DOMAINS if PCI
625210cf 257 select PCI_LOCKLESS_CONFIG if PCI
6471b825 258 select PERF_EVENTS
3195ef59 259 select RTC_LIB
d6faca40 260 select RTC_MC146818_LIB
6471b825 261 select SPARSE_IRQ
83fe27ea 262 select SRCU
1e7e4788 263 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
6471b825 264 select SYSCTL_EXCEPTION_TRACE
15f4eae7 265 select THREAD_INFO_IN_TASK
4aae683f 266 select TRACE_IRQFLAGS_SUPPORT
6471b825
IM
267 select USER_STACKTRACE_SUPPORT
268 select VIRT_TO_BUS
3b02a051 269 select HAVE_ARCH_KCSAN if X86_64
6471b825 270 select X86_FEATURE_NAMES if PROC_FS
0c608dad 271 select PROC_PID_ARCH_STATUS if PROC_FS
9e2b4be3 272 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
7d8330a5 273
ba7e4d13 274config INSTRUCTION_DECODER
3120e25e
JB
275 def_bool y
276 depends on KPROBES || PERF_EVENTS || UPROBES
ba7e4d13 277
51b26ada
LT
278config OUTPUT_FORMAT
279 string
280 default "elf32-i386" if X86_32
281 default "elf64-x86-64" if X86_64
282
8d5fffb9 283config LOCKDEP_SUPPORT
3c2362e6 284 def_bool y
8d5fffb9
SR
285
286config STACKTRACE_SUPPORT
3c2362e6 287 def_bool y
8d5fffb9 288
8d5fffb9 289config MMU
3c2362e6 290 def_bool y
8d5fffb9 291
9e08f57d
DC
292config ARCH_MMAP_RND_BITS_MIN
293 default 28 if 64BIT
294 default 8
295
296config ARCH_MMAP_RND_BITS_MAX
297 default 32 if 64BIT
298 default 16
299
300config ARCH_MMAP_RND_COMPAT_BITS_MIN
301 default 8
302
303config ARCH_MMAP_RND_COMPAT_BITS_MAX
304 default 16
305
8d5fffb9
SR
306config SBUS
307 bool
308
309config GENERIC_ISA_DMA
3120e25e
JB
310 def_bool y
311 depends on ISA_DMA_API
8d5fffb9 312
8d5fffb9 313config GENERIC_BUG
3c2362e6 314 def_bool y
8d5fffb9 315 depends on BUG
b93a531e
JB
316 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
317
318config GENERIC_BUG_RELATIVE_POINTERS
319 bool
8d5fffb9 320
8d5fffb9 321config ARCH_MAY_HAVE_PC_FDC
3120e25e
JB
322 def_bool y
323 depends on ISA_DMA_API
8d5fffb9 324
1032c0ba
SR
325config GENERIC_CALIBRATE_DELAY
326 def_bool y
327
9a0b8415 328config ARCH_HAS_CPU_RELAX
329 def_bool y
330
316d097c
DH
331config ARCH_HAS_FILTER_PGPROT
332 def_bool y
333
dd5af90a 334config HAVE_SETUP_PER_CPU_AREA
89c9c4c5 335 def_bool y
b32ef636 336
08fc4580
TH
337config NEED_PER_CPU_EMBED_FIRST_CHUNK
338 def_bool y
339
340config NEED_PER_CPU_PAGE_FIRST_CHUNK
11124411
TH
341 def_bool y
342
801e4062
JB
343config ARCH_HIBERNATION_POSSIBLE
344 def_bool y
801e4062 345
d7109fe3
AS
346config ARCH_NR_GPIO
347 int
348 default 1024 if X86_64
349 default 512
350
f4cb5700
JB
351config ARCH_SUSPEND_POSSIBLE
352 def_bool y
f4cb5700 353
53313b2c
SC
354config ARCH_WANT_GENERAL_HUGETLB
355 def_bool y
356
8d5fffb9 357config AUDIT_ARCH
e0fd24a3 358 def_bool y if X86_64
8d5fffb9 359
d6f2d75a
AR
360config KASAN_SHADOW_OFFSET
361 hex
362 depends on KASAN
363 default 0xdffffc0000000000
364
69575d38
SW
365config HAVE_INTEL_TXT
366 def_bool y
6ea30386 367 depends on INTEL_IOMMU && ACPI
69575d38 368
6b0c3d44
SR
369config X86_32_SMP
370 def_bool y
371 depends on X86_32 && SMP
372
373config X86_64_SMP
374 def_bool y
375 depends on X86_64 && SMP
376
2b144498
SD
377config ARCH_SUPPORTS_UPROBES
378 def_bool y
379
d20642f0
RH
380config FIX_EARLYCON_MEM
381 def_bool y
382
94d49eb3
KS
383config DYNAMIC_PHYSICAL_MASK
384 bool
385
98233368
KS
386config PGTABLE_LEVELS
387 int
77ef56e4 388 default 5 if X86_5LEVEL
98233368
KS
389 default 4 if X86_64
390 default 3 if X86_PAE
391 default 2
392
2a61f474
MY
393config CC_HAS_SANE_STACKPROTECTOR
394 bool
395 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
396 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
397 help
398 We have to make sure stack protector is unconditionally disabled if
3fb0fdb3
AL
399 the compiler produces broken code or if it does not let us control
400 the segment on 32-bit kernels.
2a61f474 401
506f1d07
SR
402menu "Processor type and features"
403
506f1d07
SR
404config SMP
405 bool "Symmetric multi-processing support"
a7f7f624 406 help
506f1d07 407 This enables support for systems with more than one CPU. If you have
4a474157
RG
408 a system with only one CPU, say N. If you have a system with more
409 than one CPU, say Y.
506f1d07 410
4a474157 411 If you say N here, the kernel will run on uni- and multiprocessor
506f1d07
SR
412 machines, but will use only one CPU of a multiprocessor machine. If
413 you say Y here, the kernel will run on many, but not all,
4a474157 414 uniprocessor machines. On a uniprocessor machine, the kernel
506f1d07
SR
415 will run faster if you say N here.
416
417 Note that if you say Y here and choose architecture "586" or
418 "Pentium" under "Processor family", the kernel will not work on 486
419 architectures. Similarly, multiprocessor kernels for the "PPro"
420 architecture may not work on all Pentium based boards.
421
422 People using multiprocessor machines who say Y here should also say
423 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
424 Management" code will be disabled if you say Y here.
425
cb1aaebe 426 See also <file:Documentation/x86/i386/IO-APIC.rst>,
4f4cfa6c 427 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
506f1d07
SR
428 <http://www.tldp.org/docs.html#howto>.
429
430 If you don't know what to do here, say N.
431
9def39be
JT
432config X86_FEATURE_NAMES
433 bool "Processor feature human-readable names" if EMBEDDED
434 default y
a7f7f624 435 help
9def39be
JT
436 This option compiles in a table of x86 feature bits and corresponding
437 names. This is required to support /proc/cpuinfo and a few kernel
438 messages. You can disable this to save space, at the expense of
439 making those few kernel messages show numeric feature bits instead.
440
441 If in doubt, say Y.
442
06cd9a7d
YL
443config X86_X2APIC
444 bool "Support x2apic"
19e3d60d 445 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
a7f7f624 446 help
06cd9a7d
YL
447 This enables x2apic support on CPUs that have this feature.
448
449 This allows 32-bit apic IDs (so it can support very large systems),
450 and accesses the local apic via MSRs not via mmio.
451
06cd9a7d
YL
452 If you don't know what to do here, say N.
453
6695c85b 454config X86_MPPARSE
4590d98f 455 bool "Enable MPS table" if ACPI
7a527688 456 default y
5ab74722 457 depends on X86_LOCAL_APIC
a7f7f624 458 help
6695c85b
YL
459 For old smp systems that do not have proper acpi support. Newer systems
460 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
6695c85b 461
ddd70cf9 462config GOLDFISH
b03b016f
KK
463 def_bool y
464 depends on X86_GOLDFISH
ddd70cf9 465
76b04384
DW
466config RETPOLINE
467 bool "Avoid speculative indirect branches in kernel"
468 default y
469 help
470 Compile kernel with the retpoline compiler options to guard against
471 kernel-to-user data leaks by avoiding speculative indirect
472 branches. Requires a compiler with -mindirect-branch=thunk-extern
473 support for full protection. The kernel may run slower.
474
e6d42931
JW
475config X86_CPU_RESCTRL
476 bool "x86 CPU resource control support"
6fe07ce3 477 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
59fe5a77 478 select KERNFS
e79f15a4 479 select PROC_CPU_RESCTRL if PROC_FS
78e99b4a 480 help
e6d42931 481 Enable x86 CPU resource control support.
6fe07ce3
BM
482
483 Provide support for the allocation and monitoring of system resources
484 usage by the CPU.
485
486 Intel calls this Intel Resource Director Technology
487 (Intel(R) RDT). More information about RDT can be found in the
488 Intel x86 Architecture Software Developer Manual.
489
490 AMD calls this AMD Platform Quality of Service (AMD QoS).
491 More information about AMD QoS can be found in the AMD64 Technology
492 Platform Quality of Service Extensions manual.
78e99b4a
FY
493
494 Say N if unsure.
495
8425091f 496if X86_32
a0d0bb4d
RD
497config X86_BIGSMP
498 bool "Support for big SMP systems with more than 8 CPUs"
499 depends on SMP
a7f7f624 500 help
e133f6ea 501 This option is needed for the systems that have more than 8 CPUs.
a0d0bb4d 502
c5c606d9
RT
503config X86_EXTENDED_PLATFORM
504 bool "Support for extended (non-PC) x86 platforms"
505 default y
a7f7f624 506 help
06ac8346
IM
507 If you disable this option then the kernel will only support
508 standard PC platforms. (which covers the vast majority of
509 systems out there.)
510
8425091f
RT
511 If you enable this option then you'll be able to select support
512 for the following (non-PC) 32 bit x86 platforms:
cb7b8023 513 Goldfish (Android emulator)
8425091f 514 AMD Elan
8425091f
RT
515 RDC R-321x SoC
516 SGI 320/540 (Visual Workstation)
83125a3a 517 STA2X11-based (e.g. Northville)
3f4110a4 518 Moorestown MID devices
06ac8346
IM
519
520 If you have one of these systems, or if you want to build a
521 generic distribution kernel, say Y here - otherwise say N.
8425091f 522endif
06ac8346 523
8425091f
RT
524if X86_64
525config X86_EXTENDED_PLATFORM
526 bool "Support for extended (non-PC) x86 platforms"
527 default y
a7f7f624 528 help
8425091f
RT
529 If you disable this option then the kernel will only support
530 standard PC platforms. (which covers the vast majority of
531 systems out there.)
532
533 If you enable this option then you'll be able to select support
534 for the following (non-PC) 64 bit x86 platforms:
44b111b5 535 Numascale NumaChip
8425091f
RT
536 ScaleMP vSMP
537 SGI Ultraviolet
538
539 If you have one of these systems, or if you want to build a
540 generic distribution kernel, say Y here - otherwise say N.
541endif
c5c606d9
RT
542# This is an alphabetically sorted list of 64 bit extended platforms
543# Please maintain the alphabetic order if and when there are additions
44b111b5
SP
544config X86_NUMACHIP
545 bool "Numascale NumaChip"
546 depends on X86_64
547 depends on X86_EXTENDED_PLATFORM
548 depends on NUMA
549 depends on SMP
550 depends on X86_X2APIC
f9726bfd 551 depends on PCI_MMCONFIG
a7f7f624 552 help
44b111b5
SP
553 Adds support for Numascale NumaChip large-SMP systems. Needed to
554 enable more than ~168 cores.
555 If you don't have one of these, you should say N here.
506f1d07 556
c5c606d9
RT
557config X86_VSMP
558 bool "ScaleMP vSMP"
6276a074 559 select HYPERVISOR_GUEST
c5c606d9
RT
560 select PARAVIRT
561 depends on X86_64 && PCI
562 depends on X86_EXTENDED_PLATFORM
ead91d4b 563 depends on SMP
a7f7f624 564 help
c5c606d9
RT
565 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
566 supposed to run on these EM64T-based machines. Only choose this option
567 if you have one of these machines.
5e3a77e9 568
03b48632
NP
569config X86_UV
570 bool "SGI Ultraviolet"
571 depends on X86_64
c5c606d9 572 depends on X86_EXTENDED_PLATFORM
54c28d29 573 depends on NUMA
1ecb4ae5 574 depends on EFI
c2209ea5 575 depends on KEXEC_CORE
9d6c26e7 576 depends on X86_X2APIC
1222e564 577 depends on PCI
a7f7f624 578 help
03b48632
NP
579 This option is needed in order to support SGI Ultraviolet systems.
580 If you don't have one of these, you should say N here.
581
c5c606d9
RT
582# Following is an alphabetically sorted list of 32 bit extended platforms
583# Please maintain the alphabetic order if and when there are additions
506f1d07 584
ddd70cf9 585config X86_GOLDFISH
b03b016f
KK
586 bool "Goldfish (Virtual Platform)"
587 depends on X86_EXTENDED_PLATFORM
a7f7f624 588 help
ddd70cf9
JN
589 Enable support for the Goldfish virtual platform used primarily
590 for Android development. Unless you are building for the Android
591 Goldfish emulator say N here.
592
c751e17b
TG
593config X86_INTEL_CE
594 bool "CE4100 TV platform"
595 depends on PCI
596 depends on PCI_GODIRECT
6084a6e2 597 depends on X86_IO_APIC
c751e17b
TG
598 depends on X86_32
599 depends on X86_EXTENDED_PLATFORM
37bc9f50 600 select X86_REBOOTFIXUPS
da6b737b
SAS
601 select OF
602 select OF_EARLY_FLATTREE
a7f7f624 603 help
c751e17b
TG
604 Select for the Intel CE media processor (CE4100) SOC.
605 This option compiles in support for the CE4100 SOC for settop
606 boxes and media devices.
607
4cb9b00f 608config X86_INTEL_MID
43605ef1 609 bool "Intel MID platform support"
43605ef1 610 depends on X86_EXTENDED_PLATFORM
edc6bc78 611 depends on X86_PLATFORM_DEVICES
1ea7c673 612 depends on PCI
3fda5bb4 613 depends on X86_64 || (PCI_GOANY && X86_32)
1ea7c673 614 depends on X86_IO_APIC
4cb9b00f 615 select I2C
7c9c3a1e 616 select DW_APB_TIMER
54b34aa0 617 select INTEL_SCU_PCI
a7f7f624 618 help
4cb9b00f
DC
619 Select to build a kernel capable of supporting Intel MID (Mobile
620 Internet Device) platform systems which do not have the PCI legacy
621 interfaces. If you are building for a PC class system say N here.
1ea7c673 622
4cb9b00f
DC
623 Intel MID platforms are based on an Intel processor and chipset which
624 consume less power than most of the x86 derivatives.
43605ef1 625
8bbc2a13
BD
626config X86_INTEL_QUARK
627 bool "Intel Quark platform support"
628 depends on X86_32
629 depends on X86_EXTENDED_PLATFORM
630 depends on X86_PLATFORM_DEVICES
631 depends on X86_TSC
632 depends on PCI
633 depends on PCI_GOANY
634 depends on X86_IO_APIC
635 select IOSF_MBI
636 select INTEL_IMR
9ab6eb51 637 select COMMON_CLK
a7f7f624 638 help
8bbc2a13
BD
639 Select to include support for Quark X1000 SoC.
640 Say Y here if you have a Quark based system such as the Arduino
641 compatible Intel Galileo.
642
3d48aab1
MW
643config X86_INTEL_LPSS
644 bool "Intel Low Power Subsystem Support"
5962dd22 645 depends on X86 && ACPI && PCI
3d48aab1 646 select COMMON_CLK
0f531431 647 select PINCTRL
eebb3e8d 648 select IOSF_MBI
a7f7f624 649 help
3d48aab1
MW
650 Select to build support for Intel Low Power Subsystem such as
651 found on Intel Lynxpoint PCH. Selecting this option enables
0f531431
MN
652 things like clock tree (common clock framework) and pincontrol
653 which are needed by the LPSS peripheral drivers.
3d48aab1 654
92082a88
KX
655config X86_AMD_PLATFORM_DEVICE
656 bool "AMD ACPI2Platform devices support"
657 depends on ACPI
658 select COMMON_CLK
659 select PINCTRL
a7f7f624 660 help
92082a88
KX
661 Select to interpret AMD specific ACPI device to platform device
662 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
663 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
664 implemented under PINCTRL subsystem.
665
ced3ce76
DB
666config IOSF_MBI
667 tristate "Intel SoC IOSF Sideband support for SoC platforms"
668 depends on PCI
a7f7f624 669 help
ced3ce76
DB
670 This option enables sideband register access support for Intel SoC
671 platforms. On these platforms the IOSF sideband is used in lieu of
672 MSR's for some register accesses, mostly but not limited to thermal
673 and power. Drivers may query the availability of this device to
674 determine if they need the sideband in order to work on these
675 platforms. The sideband is available on the following SoC products.
676 This list is not meant to be exclusive.
677 - BayTrail
678 - Braswell
679 - Quark
680
681 You should say Y if you are running a kernel on one of these SoC's.
682
ed2226bd
DB
683config IOSF_MBI_DEBUG
684 bool "Enable IOSF sideband access through debugfs"
685 depends on IOSF_MBI && DEBUG_FS
a7f7f624 686 help
ed2226bd
DB
687 Select this option to expose the IOSF sideband access registers (MCR,
688 MDR, MCRX) through debugfs to write and read register information from
689 different units on the SoC. This is most useful for obtaining device
690 state information for debug and analysis. As this is a general access
691 mechanism, users of this option would have specific knowledge of the
692 device they want to access.
693
694 If you don't require the option or are in doubt, say N.
695
c5c606d9
RT
696config X86_RDC321X
697 bool "RDC R-321x SoC"
506f1d07 698 depends on X86_32
c5c606d9
RT
699 depends on X86_EXTENDED_PLATFORM
700 select M486
701 select X86_REBOOTFIXUPS
a7f7f624 702 help
c5c606d9
RT
703 This option is needed for RDC R-321x system-on-chip, also known
704 as R-8610-(G).
705 If you don't have one of these chips, you should say N here.
706
e0c7ae37 707config X86_32_NON_STANDARD
9c398017
IM
708 bool "Support non-standard 32-bit SMP architectures"
709 depends on X86_32 && SMP
c5c606d9 710 depends on X86_EXTENDED_PLATFORM
a7f7f624 711 help
b5660ba7
PA
712 This option compiles in the bigsmp and STA2X11 default
713 subarchitectures. It is intended for a generic binary
714 kernel. If you select them all, kernel will probe it one by
715 one and will fallback to default.
d49c4288 716
c5c606d9 717# Alphabetically sorted list of Non standard 32 bit platforms
d49c4288 718
d949f36f 719config X86_SUPPORTS_MEMORY_FAILURE
6fc108a0 720 def_bool y
d949f36f
LT
721 # MCE code calls memory_failure():
722 depends on X86_MCE
723 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
d949f36f
LT
724 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
725 depends on X86_64 || !SPARSEMEM
726 select ARCH_SUPPORTS_MEMORY_FAILURE
d949f36f 727
83125a3a
AR
728config STA2X11
729 bool "STA2X11 Companion Chip Support"
730 depends on X86_32_NON_STANDARD && PCI
83125a3a
AR
731 select SWIOTLB
732 select MFD_STA2X11
0145071b 733 select GPIOLIB
a7f7f624 734 help
83125a3a
AR
735 This adds support for boards based on the STA2X11 IO-Hub,
736 a.k.a. "ConneXt". The chip is used in place of the standard
737 PC chipset, so all "standard" peripherals are missing. If this
738 option is selected the kernel will still be able to boot on
739 standard PC machines.
740
82148d1d
S
741config X86_32_IRIS
742 tristate "Eurobraille/Iris poweroff module"
743 depends on X86_32
a7f7f624 744 help
82148d1d
S
745 The Iris machines from EuroBraille do not have APM or ACPI support
746 to shut themselves down properly. A special I/O sequence is
747 needed to do so, which is what this module does at
748 kernel shutdown.
749
750 This is only for Iris machines from EuroBraille.
751
752 If unused, say N.
753
ae1e9130 754config SCHED_OMIT_FRAME_POINTER
3c2362e6
HH
755 def_bool y
756 prompt "Single-depth WCHAN output"
a87d0914 757 depends on X86
a7f7f624 758 help
506f1d07
SR
759 Calculate simpler /proc/<PID>/wchan values. If this option
760 is disabled then wchan values will recurse back to the
761 caller function. This provides more accurate wchan values,
762 at the expense of slightly more scheduling overhead.
763
764 If in doubt, say "Y".
765
6276a074
BP
766menuconfig HYPERVISOR_GUEST
767 bool "Linux guest support"
a7f7f624 768 help
6276a074
BP
769 Say Y here to enable options for running Linux under various hyper-
770 visors. This option enables basic hypervisor detection and platform
771 setup.
506f1d07 772
6276a074
BP
773 If you say N, all options in this submenu will be skipped and
774 disabled, and Linux guest support won't be built in.
506f1d07 775
6276a074 776if HYPERVISOR_GUEST
506f1d07 777
e61bd94a
EPH
778config PARAVIRT
779 bool "Enable paravirtualization code"
a0e2bf7c 780 depends on HAVE_STATIC_CALL
a7f7f624 781 help
e61bd94a
EPH
782 This changes the kernel so it can modify itself when it is run
783 under a hypervisor, potentially improving performance significantly
784 over full virtualization. However, when run without a hypervisor
785 the kernel is theoretically slower and slightly larger.
786
c00a280a
JG
787config PARAVIRT_XXL
788 bool
789
6276a074
BP
790config PARAVIRT_DEBUG
791 bool "paravirt-ops debugging"
792 depends on PARAVIRT && DEBUG_KERNEL
a7f7f624 793 help
6276a074
BP
794 Enable to debug paravirt_ops internals. Specifically, BUG if
795 a paravirt_op is missing when it is called.
796
b4ecc126
JF
797config PARAVIRT_SPINLOCKS
798 bool "Paravirtualization layer for spinlocks"
6ea30386 799 depends on PARAVIRT && SMP
a7f7f624 800 help
b4ecc126
JF
801 Paravirtualized spinlocks allow a pvops backend to replace the
802 spinlock implementation with something virtualization-friendly
803 (for example, block the virtual CPU rather than spinning).
804
4c4e4f61
R
805 It has a minimal impact on native kernels and gives a nice performance
806 benefit on paravirtualized KVM / Xen kernels.
b4ecc126 807
4c4e4f61 808 If you are unsure how to answer this question, answer Y.
b4ecc126 809
ecca2502
ZY
810config X86_HV_CALLBACK_VECTOR
811 def_bool n
812
6276a074 813source "arch/x86/xen/Kconfig"
7af192c9 814
6276a074
BP
815config KVM_GUEST
816 bool "KVM Guest support (including kvmclock)"
817 depends on PARAVIRT
818 select PARAVIRT_CLOCK
a1c4423b 819 select ARCH_CPUIDLE_HALTPOLL
b1d40575 820 select X86_HV_CALLBACK_VECTOR
6276a074 821 default y
a7f7f624 822 help
6276a074
BP
823 This option enables various optimizations for running under the KVM
824 hypervisor. It includes a paravirtualized clock, so that instead
825 of relying on a PIT (or probably other) emulation by the
826 underlying device model, the host provides the guest with
827 timing infrastructure such as time of day, and system time
506f1d07 828
a1c4423b 829config ARCH_CPUIDLE_HALTPOLL
b03b016f
KK
830 def_bool n
831 prompt "Disable host haltpoll when loading haltpoll driver"
832 help
a1c4423b
MT
833 If virtualized under KVM, disable host haltpoll.
834
7733607f
MW
835config PVH
836 bool "Support for running PVH guests"
a7f7f624 837 help
7733607f
MW
838 This option enables the PVH entry point for guest virtual machines
839 as specified in the x86/HVM direct boot ABI.
840
6276a074
BP
841config PARAVIRT_TIME_ACCOUNTING
842 bool "Paravirtual steal time accounting"
843 depends on PARAVIRT
a7f7f624 844 help
6276a074
BP
845 Select this option to enable fine granularity task steal time
846 accounting. Time spent executing other tasks in parallel with
847 the current vCPU is discounted from the vCPU power. To account for
848 that, there can be a small performance impact.
849
850 If in doubt, say N here.
851
852config PARAVIRT_CLOCK
853 bool
97349135 854
4a362601
JK
855config JAILHOUSE_GUEST
856 bool "Jailhouse non-root cell support"
abde587b 857 depends on X86_64 && PCI
87e65d05 858 select X86_PM_TIMER
a7f7f624 859 help
4a362601
JK
860 This option allows to run Linux as guest in a Jailhouse non-root
861 cell. You can leave this option disabled if you only want to start
862 Jailhouse and run Linux afterwards in the root cell.
863
ec7972c9
ZY
864config ACRN_GUEST
865 bool "ACRN Guest support"
866 depends on X86_64
498ad393 867 select X86_HV_CALLBACK_VECTOR
ec7972c9
ZY
868 help
869 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
870 a flexible, lightweight reference open-source hypervisor, built with
871 real-time and safety-criticality in mind. It is built for embedded
872 IOT with small footprint and real-time features. More details can be
873 found in https://projectacrn.org/.
874
6276a074 875endif #HYPERVISOR_GUEST
97349135 876
506f1d07
SR
877source "arch/x86/Kconfig.cpu"
878
879config HPET_TIMER
3c2362e6 880 def_bool X86_64
506f1d07 881 prompt "HPET Timer Support" if X86_32
a7f7f624 882 help
8f9ca475
IM
883 Use the IA-PC HPET (High Precision Event Timer) to manage
884 time in preference to the PIT and RTC, if a HPET is
885 present.
886 HPET is the next generation timer replacing legacy 8254s.
887 The HPET provides a stable time base on SMP
888 systems, unlike the TSC, but it is more expensive to access,
4e7f9df2
MT
889 as it is off-chip. The interface used is documented
890 in the HPET spec, revision 1.
506f1d07 891
8f9ca475
IM
892 You can safely choose Y here. However, HPET will only be
893 activated if the platform and the BIOS support this feature.
894 Otherwise the 8254 will be used for timing services.
506f1d07 895
8f9ca475 896 Choose N to continue using the legacy 8254 timer.
506f1d07
SR
897
898config HPET_EMULATE_RTC
3c2362e6 899 def_bool y
3228e1dc 900 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
506f1d07 901
6a108a14 902# Mark as expert because too many people got it wrong.
506f1d07 903# The code disables itself when not needed.
7ae9392c
TP
904config DMI
905 default y
cf074402 906 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
6a108a14 907 bool "Enable DMI scanning" if EXPERT
a7f7f624 908 help
7ae9392c
TP
909 Enabled scanning of DMI to identify machine quirks. Say Y
910 here unless you have verified that your setup is not
911 affected by entries in the DMI blacklist. Required by PNP
912 BIOS code.
913
506f1d07 914config GART_IOMMU
38901f1c 915 bool "Old AMD GART IOMMU support"
2f9237d4 916 select DMA_OPS
a4ce5a48 917 select IOMMU_HELPER
506f1d07 918 select SWIOTLB
23ac4ae8 919 depends on X86_64 && PCI && AMD_NB
a7f7f624 920 help
ced3c42c
IM
921 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
922 GART based hardware IOMMUs.
923
924 The GART supports full DMA access for devices with 32-bit access
925 limitations, on systems with more than 3 GB. This is usually needed
926 for USB, sound, many IDE/SATA chipsets and some other devices.
927
928 Newer systems typically have a modern AMD IOMMU, supported via
929 the CONFIG_AMD_IOMMU=y config option.
930
931 In normal configurations this driver is only active when needed:
932 there's more than 3 GB of memory and the system contains a
933 32-bit limited device.
934
935 If unsure, say Y.
506f1d07 936
1184dc2f 937config MAXSMP
ddb0c5a6 938 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
6ea30386 939 depends on X86_64 && SMP && DEBUG_KERNEL
36f5101a 940 select CPUMASK_OFFSTACK
a7f7f624 941 help
ddb0c5a6 942 Enable maximum number of CPUS and NUMA Nodes for this architecture.
1184dc2f 943 If unsure, say N.
506f1d07 944
aec6487e
IM
945#
946# The maximum number of CPUs supported:
947#
948# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
949# and which can be configured interactively in the
950# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
951#
952# The ranges are different on 32-bit and 64-bit kernels, depending on
953# hardware capabilities and scalability features of the kernel.
954#
955# ( If MAXSMP is enabled we just use the highest possible value and disable
956# interactive configuration. )
957#
958
959config NR_CPUS_RANGE_BEGIN
a0d0bb4d 960 int
aec6487e
IM
961 default NR_CPUS_RANGE_END if MAXSMP
962 default 1 if !SMP
963 default 2
a0d0bb4d 964
aec6487e 965config NR_CPUS_RANGE_END
a0d0bb4d 966 int
aec6487e
IM
967 depends on X86_32
968 default 64 if SMP && X86_BIGSMP
969 default 8 if SMP && !X86_BIGSMP
970 default 1 if !SMP
a0d0bb4d 971
aec6487e 972config NR_CPUS_RANGE_END
a0d0bb4d 973 int
aec6487e 974 depends on X86_64
1edae1ae
SW
975 default 8192 if SMP && CPUMASK_OFFSTACK
976 default 512 if SMP && !CPUMASK_OFFSTACK
aec6487e 977 default 1 if !SMP
a0d0bb4d 978
aec6487e 979config NR_CPUS_DEFAULT
a0d0bb4d
RD
980 int
981 depends on X86_32
aec6487e
IM
982 default 32 if X86_BIGSMP
983 default 8 if SMP
984 default 1 if !SMP
a0d0bb4d 985
aec6487e 986config NR_CPUS_DEFAULT
a0d0bb4d
RD
987 int
988 depends on X86_64
aec6487e
IM
989 default 8192 if MAXSMP
990 default 64 if SMP
991 default 1 if !SMP
a0d0bb4d 992
506f1d07 993config NR_CPUS
36f5101a 994 int "Maximum number of CPUs" if SMP && !MAXSMP
aec6487e
IM
995 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
996 default NR_CPUS_DEFAULT
a7f7f624 997 help
506f1d07 998 This allows you to specify the maximum number of CPUs which this
bb61ccc7 999 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
cad14bb9 1000 supported value is 8192, otherwise the maximum value is 512. The
506f1d07
SR
1001 minimum value which makes sense is 2.
1002
aec6487e
IM
1003 This is purely to save memory: each supported CPU adds about 8KB
1004 to the kernel image.
506f1d07 1005
66558b73
TC
1006config SCHED_CLUSTER
1007 bool "Cluster scheduler support"
1008 depends on SMP
1009 default y
1010 help
1011 Cluster scheduler support improves the CPU scheduler's decision
1012 making when dealing with machines that have clusters of CPUs.
1013 Cluster usually means a couple of CPUs which are placed closely
1014 by sharing mid-level caches, last-level cache tags or internal
1015 busses.
1016
506f1d07 1017config SCHED_SMT
dbe73364 1018 def_bool y if SMP
506f1d07
SR
1019
1020config SCHED_MC
3c2362e6
HH
1021 def_bool y
1022 prompt "Multi-core scheduler support"
c8e56d20 1023 depends on SMP
a7f7f624 1024 help
506f1d07
SR
1025 Multi-core scheduler support improves the CPU scheduler's decision
1026 making when dealing with multi-core CPU chips at a cost of slightly
1027 increased overhead in some places. If unsure say N here.
1028
de966cf4
TC
1029config SCHED_MC_PRIO
1030 bool "CPU core priorities scheduler support"
0a21fc12
IM
1031 depends on SCHED_MC && CPU_SUP_INTEL
1032 select X86_INTEL_PSTATE
1033 select CPU_FREQ
de966cf4 1034 default y
a7f7f624 1035 help
0a21fc12
IM
1036 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1037 core ordering determined at manufacturing time, which allows
1038 certain cores to reach higher turbo frequencies (when running
1039 single threaded workloads) than others.
de966cf4 1040
0a21fc12
IM
1041 Enabling this kernel feature teaches the scheduler about
1042 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1043 scheduler's CPU selection logic accordingly, so that higher
1044 overall system performance can be achieved.
de966cf4 1045
0a21fc12 1046 This feature will have no effect on CPUs without this feature.
de966cf4 1047
0a21fc12 1048 If unsure say Y here.
5e76b2ab 1049
30b8b006 1050config UP_LATE_INIT
b03b016f
KK
1051 def_bool y
1052 depends on !SMP && X86_LOCAL_APIC
30b8b006 1053
506f1d07 1054config X86_UP_APIC
50849eef
JB
1055 bool "Local APIC support on uniprocessors" if !PCI_MSI
1056 default PCI_MSI
38a1dfda 1057 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
a7f7f624 1058 help
506f1d07
SR
1059 A local APIC (Advanced Programmable Interrupt Controller) is an
1060 integrated interrupt controller in the CPU. If you have a single-CPU
1061 system which has a processor with a local APIC, you can say Y here to
1062 enable and use it. If you say Y here even though your machine doesn't
1063 have a local APIC, then the kernel will still run with no slowdown at
1064 all. The local APIC supports CPU-generated self-interrupts (timer,
1065 performance counters), and the NMI watchdog which detects hard
1066 lockups.
1067
1068config X86_UP_IOAPIC
1069 bool "IO-APIC support on uniprocessors"
1070 depends on X86_UP_APIC
a7f7f624 1071 help
506f1d07
SR
1072 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1073 SMP-capable replacement for PC-style interrupt controllers. Most
1074 SMP systems and many recent uniprocessor systems have one.
1075
1076 If you have a single-CPU system with an IO-APIC, you can say Y here
1077 to use it. If you say Y here even though your machine doesn't have
1078 an IO-APIC, then the kernel will still run with no slowdown at all.
1079
1080config X86_LOCAL_APIC
3c2362e6 1081 def_bool y
0dbc6078 1082 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
b5dc8e6c 1083 select IRQ_DOMAIN_HIERARCHY
52f518a3 1084 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
506f1d07
SR
1085
1086config X86_IO_APIC
b1da1e71
JB
1087 def_bool y
1088 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
506f1d07 1089
41b9eb26
SA
1090config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1091 bool "Reroute for broken boot IRQs"
41b9eb26 1092 depends on X86_IO_APIC
a7f7f624 1093 help
41b9eb26
SA
1094 This option enables a workaround that fixes a source of
1095 spurious interrupts. This is recommended when threaded
1096 interrupt handling is used on systems where the generation of
1097 superfluous "boot interrupts" cannot be disabled.
1098
1099 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1100 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1101 kernel does during interrupt handling). On chipsets where this
1102 boot IRQ generation cannot be disabled, this workaround keeps
1103 the original IRQ line masked so that only the equivalent "boot
1104 IRQ" is delivered to the CPUs. The workaround also tells the
1105 kernel to set up the IRQ handler on the boot IRQ line. In this
1106 way only one interrupt is delivered to the kernel. Otherwise
1107 the spurious second interrupt may cause the kernel to bring
1108 down (vital) interrupt lines.
1109
1110 Only affects "broken" chipsets. Interrupt sharing may be
1111 increased on these systems.
1112
506f1d07 1113config X86_MCE
bab9bc65 1114 bool "Machine Check / overheating reporting"
648ed940 1115 select GENERIC_ALLOCATOR
e57dbaf7 1116 default y
a7f7f624 1117 help
bab9bc65
AK
1118 Machine Check support allows the processor to notify the
1119 kernel if it detects a problem (e.g. overheating, data corruption).
506f1d07 1120 The action the kernel takes depends on the severity of the problem,
bab9bc65 1121 ranging from warning messages to halting the machine.
4efc0670 1122
5de97c9f
TL
1123config X86_MCELOG_LEGACY
1124 bool "Support for deprecated /dev/mcelog character device"
1125 depends on X86_MCE
a7f7f624 1126 help
5de97c9f
TL
1127 Enable support for /dev/mcelog which is needed by the old mcelog
1128 userspace logging daemon. Consider switching to the new generation
1129 rasdaemon solution.
1130
506f1d07 1131config X86_MCE_INTEL
3c2362e6
HH
1132 def_bool y
1133 prompt "Intel MCE features"
c1ebf835 1134 depends on X86_MCE && X86_LOCAL_APIC
a7f7f624 1135 help
506f1d07
SR
1136 Additional support for intel specific MCE features such as
1137 the thermal monitor.
1138
1139config X86_MCE_AMD
3c2362e6
HH
1140 def_bool y
1141 prompt "AMD MCE features"
f5382de9 1142 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
a7f7f624 1143 help
506f1d07
SR
1144 Additional support for AMD specific MCE features such as
1145 the DRAM Error Threshold.
1146
4efc0670 1147config X86_ANCIENT_MCE
6fc108a0 1148 bool "Support for old Pentium 5 / WinChip machine checks"
c31d9633 1149 depends on X86_32 && X86_MCE
a7f7f624 1150 help
cd13adcc 1151 Include support for machine check handling on old Pentium 5 or WinChip
5065a706 1152 systems. These typically need to be enabled explicitly on the command
cd13adcc 1153 line.
4efc0670 1154
b2762686
AK
1155config X86_MCE_THRESHOLD
1156 depends on X86_MCE_AMD || X86_MCE_INTEL
6fc108a0 1157 def_bool y
b2762686 1158
ea149b36 1159config X86_MCE_INJECT
bc8e80d5 1160 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
ea149b36 1161 tristate "Machine check injector support"
a7f7f624 1162 help
ea149b36
AK
1163 Provide support for injecting machine checks for testing purposes.
1164 If you don't know what a machine check is and you don't do kernel
1165 QA it is safe to say n.
1166
07dc900e 1167source "arch/x86/events/Kconfig"
e633c65a 1168
5aef51c3 1169config X86_LEGACY_VM86
1e642812 1170 bool "Legacy VM86 support"
506f1d07 1171 depends on X86_32
a7f7f624 1172 help
5aef51c3
AL
1173 This option allows user programs to put the CPU into V8086
1174 mode, which is an 80286-era approximation of 16-bit real mode.
1175
1176 Some very old versions of X and/or vbetool require this option
1177 for user mode setting. Similarly, DOSEMU will use it if
1178 available to accelerate real mode DOS programs. However, any
1179 recent version of DOSEMU, X, or vbetool should be fully
1180 functional even without kernel VM86 support, as they will all
1e642812
IM
1181 fall back to software emulation. Nevertheless, if you are using
1182 a 16-bit DOS program where 16-bit performance matters, vm86
1183 mode might be faster than emulation and you might want to
1184 enable this option.
5aef51c3 1185
1e642812
IM
1186 Note that any app that works on a 64-bit kernel is unlikely to
1187 need this option, as 64-bit kernels don't, and can't, support
1188 V8086 mode. This option is also unrelated to 16-bit protected
1189 mode and is not needed to run most 16-bit programs under Wine.
5aef51c3 1190
1e642812
IM
1191 Enabling this option increases the complexity of the kernel
1192 and slows down exception handling a tiny bit.
5aef51c3 1193
1e642812 1194 If unsure, say N here.
5aef51c3
AL
1195
1196config VM86
b03b016f
KK
1197 bool
1198 default X86_LEGACY_VM86
34273f41
PA
1199
1200config X86_16BIT
1201 bool "Enable support for 16-bit segments" if EXPERT
1202 default y
a5b9e5a2 1203 depends on MODIFY_LDT_SYSCALL
a7f7f624 1204 help
34273f41
PA
1205 This option is required by programs like Wine to run 16-bit
1206 protected mode legacy code on x86 processors. Disabling
1207 this option saves about 300 bytes on i386, or around 6K text
1208 plus 16K runtime memory on x86-64,
1209
1210config X86_ESPFIX32
1211 def_bool y
1212 depends on X86_16BIT && X86_32
506f1d07 1213
197725de
PA
1214config X86_ESPFIX64
1215 def_bool y
34273f41 1216 depends on X86_16BIT && X86_64
506f1d07 1217
1ad83c85 1218config X86_VSYSCALL_EMULATION
b03b016f
KK
1219 bool "Enable vsyscall emulation" if EXPERT
1220 default y
1221 depends on X86_64
a7f7f624 1222 help
1ad83c85
AL
1223 This enables emulation of the legacy vsyscall page. Disabling
1224 it is roughly equivalent to booting with vsyscall=none, except
1225 that it will also disable the helpful warning if a program
1226 tries to use a vsyscall. With this option set to N, offending
1227 programs will just segfault, citing addresses of the form
1228 0xffffffffff600?00.
1229
1230 This option is required by many programs built before 2013, and
1231 care should be used even with newer programs if set to N.
1232
1233 Disabling this option saves about 7K of kernel size and
1234 possibly 4K of additional runtime pagetable memory.
1235
111e7b15
TG
1236config X86_IOPL_IOPERM
1237 bool "IOPERM and IOPL Emulation"
a24ca997 1238 default y
a7f7f624 1239 help
111e7b15
TG
1240 This enables the ioperm() and iopl() syscalls which are necessary
1241 for legacy applications.
1242
c8137ace
TG
1243 Legacy IOPL support is an overbroad mechanism which allows user
1244 space aside of accessing all 65536 I/O ports also to disable
1245 interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1246 capabilities and permission from potentially active security
1247 modules.
1248
1249 The emulation restricts the functionality of the syscall to
1250 only allowing the full range I/O port access, but prevents the
a24ca997
TG
1251 ability to disable interrupts from user space which would be
1252 granted if the hardware IOPL mechanism would be used.
c8137ace 1253
506f1d07
SR
1254config TOSHIBA
1255 tristate "Toshiba Laptop support"
1256 depends on X86_32
a7f7f624 1257 help
506f1d07
SR
1258 This adds a driver to safely access the System Management Mode of
1259 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1260 not work on models with a Phoenix BIOS. The System Management Mode
1261 is used to set the BIOS and power saving options on Toshiba portables.
1262
1263 For information on utilities to make use of this driver see the
1264 Toshiba Linux utilities web site at:
1265 <http://www.buzzard.org.uk/toshiba/>.
1266
1267 Say Y if you intend to run this kernel on a Toshiba portable.
1268 Say N otherwise.
1269
1270config I8K
039ae585 1271 tristate "Dell i8k legacy laptop support"
ef775a0e
RD
1272 depends on HWMON
1273 depends on PROC_FS
039ae585 1274 select SENSORS_DELL_SMM
a7f7f624 1275 help
039ae585
PR
1276 This option enables legacy /proc/i8k userspace interface in hwmon
1277 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1278 temperature and allows controlling fan speeds of Dell laptops via
1279 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1280 it reports also power and hotkey status. For fan speed control is
1281 needed userspace package i8kutils.
1282
1283 Say Y if you intend to run this kernel on old Dell laptops or want to
1284 use userspace package i8kutils.
506f1d07
SR
1285 Say N otherwise.
1286
1287config X86_REBOOTFIXUPS
9ba16087
JB
1288 bool "Enable X86 board specific fixups for reboot"
1289 depends on X86_32
a7f7f624 1290 help
506f1d07
SR
1291 This enables chipset and/or board specific fixups to be done
1292 in order to get reboot to work correctly. This is only needed on
1293 some combinations of hardware and BIOS. The symptom, for which
1294 this config is intended, is when reboot ends with a stalled/hung
1295 system.
1296
1297 Currently, the only fixup is for the Geode machines using
5e3a77e9 1298 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
506f1d07
SR
1299
1300 Say Y if you want to enable the fixup. Currently, it's safe to
1301 enable this option even if you don't need it.
1302 Say N otherwise.
1303
1304config MICROCODE
9a2bc335
BP
1305 bool "CPU microcode loading support"
1306 default y
80030e3d 1307 depends on CPU_SUP_AMD || CPU_SUP_INTEL
a7f7f624 1308 help
506f1d07 1309 If you say Y here, you will be able to update the microcode on
5f9c01aa
BP
1310 Intel and AMD processors. The Intel support is for the IA32 family,
1311 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1312 AMD support is for families 0x10 and later. You will obviously need
1313 the actual microcode binary data itself which is not shipped with
1314 the Linux kernel.
1315
1316 The preferred method to load microcode from a detached initrd is described
cb1aaebe 1317 in Documentation/x86/microcode.rst. For that you need to enable
5f9c01aa
BP
1318 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1319 initrd for microcode blobs.
1320
c508c46e
BG
1321 In addition, you can build the microcode into the kernel. For that you
1322 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1323 config option.
506f1d07 1324
8d86f390 1325config MICROCODE_INTEL
e43f6e67 1326 bool "Intel microcode loading support"
8f9ca475
IM
1327 depends on MICROCODE
1328 default MICROCODE
a7f7f624 1329 help
8f9ca475
IM
1330 This options enables microcode patch loading support for Intel
1331 processors.
1332
b8989db9
A
1333 For the current Intel microcode data package go to
1334 <https://downloadcenter.intel.com> and search for
1335 'Linux Processor Microcode Data File'.
8d86f390 1336
80cc9f10 1337config MICROCODE_AMD
e43f6e67 1338 bool "AMD microcode loading support"
8f9ca475 1339 depends on MICROCODE
a7f7f624 1340 help
8f9ca475
IM
1341 If you select this option, microcode patch loading support for AMD
1342 processors will be enabled.
80cc9f10 1343
8f9ca475 1344config MICROCODE_OLD_INTERFACE
c02f48e0
BP
1345 bool "Ancient loading interface (DEPRECATED)"
1346 default n
506f1d07 1347 depends on MICROCODE
a7f7f624 1348 help
c02f48e0
BP
1349 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1350 which was used by userspace tools like iucode_tool and microcode.ctl.
1351 It is inadequate because it runs too late to be able to properly
1352 load microcode on a machine and it needs special tools. Instead, you
1353 should've switched to the early loading method with the initrd or
cb1aaebe 1354 builtin microcode by now: Documentation/x86/microcode.rst
506f1d07
SR
1355
1356config X86_MSR
1357 tristate "/dev/cpu/*/msr - Model-specific register support"
a7f7f624 1358 help
506f1d07
SR
1359 This device gives privileged processes access to the x86
1360 Model-Specific Registers (MSRs). It is a character device with
1361 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1362 MSR accesses are directed to a specific CPU on multi-processor
1363 systems.
1364
1365config X86_CPUID
1366 tristate "/dev/cpu/*/cpuid - CPU information support"
a7f7f624 1367 help
506f1d07
SR
1368 This device gives processes access to the x86 CPUID instruction to
1369 be executed on a specific processor. It is a character device
1370 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1371 /dev/cpu/31/cpuid.
1372
1373choice
1374 prompt "High Memory Support"
6fc108a0 1375 default HIGHMEM4G
506f1d07
SR
1376 depends on X86_32
1377
1378config NOHIGHMEM
1379 bool "off"
a7f7f624 1380 help
506f1d07
SR
1381 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1382 However, the address space of 32-bit x86 processors is only 4
1383 Gigabytes large. That means that, if you have a large amount of
1384 physical memory, not all of it can be "permanently mapped" by the
1385 kernel. The physical memory that's not permanently mapped is called
1386 "high memory".
1387
1388 If you are compiling a kernel which will never run on a machine with
1389 more than 1 Gigabyte total physical RAM, answer "off" here (default
1390 choice and suitable for most users). This will result in a "3GB/1GB"
1391 split: 3GB are mapped so that each process sees a 3GB virtual memory
1392 space and the remaining part of the 4GB virtual memory space is used
1393 by the kernel to permanently map as much physical memory as
1394 possible.
1395
1396 If the machine has between 1 and 4 Gigabytes physical RAM, then
1397 answer "4GB" here.
1398
1399 If more than 4 Gigabytes is used then answer "64GB" here. This
1400 selection turns Intel PAE (Physical Address Extension) mode on.
1401 PAE implements 3-level paging on IA32 processors. PAE is fully
1402 supported by Linux, PAE mode is implemented on all recent Intel
1403 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1404 then the kernel will not boot on CPUs that don't support PAE!
1405
1406 The actual amount of total physical memory will either be
1407 auto detected or can be forced by using a kernel command line option
1408 such as "mem=256M". (Try "man bootparam" or see the documentation of
1409 your boot loader (lilo or loadlin) about how to pass options to the
1410 kernel at boot time.)
1411
1412 If unsure, say "off".
1413
1414config HIGHMEM4G
1415 bool "4GB"
a7f7f624 1416 help
506f1d07
SR
1417 Select this if you have a 32-bit processor and between 1 and 4
1418 gigabytes of physical RAM.
1419
1420config HIGHMEM64G
1421 bool "64GB"
225bac2d 1422 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
506f1d07 1423 select X86_PAE
a7f7f624 1424 help
506f1d07
SR
1425 Select this if you have a 32-bit processor and more than 4
1426 gigabytes of physical RAM.
1427
1428endchoice
1429
1430choice
6a108a14 1431 prompt "Memory split" if EXPERT
506f1d07
SR
1432 default VMSPLIT_3G
1433 depends on X86_32
a7f7f624 1434 help
506f1d07
SR
1435 Select the desired split between kernel and user memory.
1436
1437 If the address range available to the kernel is less than the
1438 physical memory installed, the remaining memory will be available
1439 as "high memory". Accessing high memory is a little more costly
1440 than low memory, as it needs to be mapped into the kernel first.
1441 Note that increasing the kernel address space limits the range
1442 available to user programs, making the address space there
1443 tighter. Selecting anything other than the default 3G/1G split
1444 will also likely make your kernel incompatible with binary-only
1445 kernel modules.
1446
1447 If you are not absolutely sure what you are doing, leave this
1448 option alone!
1449
1450 config VMSPLIT_3G
1451 bool "3G/1G user/kernel split"
1452 config VMSPLIT_3G_OPT
1453 depends on !X86_PAE
1454 bool "3G/1G user/kernel split (for full 1G low memory)"
1455 config VMSPLIT_2G
1456 bool "2G/2G user/kernel split"
1457 config VMSPLIT_2G_OPT
1458 depends on !X86_PAE
1459 bool "2G/2G user/kernel split (for full 2G low memory)"
1460 config VMSPLIT_1G
1461 bool "1G/3G user/kernel split"
1462endchoice
1463
1464config PAGE_OFFSET
1465 hex
1466 default 0xB0000000 if VMSPLIT_3G_OPT
1467 default 0x80000000 if VMSPLIT_2G
1468 default 0x78000000 if VMSPLIT_2G_OPT
1469 default 0x40000000 if VMSPLIT_1G
1470 default 0xC0000000
1471 depends on X86_32
1472
1473config HIGHMEM
3c2362e6 1474 def_bool y
506f1d07 1475 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
506f1d07
SR
1476
1477config X86_PAE
9ba16087 1478 bool "PAE (Physical Address Extension) Support"
506f1d07 1479 depends on X86_32 && !HIGHMEM4G
d4a451d5 1480 select PHYS_ADDR_T_64BIT
9d99c712 1481 select SWIOTLB
a7f7f624 1482 help
506f1d07
SR
1483 PAE is required for NX support, and furthermore enables
1484 larger swapspace support for non-overcommit purposes. It
1485 has the cost of more pagetable lookup overhead, and also
1486 consumes more pagetable space per process.
1487
77ef56e4
KS
1488config X86_5LEVEL
1489 bool "Enable 5-level page tables support"
18ec1eaf 1490 default y
eedb92ab 1491 select DYNAMIC_MEMORY_LAYOUT
162434e7 1492 select SPARSEMEM_VMEMMAP
77ef56e4 1493 depends on X86_64
a7f7f624 1494 help
77ef56e4
KS
1495 5-level paging enables access to larger address space:
1496 upto 128 PiB of virtual address space and 4 PiB of
1497 physical address space.
1498
1499 It will be supported by future Intel CPUs.
1500
6657fca0
KS
1501 A kernel with the option enabled can be booted on machines that
1502 support 4- or 5-level paging.
77ef56e4 1503
cb1aaebe 1504 See Documentation/x86/x86_64/5level-paging.rst for more
77ef56e4
KS
1505 information.
1506
1507 Say N if unsure.
1508
10971ab2 1509config X86_DIRECT_GBPAGES
e5008abe 1510 def_bool y
2e1da13f 1511 depends on X86_64
a7f7f624 1512 help
10971ab2
IM
1513 Certain kernel features effectively disable kernel
1514 linear 1 GB mappings (even if the CPU otherwise
1515 supports them), so don't confuse the user by printing
1516 that we have them enabled.
9e899816 1517
5c280cf6
TG
1518config X86_CPA_STATISTICS
1519 bool "Enable statistic for Change Page Attribute"
1520 depends on DEBUG_FS
a7f7f624 1521 help
b75baaf3 1522 Expose statistics about the Change Page Attribute mechanism, which
a943245a 1523 helps to determine the effectiveness of preserving large and huge
5c280cf6
TG
1524 page mappings when mapping protections are changed.
1525
7744ccdb
TL
1526config AMD_MEM_ENCRYPT
1527 bool "AMD Secure Memory Encryption (SME) support"
1528 depends on X86_64 && CPU_SUP_AMD
82fef0ad 1529 select DMA_COHERENT_POOL
94d49eb3 1530 select DYNAMIC_PHYSICAL_MASK
ce9084ba 1531 select ARCH_USE_MEMREMAP_PROT
9087c375 1532 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
597cfe48 1533 select INSTRUCTION_DECODER
22916417 1534 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
aa5a4611 1535 select ARCH_HAS_CC_PLATFORM
a7f7f624 1536 help
7744ccdb
TL
1537 Say yes to enable support for the encryption of system memory.
1538 This requires an AMD processor that supports Secure Memory
1539 Encryption (SME).
1540
1541config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1542 bool "Activate AMD Secure Memory Encryption (SME) by default"
7744ccdb 1543 depends on AMD_MEM_ENCRYPT
a7f7f624 1544 help
7744ccdb
TL
1545 Say yes to have system memory encrypted by default if running on
1546 an AMD processor that supports Secure Memory Encryption (SME).
1547
1548 If set to Y, then the encryption of system memory can be
1549 deactivated with the mem_encrypt=off command line option.
1550
1551 If set to N, then the encryption of system memory can be
1552 activated with the mem_encrypt=on command line option.
1553
506f1d07
SR
1554# Common NUMA Features
1555config NUMA
e133f6ea 1556 bool "NUMA Memory Allocation and Scheduler Support"
506f1d07 1557 depends on SMP
b5660ba7
PA
1558 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1559 default y if X86_BIGSMP
a7f7f624 1560 help
e133f6ea 1561 Enable NUMA (Non-Uniform Memory Access) support.
fd51b2d7 1562
506f1d07
SR
1563 The kernel will try to allocate memory used by a CPU on the
1564 local memory controller of the CPU and add some more
1565 NUMA awareness to the kernel.
1566
c280ea5e 1567 For 64-bit this is recommended if the system is Intel Core i7
fd51b2d7
KM
1568 (or later), AMD Opteron, or EM64T NUMA.
1569
b5660ba7 1570 For 32-bit this is only needed if you boot a 32-bit
7cf6c945 1571 kernel on a 64-bit NUMA platform.
fd51b2d7
KM
1572
1573 Otherwise, you should say N.
506f1d07 1574
eec1d4fa 1575config AMD_NUMA
3c2362e6
HH
1576 def_bool y
1577 prompt "Old style AMD Opteron NUMA detection"
5da0ef9a 1578 depends on X86_64 && NUMA && PCI
a7f7f624 1579 help
eec1d4fa
HR
1580 Enable AMD NUMA node topology detection. You should say Y here if
1581 you have a multi processor AMD system. This uses an old method to
1582 read the NUMA configuration directly from the builtin Northbridge
1583 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1584 which also takes priority if both are compiled in.
506f1d07
SR
1585
1586config X86_64_ACPI_NUMA
3c2362e6
HH
1587 def_bool y
1588 prompt "ACPI NUMA detection"
506f1d07
SR
1589 depends on X86_64 && NUMA && ACPI && PCI
1590 select ACPI_NUMA
a7f7f624 1591 help
506f1d07
SR
1592 Enable ACPI SRAT based node topology detection.
1593
1594config NUMA_EMU
1595 bool "NUMA emulation"
1b7e03ef 1596 depends on NUMA
a7f7f624 1597 help
506f1d07
SR
1598 Enable NUMA emulation. A flat machine will be split
1599 into virtual nodes when booted with "numa=fake=N", where N is the
1600 number of nodes. This is only useful for debugging.
1601
1602config NODES_SHIFT
d25e26b6 1603 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
51591e31
DR
1604 range 1 10
1605 default "10" if MAXSMP
506f1d07 1606 default "6" if X86_64
506f1d07 1607 default "3"
a9ee6cf5 1608 depends on NUMA
a7f7f624 1609 help
1184dc2f 1610 Specify the maximum number of NUMA Nodes available on the target
692105b8 1611 system. Increases memory reserved to accommodate various tables.
506f1d07 1612
506f1d07
SR
1613config ARCH_FLATMEM_ENABLE
1614 def_bool y
3b16651f 1615 depends on X86_32 && !NUMA
506f1d07 1616
506f1d07
SR
1617config ARCH_SPARSEMEM_ENABLE
1618 def_bool y
6ea30386 1619 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
506f1d07
SR
1620 select SPARSEMEM_STATIC if X86_32
1621 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1622
3b16651f 1623config ARCH_SPARSEMEM_DEFAULT
6ad57f7f 1624 def_bool X86_64 || (NUMA && X86_32)
3b16651f 1625
506f1d07
SR
1626config ARCH_SELECT_MEMORY_MODEL
1627 def_bool y
b263295d 1628 depends on ARCH_SPARSEMEM_ENABLE
506f1d07
SR
1629
1630config ARCH_MEMORY_PROBE
a0842b70 1631 bool "Enable sysfs memory/probe interface"
5c11f00b 1632 depends on MEMORY_HOTPLUG
a0842b70
TK
1633 help
1634 This option enables a sysfs memory/probe interface for testing.
cb1aaebe 1635 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
a0842b70 1636 If you are unsure how to answer this question, answer N.
506f1d07 1637
3b16651f
TH
1638config ARCH_PROC_KCORE_TEXT
1639 def_bool y
1640 depends on X86_64 && PROC_KCORE
1641
a29815a3 1642config ILLEGAL_POINTER_VALUE
b03b016f
KK
1643 hex
1644 default 0 if X86_32
1645 default 0xdead000000000000 if X86_64
a29815a3 1646
7a67832c
DW
1647config X86_PMEM_LEGACY_DEVICE
1648 bool
1649
ec776ef6 1650config X86_PMEM_LEGACY
7a67832c 1651 tristate "Support non-standard NVDIMMs and ADR protected memory"
9f53f9fa
DW
1652 depends on PHYS_ADDR_T_64BIT
1653 depends on BLK_DEV
7a67832c 1654 select X86_PMEM_LEGACY_DEVICE
7b27a862 1655 select NUMA_KEEP_MEMINFO if NUMA
9f53f9fa 1656 select LIBNVDIMM
ec776ef6
CH
1657 help
1658 Treat memory marked using the non-standard e820 type of 12 as used
1659 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1660 The kernel will offer these regions to the 'pmem' driver so
1661 they can be used for persistent storage.
1662
1663 Say Y if unsure.
1664
506f1d07
SR
1665config HIGHPTE
1666 bool "Allocate 3rd-level pagetables from highmem"
6fc108a0 1667 depends on HIGHMEM
a7f7f624 1668 help
506f1d07
SR
1669 The VM uses one page table entry for each page of physical memory.
1670 For systems with a lot of RAM, this can be wasteful of precious
1671 low memory. Setting this option will put user-space page table
1672 entries in high memory.
1673
9f077871 1674config X86_CHECK_BIOS_CORRUPTION
8f9ca475 1675 bool "Check for low memory corruption"
a7f7f624 1676 help
8f9ca475
IM
1677 Periodically check for memory corruption in low memory, which
1678 is suspected to be caused by BIOS. Even when enabled in the
1679 configuration, it is disabled at runtime. Enable it by
1680 setting "memory_corruption_check=1" on the kernel command
1681 line. By default it scans the low 64k of memory every 60
1682 seconds; see the memory_corruption_check_size and
1683 memory_corruption_check_period parameters in
8c27ceff 1684 Documentation/admin-guide/kernel-parameters.rst to adjust this.
8f9ca475
IM
1685
1686 When enabled with the default parameters, this option has
1687 almost no overhead, as it reserves a relatively small amount
1688 of memory and scans it infrequently. It both detects corruption
1689 and prevents it from affecting the running system.
1690
1691 It is, however, intended as a diagnostic tool; if repeatable
1692 BIOS-originated corruption always affects the same memory,
1693 you can use memmap= to prevent the kernel from using that
1694 memory.
9f077871 1695
c885df50 1696config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
8f9ca475 1697 bool "Set the default setting of memory_corruption_check"
c885df50
JF
1698 depends on X86_CHECK_BIOS_CORRUPTION
1699 default y
a7f7f624 1700 help
8f9ca475
IM
1701 Set whether the default state of memory_corruption_check is
1702 on or off.
c885df50 1703
506f1d07
SR
1704config MATH_EMULATION
1705 bool
a5b9e5a2 1706 depends on MODIFY_LDT_SYSCALL
87d6021b 1707 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
a7f7f624 1708 help
506f1d07
SR
1709 Linux can emulate a math coprocessor (used for floating point
1710 operations) if you don't have one. 486DX and Pentium processors have
1711 a math coprocessor built in, 486SX and 386 do not, unless you added
1712 a 487DX or 387, respectively. (The messages during boot time can
1713 give you some hints here ["man dmesg"].) Everyone needs either a
1714 coprocessor or this emulation.
1715
1716 If you don't have a math coprocessor, you need to say Y here; if you
1717 say Y here even though you have a coprocessor, the coprocessor will
1718 be used nevertheless. (This behavior can be changed with the kernel
1719 command line option "no387", which comes handy if your coprocessor
1720 is broken. Try "man bootparam" or see the documentation of your boot
1721 loader (lilo or loadlin) about how to pass options to the kernel at
1722 boot time.) This means that it is a good idea to say Y here if you
1723 intend to use this kernel on different machines.
1724
1725 More information about the internals of the Linux math coprocessor
1726 emulation can be found in <file:arch/x86/math-emu/README>.
1727
1728 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1729 kernel, it won't hurt.
1730
1731config MTRR
6fc108a0 1732 def_bool y
6a108a14 1733 prompt "MTRR (Memory Type Range Register) support" if EXPERT
a7f7f624 1734 help
506f1d07
SR
1735 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1736 the Memory Type Range Registers (MTRRs) may be used to control
1737 processor access to memory ranges. This is most useful if you have
1738 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1739 allows bus write transfers to be combined into a larger transfer
1740 before bursting over the PCI/AGP bus. This can increase performance
1741 of image write operations 2.5 times or more. Saying Y here creates a
1742 /proc/mtrr file which may be used to manipulate your processor's
1743 MTRRs. Typically the X server should use this.
1744
1745 This code has a reasonably generic interface so that similar
1746 control registers on other processors can be easily supported
1747 as well:
1748
1749 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1750 Registers (ARRs) which provide a similar functionality to MTRRs. For
1751 these, the ARRs are used to emulate the MTRRs.
1752 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1753 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1754 write-combining. All of these processors are supported by this code
1755 and it makes sense to say Y here if you have one of them.
1756
1757 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1758 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1759 can lead to all sorts of problems, so it's good to say Y here.
1760
1761 You can safely say Y even if your machine doesn't have MTRRs, you'll
1762 just add about 9 KB to your kernel.
1763
cb1aaebe 1764 See <file:Documentation/x86/mtrr.rst> for more information.
506f1d07 1765
95ffa243 1766config MTRR_SANITIZER
2ffb3501 1767 def_bool y
95ffa243
YL
1768 prompt "MTRR cleanup support"
1769 depends on MTRR
a7f7f624 1770 help
aba3728c
TG
1771 Convert MTRR layout from continuous to discrete, so X drivers can
1772 add writeback entries.
95ffa243 1773
aba3728c 1774 Can be disabled with disable_mtrr_cleanup on the kernel command line.
692105b8 1775 The largest mtrr entry size for a continuous block can be set with
aba3728c 1776 mtrr_chunk_size.
95ffa243 1777
2ffb3501 1778 If unsure, say Y.
95ffa243
YL
1779
1780config MTRR_SANITIZER_ENABLE_DEFAULT
f5098d62
YL
1781 int "MTRR cleanup enable value (0-1)"
1782 range 0 1
1783 default "0"
95ffa243 1784 depends on MTRR_SANITIZER
a7f7f624 1785 help
f5098d62 1786 Enable mtrr cleanup default value
95ffa243 1787
12031a62
YL
1788config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1789 int "MTRR cleanup spare reg num (0-7)"
1790 range 0 7
1791 default "1"
1792 depends on MTRR_SANITIZER
a7f7f624 1793 help
12031a62 1794 mtrr cleanup spare entries default, it can be changed via
aba3728c 1795 mtrr_spare_reg_nr=N on the kernel command line.
12031a62 1796
2e5d9c85 1797config X86_PAT
6fc108a0 1798 def_bool y
6a108a14 1799 prompt "x86 PAT support" if EXPERT
2a8a2719 1800 depends on MTRR
a7f7f624 1801 help
2e5d9c85 1802 Use PAT attributes to setup page level cache control.
042b78e4 1803
2e5d9c85 1804 PATs are the modern equivalents of MTRRs and are much more
1805 flexible than MTRRs.
1806
1807 Say N here if you see bootup problems (boot crash, boot hang,
042b78e4 1808 spontaneous reboots) or a non-working video driver.
2e5d9c85 1809
1810 If unsure, say Y.
1811
46cf98cd
VP
1812config ARCH_USES_PG_UNCACHED
1813 def_bool y
1814 depends on X86_PAT
1815
628c6246
PA
1816config ARCH_RANDOM
1817 def_bool y
1818 prompt "x86 architectural random number generator" if EXPERT
a7f7f624 1819 help
628c6246
PA
1820 Enable the x86 architectural RDRAND instruction
1821 (Intel Bull Mountain technology) to generate random numbers.
1822 If supported, this is a high bandwidth, cryptographically
1823 secure hardware random number generator.
1824
51ae4a2d
PA
1825config X86_SMAP
1826 def_bool y
1827 prompt "Supervisor Mode Access Prevention" if EXPERT
a7f7f624 1828 help
51ae4a2d
PA
1829 Supervisor Mode Access Prevention (SMAP) is a security
1830 feature in newer Intel processors. There is a small
1831 performance cost if this enabled and turned on; there is
1832 also a small increase in the kernel size if this is enabled.
1833
1834 If unsure, say Y.
1835
b971880f 1836config X86_UMIP
796ebc81 1837 def_bool y
b971880f 1838 prompt "User Mode Instruction Prevention" if EXPERT
a7f7f624 1839 help
b971880f
BM
1840 User Mode Instruction Prevention (UMIP) is a security feature in
1841 some x86 processors. If enabled, a general protection fault is
1842 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1843 executed in user mode. These instructions unnecessarily expose
1844 information about the hardware state.
796ebc81
RN
1845
1846 The vast majority of applications do not use these instructions.
1847 For the very few that do, software emulation is provided in
1848 specific cases in protected and virtual-8086 modes. Emulated
1849 results are dummy.
aa35f896 1850
35e97790 1851config X86_INTEL_MEMORY_PROTECTION_KEYS
38f3e775 1852 prompt "Memory Protection Keys"
35e97790 1853 def_bool y
284244a9 1854 # Note: only available in 64-bit mode
38f3e775 1855 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
52c8e601
IM
1856 select ARCH_USES_HIGH_VMA_FLAGS
1857 select ARCH_HAS_PKEYS
a7f7f624 1858 help
284244a9
DH
1859 Memory Protection Keys provides a mechanism for enforcing
1860 page-based protections, but without requiring modification of the
1861 page tables when an application changes protection domains.
1862
1eecbcdc 1863 For details, see Documentation/core-api/protection-keys.rst
284244a9
DH
1864
1865 If unsure, say y.
35e97790 1866
db616173
MH
1867choice
1868 prompt "TSX enable mode"
1869 depends on CPU_SUP_INTEL
1870 default X86_INTEL_TSX_MODE_OFF
1871 help
1872 Intel's TSX (Transactional Synchronization Extensions) feature
1873 allows to optimize locking protocols through lock elision which
1874 can lead to a noticeable performance boost.
1875
1876 On the other hand it has been shown that TSX can be exploited
1877 to form side channel attacks (e.g. TAA) and chances are there
1878 will be more of those attacks discovered in the future.
1879
1880 Therefore TSX is not enabled by default (aka tsx=off). An admin
1881 might override this decision by tsx=on the command line parameter.
1882 Even with TSX enabled, the kernel will attempt to enable the best
1883 possible TAA mitigation setting depending on the microcode available
1884 for the particular machine.
1885
1886 This option allows to set the default tsx mode between tsx=on, =off
1887 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1888 details.
1889
1890 Say off if not sure, auto if TSX is in use but it should be used on safe
1891 platforms or on if TSX is in use and the security aspect of tsx is not
1892 relevant.
1893
1894config X86_INTEL_TSX_MODE_OFF
1895 bool "off"
1896 help
1897 TSX is disabled if possible - equals to tsx=off command line parameter.
1898
1899config X86_INTEL_TSX_MODE_ON
1900 bool "on"
1901 help
1902 TSX is always enabled on TSX capable HW - equals the tsx=on command
1903 line parameter.
1904
1905config X86_INTEL_TSX_MODE_AUTO
1906 bool "auto"
1907 help
1908 TSX is enabled on TSX capable HW that is believed to be safe against
1909 side channel attacks- equals the tsx=auto command line parameter.
1910endchoice
1911
e7e05452
SC
1912config X86_SGX
1913 bool "Software Guard eXtensions (SGX)"
1914 depends on X86_64 && CPU_SUP_INTEL
1915 depends on CRYPTO=y
1916 depends on CRYPTO_SHA256=y
1917 select SRCU
1918 select MMU_NOTIFIER
901ddbb9 1919 select NUMA_KEEP_MEMINFO if NUMA
e7e05452
SC
1920 help
1921 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1922 that can be used by applications to set aside private regions of code
1923 and data, referred to as enclaves. An enclave's private memory can
1924 only be accessed by code running within the enclave. Accesses from
1925 outside the enclave, including other enclaves, are disallowed by
1926 hardware.
1927
1928 If unsure, say N.
1929
506f1d07 1930config EFI
9ba16087 1931 bool "EFI runtime service support"
5b83683f 1932 depends on ACPI
f6ce5002 1933 select UCS2_STRING
022ee6c5 1934 select EFI_RUNTIME_WRAPPERS
a7f7f624 1935 help
8f9ca475
IM
1936 This enables the kernel to use EFI runtime services that are
1937 available (such as the EFI variable services).
506f1d07 1938
8f9ca475
IM
1939 This option is only useful on systems that have EFI firmware.
1940 In addition, you should use the latest ELILO loader available
1941 at <http://elilo.sourceforge.net> in order to take advantage
1942 of EFI runtime services. However, even with this option, the
1943 resultant kernel should continue to boot on existing non-EFI
1944 platforms.
506f1d07 1945
291f3632 1946config EFI_STUB
8f24f8c2
AB
1947 bool "EFI stub support"
1948 depends on EFI && !X86_USE_3DNOW
1949 depends on $(cc-option,-mabi=ms) || X86_32
1950 select RELOCATABLE
a7f7f624 1951 help
8f24f8c2 1952 This kernel feature allows a bzImage to be loaded directly
291f3632
MF
1953 by EFI firmware without the use of a bootloader.
1954
4f4cfa6c 1955 See Documentation/admin-guide/efi-stub.rst for more information.
0c759662 1956
7d453eee
MF
1957config EFI_MIXED
1958 bool "EFI mixed-mode support"
1959 depends on EFI_STUB && X86_64
a7f7f624 1960 help
7d453eee
MF
1961 Enabling this feature allows a 64-bit kernel to be booted
1962 on a 32-bit firmware, provided that your CPU supports 64-bit
1963 mode.
1964
1965 Note that it is not possible to boot a mixed-mode enabled
1966 kernel via the EFI boot stub - a bootloader that supports
1967 the EFI handover protocol must be used.
1968
1969 If unsure, say N.
1970
8636a1f9 1971source "kernel/Kconfig.hz"
506f1d07
SR
1972
1973config KEXEC
1974 bool "kexec system call"
2965faa5 1975 select KEXEC_CORE
a7f7f624 1976 help
506f1d07
SR
1977 kexec is a system call that implements the ability to shutdown your
1978 current kernel, and to start another kernel. It is like a reboot
1979 but it is independent of the system firmware. And like a reboot
1980 you can start any kernel with it, not just Linux.
1981
1982 The name comes from the similarity to the exec system call.
1983
1984 It is an ongoing process to be certain the hardware in a machine
1985 is properly shutdown, so do not be surprised if this code does not
bf220695
GU
1986 initially work for you. As of this writing the exact hardware
1987 interface is strongly in flux, so no good recommendation can be
1988 made.
506f1d07 1989
74ca317c
VG
1990config KEXEC_FILE
1991 bool "kexec file based system call"
2965faa5 1992 select KEXEC_CORE
74ca317c 1993 select BUILD_BIN2C
74ca317c
VG
1994 depends on X86_64
1995 depends on CRYPTO=y
1996 depends on CRYPTO_SHA256=y
a7f7f624 1997 help
74ca317c
VG
1998 This is new version of kexec system call. This system call is
1999 file based and takes file descriptors as system call argument
2000 for kernel and initramfs as opposed to list of segments as
2001 accepted by previous system call.
2002
b799a09f
AT
2003config ARCH_HAS_KEXEC_PURGATORY
2004 def_bool KEXEC_FILE
2005
99d5cadf 2006config KEXEC_SIG
8e7d8381 2007 bool "Verify kernel signature during kexec_file_load() syscall"
74ca317c 2008 depends on KEXEC_FILE
a7f7f624 2009 help
d8eb8940 2010
99d5cadf
JB
2011 This option makes the kexec_file_load() syscall check for a valid
2012 signature of the kernel image. The image can still be loaded without
2013 a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2014 there's a signature that we can check, then it must be valid.
2015
2016 In addition to this option, you need to enable signature
d8eb8940
BP
2017 verification for the corresponding kernel image type being
2018 loaded in order for this to work.
8e7d8381 2019
99d5cadf
JB
2020config KEXEC_SIG_FORCE
2021 bool "Require a valid signature in kexec_file_load() syscall"
2022 depends on KEXEC_SIG
a7f7f624 2023 help
99d5cadf
JB
2024 This option makes kernel signature verification mandatory for
2025 the kexec_file_load() syscall.
2026
8e7d8381
VG
2027config KEXEC_BZIMAGE_VERIFY_SIG
2028 bool "Enable bzImage signature verification support"
99d5cadf 2029 depends on KEXEC_SIG
8e7d8381
VG
2030 depends on SIGNED_PE_FILE_VERIFICATION
2031 select SYSTEM_TRUSTED_KEYRING
a7f7f624 2032 help
8e7d8381
VG
2033 Enable bzImage signature verification support.
2034
506f1d07 2035config CRASH_DUMP
04b69447 2036 bool "kernel crash dumps"
506f1d07 2037 depends on X86_64 || (X86_32 && HIGHMEM)
a7f7f624 2038 help
506f1d07
SR
2039 Generate crash dump after being started by kexec.
2040 This should be normally only set in special crash dump kernels
2041 which are loaded in the main kernel with kexec-tools into
2042 a specially reserved region and then later executed after
2043 a crash by kdump/kexec. The crash dump kernel must be compiled
2044 to a memory address not used by the main kernel or BIOS using
2045 PHYSICAL_START, or it must be built as a relocatable image
2046 (CONFIG_RELOCATABLE=y).
330d4810 2047 For more details see Documentation/admin-guide/kdump/kdump.rst
506f1d07 2048
3ab83521 2049config KEXEC_JUMP
6ea30386 2050 bool "kexec jump"
fee7b0d8 2051 depends on KEXEC && HIBERNATION
a7f7f624 2052 help
89081d17
HY
2053 Jump between original kernel and kexeced kernel and invoke
2054 code in physical address mode via KEXEC
3ab83521 2055
506f1d07 2056config PHYSICAL_START
6a108a14 2057 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
ceefccc9 2058 default "0x1000000"
a7f7f624 2059 help
506f1d07
SR
2060 This gives the physical address where the kernel is loaded.
2061
2062 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2063 bzImage will decompress itself to above physical address and
2064 run from there. Otherwise, bzImage will run from the address where
2065 it has been loaded by the boot loader and will ignore above physical
2066 address.
2067
2068 In normal kdump cases one does not have to set/change this option
2069 as now bzImage can be compiled as a completely relocatable image
2070 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2071 address. This option is mainly useful for the folks who don't want
2072 to use a bzImage for capturing the crash dump and want to use a
2073 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2074 to be specifically compiled to run from a specific memory area
2075 (normally a reserved region) and this option comes handy.
2076
ceefccc9
PA
2077 So if you are using bzImage for capturing the crash dump,
2078 leave the value here unchanged to 0x1000000 and set
2079 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2080 for capturing the crash dump change this value to start of
2081 the reserved region. In other words, it can be set based on
2082 the "X" value as specified in the "crashkernel=YM@XM"
2083 command line boot parameter passed to the panic-ed
330d4810 2084 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
ceefccc9 2085 for more details about crash dumps.
506f1d07
SR
2086
2087 Usage of bzImage for capturing the crash dump is recommended as
2088 one does not have to build two kernels. Same kernel can be used
2089 as production kernel and capture kernel. Above option should have
2090 gone away after relocatable bzImage support is introduced. But it
2091 is present because there are users out there who continue to use
2092 vmlinux for dump capture. This option should go away down the
2093 line.
2094
2095 Don't change this unless you know what you are doing.
2096
2097config RELOCATABLE
26717808
PA
2098 bool "Build a relocatable kernel"
2099 default y
a7f7f624 2100 help
506f1d07
SR
2101 This builds a kernel image that retains relocation information
2102 so it can be loaded someplace besides the default 1MB.
2103 The relocations tend to make the kernel binary about 10% larger,
2104 but are discarded at runtime.
2105
2106 One use is for the kexec on panic case where the recovery kernel
2107 must live at a different physical address than the primary
2108 kernel.
2109
2110 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2111 it has been loaded at and the compile time physical address
8ab3820f 2112 (CONFIG_PHYSICAL_START) is used as the minimum location.
506f1d07 2113
8ab3820f 2114config RANDOMIZE_BASE
e8581e3d 2115 bool "Randomize the address of the kernel image (KASLR)"
8ab3820f 2116 depends on RELOCATABLE
6807c846 2117 default y
a7f7f624 2118 help
e8581e3d
BH
2119 In support of Kernel Address Space Layout Randomization (KASLR),
2120 this randomizes the physical address at which the kernel image
2121 is decompressed and the virtual address where the kernel
2122 image is mapped, as a security feature that deters exploit
2123 attempts relying on knowledge of the location of kernel
2124 code internals.
2125
ed9f007e
KC
2126 On 64-bit, the kernel physical and virtual addresses are
2127 randomized separately. The physical address will be anywhere
2128 between 16MB and the top of physical memory (up to 64TB). The
2129 virtual address will be randomized from 16MB up to 1GB (9 bits
2130 of entropy). Note that this also reduces the memory space
2131 available to kernel modules from 1.5GB to 1GB.
2132
2133 On 32-bit, the kernel physical and virtual addresses are
2134 randomized together. They will be randomized from 16MB up to
2135 512MB (8 bits of entropy).
e8581e3d
BH
2136
2137 Entropy is generated using the RDRAND instruction if it is
2138 supported. If RDTSC is supported, its value is mixed into
2139 the entropy pool as well. If neither RDRAND nor RDTSC are
ed9f007e
KC
2140 supported, then entropy is read from the i8254 timer. The
2141 usable entropy is limited by the kernel being built using
2142 2GB addressing, and that PHYSICAL_ALIGN must be at a
2143 minimum of 2MB. As a result, only 10 bits of entropy are
2144 theoretically possible, but the implementations are further
2145 limited due to memory layouts.
e8581e3d 2146
6807c846 2147 If unsure, say Y.
8ab3820f
KC
2148
2149# Relocation on x86 needs some additional build support
845adf72
PA
2150config X86_NEED_RELOCS
2151 def_bool y
8ab3820f 2152 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
845adf72 2153
506f1d07 2154config PHYSICAL_ALIGN
a0215061 2155 hex "Alignment value to which kernel should be aligned"
8ab3820f 2156 default "0x200000"
a0215061
KC
2157 range 0x2000 0x1000000 if X86_32
2158 range 0x200000 0x1000000 if X86_64
a7f7f624 2159 help
506f1d07
SR
2160 This value puts the alignment restrictions on physical address
2161 where kernel is loaded and run from. Kernel is compiled for an
2162 address which meets above alignment restriction.
2163
2164 If bootloader loads the kernel at a non-aligned address and
2165 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2166 address aligned to above value and run from there.
2167
2168 If bootloader loads the kernel at a non-aligned address and
2169 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2170 load address and decompress itself to the address it has been
2171 compiled for and run from there. The address for which kernel is
2172 compiled already meets above alignment restrictions. Hence the
2173 end result is that kernel runs from a physical address meeting
2174 above alignment restrictions.
2175
a0215061
KC
2176 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2177 this value must be a multiple of 0x200000.
2178
506f1d07
SR
2179 Don't change this unless you know what you are doing.
2180
eedb92ab
KS
2181config DYNAMIC_MEMORY_LAYOUT
2182 bool
a7f7f624 2183 help
eedb92ab
KS
2184 This option makes base addresses of vmalloc and vmemmap as well as
2185 __PAGE_OFFSET movable during boot.
2186
0483e1fa
TG
2187config RANDOMIZE_MEMORY
2188 bool "Randomize the kernel memory sections"
2189 depends on X86_64
2190 depends on RANDOMIZE_BASE
eedb92ab 2191 select DYNAMIC_MEMORY_LAYOUT
0483e1fa 2192 default RANDOMIZE_BASE
a7f7f624 2193 help
0483e1fa
TG
2194 Randomizes the base virtual address of kernel memory sections
2195 (physical memory mapping, vmalloc & vmemmap). This security feature
2196 makes exploits relying on predictable memory locations less reliable.
2197
2198 The order of allocations remains unchanged. Entropy is generated in
2199 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2200 configuration have in average 30,000 different possible virtual
2201 addresses for each memory section.
2202
6807c846 2203 If unsure, say Y.
0483e1fa 2204
90397a41
TG
2205config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2206 hex "Physical memory mapping padding" if EXPERT
2207 depends on RANDOMIZE_MEMORY
2208 default "0xa" if MEMORY_HOTPLUG
2209 default "0x0"
2210 range 0x1 0x40 if MEMORY_HOTPLUG
2211 range 0x0 0x40
a7f7f624 2212 help
90397a41
TG
2213 Define the padding in terabytes added to the existing physical
2214 memory size during kernel memory randomization. It is useful
2215 for memory hotplug support but reduces the entropy available for
2216 address randomization.
2217
2218 If unsure, leave at the default value.
2219
506f1d07 2220config HOTPLUG_CPU
bebd024e 2221 def_bool y
40b31360 2222 depends on SMP
506f1d07 2223
80aa1dff
FY
2224config BOOTPARAM_HOTPLUG_CPU0
2225 bool "Set default setting of cpu0_hotpluggable"
2c922cd0 2226 depends on HOTPLUG_CPU
a7f7f624 2227 help
80aa1dff
FY
2228 Set whether default state of cpu0_hotpluggable is on or off.
2229
2230 Say Y here to enable CPU0 hotplug by default. If this switch
2231 is turned on, there is no need to give cpu0_hotplug kernel
2232 parameter and the CPU0 hotplug feature is enabled by default.
2233
2234 Please note: there are two known CPU0 dependencies if you want
2235 to enable the CPU0 hotplug feature either by this switch or by
2236 cpu0_hotplug kernel parameter.
2237
2238 First, resume from hibernate or suspend always starts from CPU0.
2239 So hibernate and suspend are prevented if CPU0 is offline.
2240
2241 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2242 offline if any interrupt can not migrate out of CPU0. There may
2243 be other CPU0 dependencies.
2244
2245 Please make sure the dependencies are under your control before
2246 you enable this feature.
2247
2248 Say N if you don't want to enable CPU0 hotplug feature by default.
2249 You still can enable the CPU0 hotplug feature at boot by kernel
2250 parameter cpu0_hotplug.
2251
a71c8bc5
FY
2252config DEBUG_HOTPLUG_CPU0
2253 def_bool n
2254 prompt "Debug CPU0 hotplug"
2c922cd0 2255 depends on HOTPLUG_CPU
a7f7f624 2256 help
a71c8bc5
FY
2257 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2258 soon as possible and boots up userspace with CPU0 offlined. User
2259 can online CPU0 back after boot time.
2260
2261 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2262 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2263 compilation or giving cpu0_hotplug kernel parameter at boot.
2264
2265 If unsure, say N.
2266
506f1d07 2267config COMPAT_VDSO
b0b49f26
AL
2268 def_bool n
2269 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
953fee1d 2270 depends on COMPAT_32
a7f7f624 2271 help
b0b49f26
AL
2272 Certain buggy versions of glibc will crash if they are
2273 presented with a 32-bit vDSO that is not mapped at the address
2274 indicated in its segment table.
e84446de 2275
b0b49f26
AL
2276 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2277 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2278 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2279 the only released version with the bug, but OpenSUSE 9
2280 contains a buggy "glibc 2.3.2".
506f1d07 2281
b0b49f26
AL
2282 The symptom of the bug is that everything crashes on startup, saying:
2283 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2284
2285 Saying Y here changes the default value of the vdso32 boot
2286 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2287 This works around the glibc bug but hurts performance.
2288
2289 If unsure, say N: if you are compiling your own kernel, you
2290 are unlikely to be using a buggy version of glibc.
506f1d07 2291
3dc33bd3
KC
2292choice
2293 prompt "vsyscall table for legacy applications"
2294 depends on X86_64
625b7b7f 2295 default LEGACY_VSYSCALL_XONLY
3dc33bd3
KC
2296 help
2297 Legacy user code that does not know how to find the vDSO expects
2298 to be able to issue three syscalls by calling fixed addresses in
2299 kernel space. Since this location is not randomized with ASLR,
2300 it can be used to assist security vulnerability exploitation.
2301
2302 This setting can be changed at boot time via the kernel command
bd49e16e 2303 line parameter vsyscall=[emulate|xonly|none].
3dc33bd3
KC
2304
2305 On a system with recent enough glibc (2.14 or newer) and no
2306 static binaries, you can say None without a performance penalty
2307 to improve security.
2308
bd49e16e 2309 If unsure, select "Emulate execution only".
3dc33bd3 2310
3dc33bd3 2311 config LEGACY_VSYSCALL_EMULATE
bd49e16e 2312 bool "Full emulation"
3dc33bd3 2313 help
bd49e16e
AL
2314 The kernel traps and emulates calls into the fixed vsyscall
2315 address mapping. This makes the mapping non-executable, but
2316 it still contains readable known contents, which could be
2317 used in certain rare security vulnerability exploits. This
2318 configuration is recommended when using legacy userspace
2319 that still uses vsyscalls along with legacy binary
2320 instrumentation tools that require code to be readable.
2321
2322 An example of this type of legacy userspace is running
2323 Pin on an old binary that still uses vsyscalls.
2324
2325 config LEGACY_VSYSCALL_XONLY
2326 bool "Emulate execution only"
2327 help
2328 The kernel traps and emulates calls into the fixed vsyscall
2329 address mapping and does not allow reads. This
2330 configuration is recommended when userspace might use the
2331 legacy vsyscall area but support for legacy binary
2332 instrumentation of legacy code is not needed. It mitigates
2333 certain uses of the vsyscall area as an ASLR-bypassing
2334 buffer.
3dc33bd3
KC
2335
2336 config LEGACY_VSYSCALL_NONE
2337 bool "None"
2338 help
2339 There will be no vsyscall mapping at all. This will
2340 eliminate any risk of ASLR bypass due to the vsyscall
2341 fixed address mapping. Attempts to use the vsyscalls
2342 will be reported to dmesg, so that either old or
2343 malicious userspace programs can be identified.
2344
2345endchoice
2346
516cbf37
TB
2347config CMDLINE_BOOL
2348 bool "Built-in kernel command line"
a7f7f624 2349 help
516cbf37
TB
2350 Allow for specifying boot arguments to the kernel at
2351 build time. On some systems (e.g. embedded ones), it is
2352 necessary or convenient to provide some or all of the
2353 kernel boot arguments with the kernel itself (that is,
2354 to not rely on the boot loader to provide them.)
2355
2356 To compile command line arguments into the kernel,
2357 set this option to 'Y', then fill in the
69711ca1 2358 boot arguments in CONFIG_CMDLINE.
516cbf37
TB
2359
2360 Systems with fully functional boot loaders (i.e. non-embedded)
2361 should leave this option set to 'N'.
2362
2363config CMDLINE
2364 string "Built-in kernel command string"
2365 depends on CMDLINE_BOOL
2366 default ""
a7f7f624 2367 help
516cbf37
TB
2368 Enter arguments here that should be compiled into the kernel
2369 image and used at boot time. If the boot loader provides a
2370 command line at boot time, it is appended to this string to
2371 form the full kernel command line, when the system boots.
2372
2373 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2374 change this behavior.
2375
2376 In most cases, the command line (whether built-in or provided
2377 by the boot loader) should specify the device for the root
2378 file system.
2379
2380config CMDLINE_OVERRIDE
2381 bool "Built-in command line overrides boot loader arguments"
645e6466 2382 depends on CMDLINE_BOOL && CMDLINE != ""
a7f7f624 2383 help
516cbf37
TB
2384 Set this option to 'Y' to have the kernel ignore the boot loader
2385 command line, and use ONLY the built-in command line.
2386
2387 This is used to work around broken boot loaders. This should
2388 be set to 'N' under normal conditions.
2389
a5b9e5a2
AL
2390config MODIFY_LDT_SYSCALL
2391 bool "Enable the LDT (local descriptor table)" if EXPERT
2392 default y
a7f7f624 2393 help
a5b9e5a2
AL
2394 Linux can allow user programs to install a per-process x86
2395 Local Descriptor Table (LDT) using the modify_ldt(2) system
2396 call. This is required to run 16-bit or segmented code such as
2397 DOSEMU or some Wine programs. It is also used by some very old
2398 threading libraries.
2399
2400 Enabling this feature adds a small amount of overhead to
2401 context switches and increases the low-level kernel attack
2402 surface. Disabling it removes the modify_ldt(2) system call.
2403
2404 Saying 'N' here may make sense for embedded or server kernels.
2405
3aac3ebe
TG
2406config STRICT_SIGALTSTACK_SIZE
2407 bool "Enforce strict size checking for sigaltstack"
2408 depends on DYNAMIC_SIGFRAME
2409 help
2410 For historical reasons MINSIGSTKSZ is a constant which became
2411 already too small with AVX512 support. Add a mechanism to
2412 enforce strict checking of the sigaltstack size against the
2413 real size of the FPU frame. This option enables the check
2414 by default. It can also be controlled via the kernel command
2415 line option 'strict_sas_size' independent of this config
2416 switch. Enabling it might break existing applications which
2417 allocate a too small sigaltstack but 'work' because they
2418 never get a signal delivered.
2419
2420 Say 'N' unless you want to really enforce this check.
2421
b700e7f0
SJ
2422source "kernel/livepatch/Kconfig"
2423
506f1d07
SR
2424endmenu
2425
3072e413
MH
2426config ARCH_HAS_ADD_PAGES
2427 def_bool y
5c11f00b 2428 depends on ARCH_ENABLE_MEMORY_HOTPLUG
3072e413 2429
f91ef222
OS
2430config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2431 def_bool y
2432
e534c7c5 2433config USE_PERCPU_NUMA_NODE_ID
645a7919 2434 def_bool y
e534c7c5
LS
2435 depends on NUMA
2436
da85f865 2437menu "Power management and ACPI options"
e279b6c1
SR
2438
2439config ARCH_HIBERNATION_HEADER
3c2362e6 2440 def_bool y
44556530 2441 depends on HIBERNATION
e279b6c1
SR
2442
2443source "kernel/power/Kconfig"
2444
2445source "drivers/acpi/Kconfig"
2446
a6b68076 2447config X86_APM_BOOT
6fc108a0 2448 def_bool y
282e5aab 2449 depends on APM
a6b68076 2450
e279b6c1
SR
2451menuconfig APM
2452 tristate "APM (Advanced Power Management) BIOS support"
efefa6f6 2453 depends on X86_32 && PM_SLEEP
a7f7f624 2454 help
e279b6c1
SR
2455 APM is a BIOS specification for saving power using several different
2456 techniques. This is mostly useful for battery powered laptops with
2457 APM compliant BIOSes. If you say Y here, the system time will be
2458 reset after a RESUME operation, the /proc/apm device will provide
2459 battery status information, and user-space programs will receive
2460 notification of APM "events" (e.g. battery status change).
2461
2462 If you select "Y" here, you can disable actual use of the APM
2463 BIOS by passing the "apm=off" option to the kernel at boot time.
2464
2465 Note that the APM support is almost completely disabled for
2466 machines with more than one CPU.
2467
2468 In order to use APM, you will need supporting software. For location
151f4e2b 2469 and more information, read <file:Documentation/power/apm-acpi.rst>
2dc98fd3 2470 and the Battery Powered Linux mini-HOWTO, available from
e279b6c1
SR
2471 <http://www.tldp.org/docs.html#howto>.
2472
2473 This driver does not spin down disk drives (see the hdparm(8)
2474 manpage ("man 8 hdparm") for that), and it doesn't turn off
2475 VESA-compliant "green" monitors.
2476
2477 This driver does not support the TI 4000M TravelMate and the ACER
2478 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2479 desktop machines also don't have compliant BIOSes, and this driver
2480 may cause those machines to panic during the boot phase.
2481
2482 Generally, if you don't have a battery in your machine, there isn't
2483 much point in using this driver and you should say N. If you get
2484 random kernel OOPSes or reboots that don't seem to be related to
2485 anything, try disabling/enabling this option (or disabling/enabling
2486 APM in your BIOS).
2487
2488 Some other things you should try when experiencing seemingly random,
2489 "weird" problems:
2490
2491 1) make sure that you have enough swap space and that it is
2492 enabled.
2493 2) pass the "no-hlt" option to the kernel
2494 3) switch on floating point emulation in the kernel and pass
2495 the "no387" option to the kernel
2496 4) pass the "floppy=nodma" option to the kernel
2497 5) pass the "mem=4M" option to the kernel (thereby disabling
2498 all but the first 4 MB of RAM)
2499 6) make sure that the CPU is not over clocked.
2500 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2501 8) disable the cache from your BIOS settings
2502 9) install a fan for the video card or exchange video RAM
2503 10) install a better fan for the CPU
2504 11) exchange RAM chips
2505 12) exchange the motherboard.
2506
2507 To compile this driver as a module, choose M here: the
2508 module will be called apm.
2509
2510if APM
2511
2512config APM_IGNORE_USER_SUSPEND
2513 bool "Ignore USER SUSPEND"
a7f7f624 2514 help
e279b6c1
SR
2515 This option will ignore USER SUSPEND requests. On machines with a
2516 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2517 series notebooks, it is necessary to say Y because of a BIOS bug.
2518
2519config APM_DO_ENABLE
2520 bool "Enable PM at boot time"
a7f7f624 2521 help
e279b6c1
SR
2522 Enable APM features at boot time. From page 36 of the APM BIOS
2523 specification: "When disabled, the APM BIOS does not automatically
2524 power manage devices, enter the Standby State, enter the Suspend
2525 State, or take power saving steps in response to CPU Idle calls."
2526 This driver will make CPU Idle calls when Linux is idle (unless this
2527 feature is turned off -- see "Do CPU IDLE calls", below). This
2528 should always save battery power, but more complicated APM features
2529 will be dependent on your BIOS implementation. You may need to turn
2530 this option off if your computer hangs at boot time when using APM
2531 support, or if it beeps continuously instead of suspending. Turn
2532 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2533 T400CDT. This is off by default since most machines do fine without
2534 this feature.
2535
2536config APM_CPU_IDLE
dd8af076 2537 depends on CPU_IDLE
e279b6c1 2538 bool "Make CPU Idle calls when idle"
a7f7f624 2539 help
e279b6c1
SR
2540 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2541 On some machines, this can activate improved power savings, such as
2542 a slowed CPU clock rate, when the machine is idle. These idle calls
2543 are made after the idle loop has run for some length of time (e.g.,
2544 333 mS). On some machines, this will cause a hang at boot time or
2545 whenever the CPU becomes idle. (On machines with more than one CPU,
2546 this option does nothing.)
2547
2548config APM_DISPLAY_BLANK
2549 bool "Enable console blanking using APM"
a7f7f624 2550 help
e279b6c1
SR
2551 Enable console blanking using the APM. Some laptops can use this to
2552 turn off the LCD backlight when the screen blanker of the Linux
2553 virtual console blanks the screen. Note that this is only used by
2554 the virtual console screen blanker, and won't turn off the backlight
2555 when using the X Window system. This also doesn't have anything to
2556 do with your VESA-compliant power-saving monitor. Further, this
2557 option doesn't work for all laptops -- it might not turn off your
2558 backlight at all, or it might print a lot of errors to the console,
2559 especially if you are using gpm.
2560
2561config APM_ALLOW_INTS
2562 bool "Allow interrupts during APM BIOS calls"
a7f7f624 2563 help
e279b6c1
SR
2564 Normally we disable external interrupts while we are making calls to
2565 the APM BIOS as a measure to lessen the effects of a badly behaving
2566 BIOS implementation. The BIOS should reenable interrupts if it
2567 needs to. Unfortunately, some BIOSes do not -- especially those in
2568 many of the newer IBM Thinkpads. If you experience hangs when you
2569 suspend, try setting this to Y. Otherwise, say N.
2570
e279b6c1
SR
2571endif # APM
2572
bb0a56ec 2573source "drivers/cpufreq/Kconfig"
e279b6c1
SR
2574
2575source "drivers/cpuidle/Kconfig"
2576
27471fdb
AH
2577source "drivers/idle/Kconfig"
2578
e279b6c1
SR
2579endmenu
2580
2581
2582menu "Bus options (PCI etc.)"
2583
e279b6c1
SR
2584choice
2585 prompt "PCI access mode"
efefa6f6 2586 depends on X86_32 && PCI
e279b6c1 2587 default PCI_GOANY
a7f7f624 2588 help
e279b6c1
SR
2589 On PCI systems, the BIOS can be used to detect the PCI devices and
2590 determine their configuration. However, some old PCI motherboards
2591 have BIOS bugs and may crash if this is done. Also, some embedded
2592 PCI-based systems don't have any BIOS at all. Linux can also try to
2593 detect the PCI hardware directly without using the BIOS.
2594
2595 With this option, you can specify how Linux should detect the
2596 PCI devices. If you choose "BIOS", the BIOS will be used,
2597 if you choose "Direct", the BIOS won't be used, and if you
2598 choose "MMConfig", then PCI Express MMCONFIG will be used.
2599 If you choose "Any", the kernel will try MMCONFIG, then the
2600 direct access method and falls back to the BIOS if that doesn't
2601 work. If unsure, go with the default, which is "Any".
2602
2603config PCI_GOBIOS
2604 bool "BIOS"
2605
2606config PCI_GOMMCONFIG
2607 bool "MMConfig"
2608
2609config PCI_GODIRECT
2610 bool "Direct"
2611
3ef0e1f8 2612config PCI_GOOLPC
76fb6570 2613 bool "OLPC XO-1"
3ef0e1f8
AS
2614 depends on OLPC
2615
2bdd1b03
AS
2616config PCI_GOANY
2617 bool "Any"
2618
e279b6c1
SR
2619endchoice
2620
2621config PCI_BIOS
3c2362e6 2622 def_bool y
efefa6f6 2623 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
e279b6c1
SR
2624
2625# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2626config PCI_DIRECT
3c2362e6 2627 def_bool y
0aba496f 2628 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
e279b6c1
SR
2629
2630config PCI_MMCONFIG
b45c9f36
JK
2631 bool "Support mmconfig PCI config space access" if X86_64
2632 default y
4590d98f 2633 depends on PCI && (ACPI || JAILHOUSE_GUEST)
b45c9f36 2634 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
e279b6c1 2635
3ef0e1f8 2636config PCI_OLPC
2bdd1b03
AS
2637 def_bool y
2638 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
3ef0e1f8 2639
b5401a96
AN
2640config PCI_XEN
2641 def_bool y
2642 depends on PCI && XEN
b5401a96 2643
8364e1f8
JK
2644config MMCONF_FAM10H
2645 def_bool y
2646 depends on X86_64 && PCI_MMCONFIG && ACPI
e279b6c1 2647
3f6ea84a 2648config PCI_CNB20LE_QUIRK
6a108a14 2649 bool "Read CNB20LE Host Bridge Windows" if EXPERT
6ea30386 2650 depends on PCI
3f6ea84a
IS
2651 help
2652 Read the PCI windows out of the CNB20LE host bridge. This allows
2653 PCI hotplug to work on systems with the CNB20LE chipset which do
2654 not have ACPI.
2655
64a5fed6
BH
2656 There's no public spec for this chipset, and this functionality
2657 is known to be incomplete.
2658
2659 You should say N unless you know you need this.
2660
3a495511 2661config ISA_BUS
17a2a129 2662 bool "ISA bus support on modern systems" if EXPERT
3a495511 2663 help
17a2a129
WBG
2664 Expose ISA bus device drivers and options available for selection and
2665 configuration. Enable this option if your target machine has an ISA
2666 bus. ISA is an older system, displaced by PCI and newer bus
2667 architectures -- if your target machine is modern, it probably does
2668 not have an ISA bus.
3a495511
WBG
2669
2670 If unsure, say N.
2671
1c00f016 2672# x86_64 have no ISA slots, but can have ISA-style DMA.
e279b6c1 2673config ISA_DMA_API
1c00f016
DR
2674 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2675 default y
2676 help
2677 Enables ISA-style DMA support for devices requiring such controllers.
2678 If unsure, say Y.
e279b6c1 2679
51e68d05
LT
2680if X86_32
2681
e279b6c1
SR
2682config ISA
2683 bool "ISA support"
a7f7f624 2684 help
e279b6c1
SR
2685 Find out whether you have ISA slots on your motherboard. ISA is the
2686 name of a bus system, i.e. the way the CPU talks to the other stuff
2687 inside your box. Other bus systems are PCI, EISA, MicroChannel
2688 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2689 newer boards don't support it. If you have ISA, say Y, otherwise N.
2690
e279b6c1
SR
2691config SCx200
2692 tristate "NatSemi SCx200 support"
a7f7f624 2693 help
e279b6c1
SR
2694 This provides basic support for National Semiconductor's
2695 (now AMD's) Geode processors. The driver probes for the
2696 PCI-IDs of several on-chip devices, so its a good dependency
2697 for other scx200_* drivers.
2698
2699 If compiled as a module, the driver is named scx200.
2700
2701config SCx200HR_TIMER
2702 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
592913ec 2703 depends on SCx200
e279b6c1 2704 default y
a7f7f624 2705 help
e279b6c1
SR
2706 This driver provides a clocksource built upon the on-chip
2707 27MHz high-resolution timer. Its also a workaround for
2708 NSC Geode SC-1100's buggy TSC, which loses time when the
2709 processor goes idle (as is done by the scheduler). The
2710 other workaround is idle=poll boot option.
2711
3ef0e1f8
AS
2712config OLPC
2713 bool "One Laptop Per Child support"
54008979 2714 depends on !X86_PAE
3c554946 2715 select GPIOLIB
dc3119e7 2716 select OF
45bb1674 2717 select OF_PROMTREE
b4e51854 2718 select IRQ_DOMAIN
0c3d931b 2719 select OLPC_EC
a7f7f624 2720 help
3ef0e1f8
AS
2721 Add support for detecting the unique features of the OLPC
2722 XO hardware.
2723
a3128588
DD
2724config OLPC_XO1_PM
2725 bool "OLPC XO-1 Power Management"
fa112cf1 2726 depends on OLPC && MFD_CS5535=y && PM_SLEEP
a7f7f624 2727 help
97c4cb71 2728 Add support for poweroff and suspend of the OLPC XO-1 laptop.
bf1ebf00 2729
cfee9597
DD
2730config OLPC_XO1_RTC
2731 bool "OLPC XO-1 Real Time Clock"
2732 depends on OLPC_XO1_PM && RTC_DRV_CMOS
a7f7f624 2733 help
cfee9597
DD
2734 Add support for the XO-1 real time clock, which can be used as a
2735 programmable wakeup source.
2736
7feda8e9
DD
2737config OLPC_XO1_SCI
2738 bool "OLPC XO-1 SCI extras"
92e830f2 2739 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
ed8e47fe 2740 depends on INPUT=y
d8d01a63 2741 select POWER_SUPPLY
a7f7f624 2742 help
7feda8e9 2743 Add support for SCI-based features of the OLPC XO-1 laptop:
7bc74b3d 2744 - EC-driven system wakeups
7feda8e9 2745 - Power button
7bc74b3d 2746 - Ebook switch
2cf2baea 2747 - Lid switch
e1040ac6
DD
2748 - AC adapter status updates
2749 - Battery status updates
7feda8e9 2750
a0f30f59
DD
2751config OLPC_XO15_SCI
2752 bool "OLPC XO-1.5 SCI extras"
d8d01a63
DD
2753 depends on OLPC && ACPI
2754 select POWER_SUPPLY
a7f7f624 2755 help
a0f30f59
DD
2756 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2757 - EC-driven system wakeups
2758 - AC adapter status updates
2759 - Battery status updates
bf1ebf00 2760
d4f3e350
EW
2761config ALIX
2762 bool "PCEngines ALIX System Support (LED setup)"
2763 select GPIOLIB
a7f7f624 2764 help
d4f3e350
EW
2765 This option enables system support for the PCEngines ALIX.
2766 At present this just sets up LEDs for GPIO control on
2767 ALIX2/3/6 boards. However, other system specific setup should
2768 get added here.
2769
2770 Note: You must still enable the drivers for GPIO and LED support
2771 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2772
2773 Note: You have to set alix.force=1 for boards with Award BIOS.
2774
da4e3302
PP
2775config NET5501
2776 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2777 select GPIOLIB
a7f7f624 2778 help
da4e3302
PP
2779 This option enables system support for the Soekris Engineering net5501.
2780
3197059a
PP
2781config GEOS
2782 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2783 select GPIOLIB
2784 depends on DMI
a7f7f624 2785 help
3197059a
PP
2786 This option enables system support for the Traverse Technologies GEOS.
2787
7d029125
VD
2788config TS5500
2789 bool "Technologic Systems TS-5500 platform support"
2790 depends on MELAN
2791 select CHECK_SIGNATURE
2792 select NEW_LEDS
2793 select LEDS_CLASS
a7f7f624 2794 help
7d029125
VD
2795 This option enables system support for the Technologic Systems TS-5500.
2796
bc0120fd
SR
2797endif # X86_32
2798
23ac4ae8 2799config AMD_NB
e279b6c1 2800 def_bool y
0e152cd7 2801 depends on CPU_SUP_AMD && PCI
e279b6c1 2802
e279b6c1
SR
2803endmenu
2804
2805
1572497c 2806menu "Binary Emulations"
e279b6c1
SR
2807
2808config IA32_EMULATION
2809 bool "IA32 Emulation"
2810 depends on X86_64
39f88911 2811 select ARCH_WANT_OLD_COMPAT_IPC
d1603990 2812 select BINFMT_ELF
39f88911 2813 select COMPAT_OLD_SIGACTION
a7f7f624 2814 help
5fd92e65
L
2815 Include code to run legacy 32-bit programs under a
2816 64-bit kernel. You should likely turn this on, unless you're
2817 100% sure that you don't have any 32-bit programs left.
e279b6c1
SR
2818
2819config IA32_AOUT
8f9ca475
IM
2820 tristate "IA32 a.out support"
2821 depends on IA32_EMULATION
eac61655 2822 depends on BROKEN
a7f7f624 2823 help
8f9ca475 2824 Support old a.out binaries in the 32bit emulation.
e279b6c1 2825
0bf62763 2826config X86_X32
6ea30386 2827 bool "x32 ABI for 64-bit mode"
9b54050b 2828 depends on X86_64
a7f7f624 2829 help
5fd92e65
L
2830 Include code to run binaries for the x32 native 32-bit ABI
2831 for 64-bit processors. An x32 process gets access to the
2832 full 64-bit register file and wide data path while leaving
2833 pointers at 32 bits for smaller memory footprint.
2834
2835 You will need a recent binutils (2.22 or later) with
2836 elf32_x86_64 support enabled to compile a kernel with this
2837 option set.
2838
953fee1d
IM
2839config COMPAT_32
2840 def_bool y
2841 depends on IA32_EMULATION || X86_32
2842 select HAVE_UID16
2843 select OLD_SIGSUSPEND3
2844
e279b6c1 2845config COMPAT
3c2362e6 2846 def_bool y
0bf62763 2847 depends on IA32_EMULATION || X86_X32
e279b6c1 2848
3120e25e 2849if COMPAT
e279b6c1 2850config COMPAT_FOR_U64_ALIGNMENT
3120e25e 2851 def_bool y
e279b6c1
SR
2852
2853config SYSVIPC_COMPAT
3c2362e6 2854 def_bool y
3120e25e 2855 depends on SYSVIPC
3120e25e 2856endif
ee009e4a 2857
e279b6c1
SR
2858endmenu
2859
2860
e5beae16
KP
2861config HAVE_ATOMIC_IOMAP
2862 def_bool y
2863 depends on X86_32
2864
edf88417 2865source "arch/x86/kvm/Kconfig"
5e8ebd84
JD
2866
2867source "arch/x86/Kconfig.assembler"