1# SPDX-License-Identifier: GPL-2.0 2# Select 32 or 64 bit 3config 64BIT 4 bool "64-bit kernel" if "$(ARCH)" = "x86" 5 default "$(ARCH)" != "i386" 6 help 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 11 def_bool y 12 depends on !64BIT 13 # Options that are inherently 32-bit kernel only: 14 select ARCH_WANT_IPC_PARSE_VERSION 15 select CLKSRC_I8253 16 select CLONE_BACKWARDS 17 select GENERIC_VDSO_32 18 select HAVE_DEBUG_STACKOVERFLOW 19 select KMAP_LOCAL 20 select MODULES_USE_ELF_REL 21 select OLD_SIGACTION 22 select ARCH_SPLIT_ARG64 23 24config X86_64 25 def_bool y 26 depends on 64BIT 27 # Options that are inherently 64-bit kernel only: 28 select ARCH_HAS_GIGANTIC_PAGE 29 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 30 select ARCH_USE_CMPXCHG_LOCKREF 31 select HAVE_ARCH_SOFT_DIRTY 32 select MODULES_USE_ELF_RELA 33 select NEED_DMA_MAP_STATE 34 select SWIOTLB 35 select ARCH_HAS_ELFCORE_COMPAT 36 select ZONE_DMA32 37 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. 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# 55config X86 56 def_bool y 57 # 58 # Note: keep this list sorted alphabetically 59 # 60 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 61 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 62 select ARCH_32BIT_OFF_T if X86_32 63 select ARCH_CLOCKSOURCE_INIT 64 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 65 select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION 66 select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 67 select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG 68 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 69 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 70 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 71 select ARCH_HAS_CACHE_LINE_SIZE 72 select ARCH_HAS_DEBUG_VIRTUAL 73 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 74 select ARCH_HAS_DEVMEM_IS_ALLOWED 75 select ARCH_HAS_EARLY_DEBUG if KGDB 76 select ARCH_HAS_ELF_RANDOMIZE 77 select ARCH_HAS_FAST_MULTIPLIER 78 select ARCH_HAS_FILTER_PGPROT 79 select ARCH_HAS_FORTIFY_SOURCE 80 select ARCH_HAS_GCOV_PROFILE_ALL 81 select ARCH_HAS_KCOV if X86_64 82 select ARCH_HAS_MEM_ENCRYPT 83 select ARCH_HAS_MEMBARRIER_SYNC_CORE 84 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 85 select ARCH_HAS_PMEM_API if X86_64 86 select ARCH_HAS_PTE_DEVMAP if X86_64 87 select ARCH_HAS_PTE_SPECIAL 88 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 89 select ARCH_HAS_COPY_MC if X86_64 90 select ARCH_HAS_SET_MEMORY 91 select ARCH_HAS_SET_DIRECT_MAP 92 select ARCH_HAS_STRICT_KERNEL_RWX 93 select ARCH_HAS_STRICT_MODULE_RWX 94 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 95 select ARCH_HAS_SYSCALL_WRAPPER 96 select ARCH_HAS_UBSAN_SANITIZE_ALL 97 select ARCH_HAS_DEBUG_WX 98 select ARCH_HAS_ZONE_DMA_SET if EXPERT 99 select ARCH_HAVE_NMI_SAFE_CMPXCHG 100 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 101 select ARCH_MIGHT_HAVE_PC_PARPORT 102 select ARCH_MIGHT_HAVE_PC_SERIO 103 select ARCH_STACKWALK 104 select ARCH_SUPPORTS_ACPI 105 select ARCH_SUPPORTS_ATOMIC_RMW 106 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 107 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 108 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 109 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 110 select ARCH_SUPPORTS_LTO_CLANG 111 select ARCH_SUPPORTS_LTO_CLANG_THIN 112 select ARCH_USE_BUILTIN_BSWAP 113 select ARCH_USE_MEMTEST 114 select ARCH_USE_QUEUED_RWLOCKS 115 select ARCH_USE_QUEUED_SPINLOCKS 116 select ARCH_USE_SYM_ANNOTATIONS 117 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 118 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 119 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 120 select ARCH_WANTS_NO_INSTR 121 select ARCH_WANT_HUGE_PMD_SHARE 122 select ARCH_WANT_LD_ORPHAN_WARN 123 select ARCH_WANTS_THP_SWAP if X86_64 124 select ARCH_HAS_PARANOID_L1D_FLUSH 125 select BUILDTIME_TABLE_SORT 126 select CLKEVT_I8253 127 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 128 select CLOCKSOURCE_WATCHDOG 129 select DCACHE_WORD_ACCESS 130 select DYNAMIC_SIGFRAME 131 select EDAC_ATOMIC_SCRUB 132 select EDAC_SUPPORT 133 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 134 select GENERIC_CLOCKEVENTS_MIN_ADJUST 135 select GENERIC_CMOS_UPDATE 136 select GENERIC_CPU_AUTOPROBE 137 select GENERIC_CPU_VULNERABILITIES 138 select GENERIC_EARLY_IOREMAP 139 select GENERIC_ENTRY 140 select GENERIC_IOMAP 141 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 142 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 143 select GENERIC_IRQ_MIGRATION if SMP 144 select GENERIC_IRQ_PROBE 145 select GENERIC_IRQ_RESERVATION_MODE 146 select GENERIC_IRQ_SHOW 147 select GENERIC_PENDING_IRQ if SMP 148 select GENERIC_PTDUMP 149 select GENERIC_SMP_IDLE_THREAD 150 select GENERIC_TIME_VSYSCALL 151 select GENERIC_GETTIMEOFDAY 152 select GENERIC_VDSO_TIME_NS 153 select GUP_GET_PTE_LOW_HIGH if X86_PAE 154 select HARDIRQS_SW_RESEND 155 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 156 select HAVE_ACPI_APEI if ACPI 157 select HAVE_ACPI_APEI_NMI if ACPI 158 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 159 select HAVE_ARCH_AUDITSYSCALL 160 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 161 select HAVE_ARCH_HUGE_VMALLOC if HAVE_ARCH_HUGE_VMAP 162 select HAVE_ARCH_JUMP_LABEL 163 select HAVE_ARCH_JUMP_LABEL_RELATIVE 164 select HAVE_ARCH_KASAN if X86_64 165 select HAVE_ARCH_KASAN_VMALLOC if X86_64 166 select HAVE_ARCH_KFENCE 167 select HAVE_ARCH_KGDB 168 select HAVE_ARCH_MMAP_RND_BITS if MMU 169 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 170 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 171 select HAVE_ARCH_PREL32_RELOCATIONS 172 select HAVE_ARCH_SECCOMP_FILTER 173 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 174 select HAVE_ARCH_STACKLEAK 175 select HAVE_ARCH_TRACEHOOK 176 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 177 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 178 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 179 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 180 select HAVE_ARCH_VMAP_STACK if X86_64 181 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 182 select HAVE_ARCH_WITHIN_STACK_FRAMES 183 select HAVE_ASM_MODVERSIONS 184 select HAVE_CMPXCHG_DOUBLE 185 select HAVE_CMPXCHG_LOCAL 186 select HAVE_CONTEXT_TRACKING if X86_64 187 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING 188 select HAVE_C_RECORDMCOUNT 189 select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION 190 select HAVE_BUILDTIME_MCOUNT_SORT 191 select HAVE_DEBUG_KMEMLEAK 192 select HAVE_DMA_CONTIGUOUS 193 select HAVE_DYNAMIC_FTRACE 194 select HAVE_DYNAMIC_FTRACE_WITH_REGS 195 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 196 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 197 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 198 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 199 select HAVE_EBPF_JIT 200 select HAVE_EFFICIENT_UNALIGNED_ACCESS 201 select HAVE_EISA 202 select HAVE_EXIT_THREAD 203 select HAVE_FAST_GUP 204 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 205 select HAVE_FTRACE_MCOUNT_RECORD 206 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 207 select HAVE_FUNCTION_TRACER 208 select HAVE_GCC_PLUGINS 209 select HAVE_HW_BREAKPOINT 210 select HAVE_IOREMAP_PROT 211 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 212 select HAVE_IRQ_TIME_ACCOUNTING 213 select HAVE_KERNEL_BZIP2 214 select HAVE_KERNEL_GZIP 215 select HAVE_KERNEL_LZ4 216 select HAVE_KERNEL_LZMA 217 select HAVE_KERNEL_LZO 218 select HAVE_KERNEL_XZ 219 select HAVE_KERNEL_ZSTD 220 select HAVE_KPROBES 221 select HAVE_KPROBES_ON_FTRACE 222 select HAVE_FUNCTION_ERROR_INJECTION 223 select HAVE_KRETPROBES 224 select HAVE_KVM 225 select HAVE_LIVEPATCH if X86_64 226 select HAVE_MIXED_BREAKPOINTS_REGS 227 select HAVE_MOD_ARCH_SPECIFIC 228 select HAVE_MOVE_PMD 229 select HAVE_MOVE_PUD 230 select HAVE_NMI 231 select HAVE_OPTPROBES 232 select HAVE_PCSPKR_PLATFORM 233 select HAVE_PERF_EVENTS 234 select HAVE_PERF_EVENTS_NMI 235 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 236 select HAVE_PCI 237 select HAVE_PERF_REGS 238 select HAVE_PERF_USER_STACK_DUMP 239 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 240 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 241 select HAVE_REGS_AND_STACK_ACCESS_API 242 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 243 select HAVE_FUNCTION_ARG_ACCESS_API 244 select HAVE_SETUP_PER_CPU_AREA 245 select HAVE_SOFTIRQ_ON_OWN_STACK 246 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 247 select HAVE_STACK_VALIDATION if X86_64 248 select HAVE_STATIC_CALL 249 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 250 select HAVE_PREEMPT_DYNAMIC 251 select HAVE_RSEQ 252 select HAVE_SYSCALL_TRACEPOINTS 253 select HAVE_UNSTABLE_SCHED_CLOCK 254 select HAVE_USER_RETURN_NOTIFIER 255 select HAVE_GENERIC_VDSO 256 select HOTPLUG_SMT if SMP 257 select IRQ_FORCED_THREADING 258 select NEED_PER_CPU_EMBED_FIRST_CHUNK 259 select NEED_PER_CPU_PAGE_FIRST_CHUNK 260 select NEED_SG_DMA_LENGTH 261 select PCI_DOMAINS if PCI 262 select PCI_LOCKLESS_CONFIG if PCI 263 select PERF_EVENTS 264 select RTC_LIB 265 select RTC_MC146818_LIB 266 select SPARSE_IRQ 267 select SRCU 268 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 269 select SYSCTL_EXCEPTION_TRACE 270 select THREAD_INFO_IN_TASK 271 select TRACE_IRQFLAGS_SUPPORT 272 select USER_STACKTRACE_SUPPORT 273 select VIRT_TO_BUS 274 select HAVE_ARCH_KCSAN if X86_64 275 select X86_FEATURE_NAMES if PROC_FS 276 select PROC_PID_ARCH_STATUS if PROC_FS 277 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 278 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 279 280config INSTRUCTION_DECODER 281 def_bool y 282 depends on KPROBES || PERF_EVENTS || UPROBES 283 284config OUTPUT_FORMAT 285 string 286 default "elf32-i386" if X86_32 287 default "elf64-x86-64" if X86_64 288 289config LOCKDEP_SUPPORT 290 def_bool y 291 292config STACKTRACE_SUPPORT 293 def_bool y 294 295config MMU 296 def_bool y 297 298config ARCH_MMAP_RND_BITS_MIN 299 default 28 if 64BIT 300 default 8 301 302config ARCH_MMAP_RND_BITS_MAX 303 default 32 if 64BIT 304 default 16 305 306config ARCH_MMAP_RND_COMPAT_BITS_MIN 307 default 8 308 309config ARCH_MMAP_RND_COMPAT_BITS_MAX 310 default 16 311 312config SBUS 313 bool 314 315config GENERIC_ISA_DMA 316 def_bool y 317 depends on ISA_DMA_API 318 319config GENERIC_BUG 320 def_bool y 321 depends on BUG 322 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 323 324config GENERIC_BUG_RELATIVE_POINTERS 325 bool 326 327config ARCH_MAY_HAVE_PC_FDC 328 def_bool y 329 depends on ISA_DMA_API 330 331config GENERIC_CALIBRATE_DELAY 332 def_bool y 333 334config ARCH_HAS_CPU_RELAX 335 def_bool y 336 337config ARCH_HAS_FILTER_PGPROT 338 def_bool y 339 340config ARCH_HIBERNATION_POSSIBLE 341 def_bool y 342 343config ARCH_NR_GPIO 344 int 345 default 1024 if X86_64 346 default 512 347 348config ARCH_SUSPEND_POSSIBLE 349 def_bool y 350 351config ARCH_WANT_GENERAL_HUGETLB 352 def_bool y 353 354config AUDIT_ARCH 355 def_bool y if X86_64 356 357config KASAN_SHADOW_OFFSET 358 hex 359 depends on KASAN 360 default 0xdffffc0000000000 361 362config HAVE_INTEL_TXT 363 def_bool y 364 depends on INTEL_IOMMU && ACPI 365 366config X86_32_SMP 367 def_bool y 368 depends on X86_32 && SMP 369 370config X86_64_SMP 371 def_bool y 372 depends on X86_64 && SMP 373 374config ARCH_SUPPORTS_UPROBES 375 def_bool y 376 377config FIX_EARLYCON_MEM 378 def_bool y 379 380config DYNAMIC_PHYSICAL_MASK 381 bool 382 383config PGTABLE_LEVELS 384 int 385 default 5 if X86_5LEVEL 386 default 4 if X86_64 387 default 3 if X86_PAE 388 default 2 389 390config CC_HAS_SANE_STACKPROTECTOR 391 bool 392 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 393 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 394 help 395 We have to make sure stack protector is unconditionally disabled if 396 the compiler produces broken code or if it does not let us control 397 the segment on 32-bit kernels. 398 399menu "Processor type and features" 400 401config SMP 402 bool "Symmetric multi-processing support" 403 help 404 This enables support for systems with more than one CPU. If you have 405 a system with only one CPU, say N. If you have a system with more 406 than one CPU, say Y. 407 408 If you say N here, the kernel will run on uni- and multiprocessor 409 machines, but will use only one CPU of a multiprocessor machine. If 410 you say Y here, the kernel will run on many, but not all, 411 uniprocessor machines. On a uniprocessor machine, the kernel 412 will run faster if you say N here. 413 414 Note that if you say Y here and choose architecture "586" or 415 "Pentium" under "Processor family", the kernel will not work on 486 416 architectures. Similarly, multiprocessor kernels for the "PPro" 417 architecture may not work on all Pentium based boards. 418 419 People using multiprocessor machines who say Y here should also say 420 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 421 Management" code will be disabled if you say Y here. 422 423 See also <file:Documentation/x86/i386/IO-APIC.rst>, 424 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 425 <http://www.tldp.org/docs.html#howto>. 426 427 If you don't know what to do here, say N. 428 429config X86_FEATURE_NAMES 430 bool "Processor feature human-readable names" if EMBEDDED 431 default y 432 help 433 This option compiles in a table of x86 feature bits and corresponding 434 names. This is required to support /proc/cpuinfo and a few kernel 435 messages. You can disable this to save space, at the expense of 436 making those few kernel messages show numeric feature bits instead. 437 438 If in doubt, say Y. 439 440config X86_X2APIC 441 bool "Support x2apic" 442 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 443 help 444 This enables x2apic support on CPUs that have this feature. 445 446 This allows 32-bit apic IDs (so it can support very large systems), 447 and accesses the local apic via MSRs not via mmio. 448 449 If you don't know what to do here, say N. 450 451config X86_MPPARSE 452 bool "Enable MPS table" if ACPI 453 default y 454 depends on X86_LOCAL_APIC 455 help 456 For old smp systems that do not have proper acpi support. Newer systems 457 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 458 459config GOLDFISH 460 def_bool y 461 depends on X86_GOLDFISH 462 463config RETPOLINE 464 bool "Avoid speculative indirect branches in kernel" 465 default y 466 help 467 Compile kernel with the retpoline compiler options to guard against 468 kernel-to-user data leaks by avoiding speculative indirect 469 branches. Requires a compiler with -mindirect-branch=thunk-extern 470 support for full protection. The kernel may run slower. 471 472config CC_HAS_SLS 473 def_bool $(cc-option,-mharden-sls=all) 474 475config SLS 476 bool "Mitigate Straight-Line-Speculation" 477 depends on CC_HAS_SLS && X86_64 478 default n 479 help 480 Compile the kernel with straight-line-speculation options to guard 481 against straight line speculation. The kernel image might be slightly 482 larger. 483 484config X86_CPU_RESCTRL 485 bool "x86 CPU resource control support" 486 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 487 select KERNFS 488 select PROC_CPU_RESCTRL if PROC_FS 489 help 490 Enable x86 CPU resource control support. 491 492 Provide support for the allocation and monitoring of system resources 493 usage by the CPU. 494 495 Intel calls this Intel Resource Director Technology 496 (Intel(R) RDT). More information about RDT can be found in the 497 Intel x86 Architecture Software Developer Manual. 498 499 AMD calls this AMD Platform Quality of Service (AMD QoS). 500 More information about AMD QoS can be found in the AMD64 Technology 501 Platform Quality of Service Extensions manual. 502 503 Say N if unsure. 504 505if X86_32 506config X86_BIGSMP 507 bool "Support for big SMP systems with more than 8 CPUs" 508 depends on SMP 509 help 510 This option is needed for the systems that have more than 8 CPUs. 511 512config X86_EXTENDED_PLATFORM 513 bool "Support for extended (non-PC) x86 platforms" 514 default y 515 help 516 If you disable this option then the kernel will only support 517 standard PC platforms. (which covers the vast majority of 518 systems out there.) 519 520 If you enable this option then you'll be able to select support 521 for the following (non-PC) 32 bit x86 platforms: 522 Goldfish (Android emulator) 523 AMD Elan 524 RDC R-321x SoC 525 SGI 320/540 (Visual Workstation) 526 STA2X11-based (e.g. Northville) 527 Moorestown MID devices 528 529 If you have one of these systems, or if you want to build a 530 generic distribution kernel, say Y here - otherwise say N. 531endif 532 533if X86_64 534config X86_EXTENDED_PLATFORM 535 bool "Support for extended (non-PC) x86 platforms" 536 default y 537 help 538 If you disable this option then the kernel will only support 539 standard PC platforms. (which covers the vast majority of 540 systems out there.) 541 542 If you enable this option then you'll be able to select support 543 for the following (non-PC) 64 bit x86 platforms: 544 Numascale NumaChip 545 ScaleMP vSMP 546 SGI Ultraviolet 547 548 If you have one of these systems, or if you want to build a 549 generic distribution kernel, say Y here - otherwise say N. 550endif 551# This is an alphabetically sorted list of 64 bit extended platforms 552# Please maintain the alphabetic order if and when there are additions 553config X86_NUMACHIP 554 bool "Numascale NumaChip" 555 depends on X86_64 556 depends on X86_EXTENDED_PLATFORM 557 depends on NUMA 558 depends on SMP 559 depends on X86_X2APIC 560 depends on PCI_MMCONFIG 561 help 562 Adds support for Numascale NumaChip large-SMP systems. Needed to 563 enable more than ~168 cores. 564 If you don't have one of these, you should say N here. 565 566config X86_VSMP 567 bool "ScaleMP vSMP" 568 select HYPERVISOR_GUEST 569 select PARAVIRT 570 depends on X86_64 && PCI 571 depends on X86_EXTENDED_PLATFORM 572 depends on SMP 573 help 574 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 575 supposed to run on these EM64T-based machines. Only choose this option 576 if you have one of these machines. 577 578config X86_UV 579 bool "SGI Ultraviolet" 580 depends on X86_64 581 depends on X86_EXTENDED_PLATFORM 582 depends on NUMA 583 depends on EFI 584 depends on KEXEC_CORE 585 depends on X86_X2APIC 586 depends on PCI 587 help 588 This option is needed in order to support SGI Ultraviolet systems. 589 If you don't have one of these, you should say N here. 590 591# Following is an alphabetically sorted list of 32 bit extended platforms 592# Please maintain the alphabetic order if and when there are additions 593 594config X86_GOLDFISH 595 bool "Goldfish (Virtual Platform)" 596 depends on X86_EXTENDED_PLATFORM 597 help 598 Enable support for the Goldfish virtual platform used primarily 599 for Android development. Unless you are building for the Android 600 Goldfish emulator say N here. 601 602config X86_INTEL_CE 603 bool "CE4100 TV platform" 604 depends on PCI 605 depends on PCI_GODIRECT 606 depends on X86_IO_APIC 607 depends on X86_32 608 depends on X86_EXTENDED_PLATFORM 609 select X86_REBOOTFIXUPS 610 select OF 611 select OF_EARLY_FLATTREE 612 help 613 Select for the Intel CE media processor (CE4100) SOC. 614 This option compiles in support for the CE4100 SOC for settop 615 boxes and media devices. 616 617config X86_INTEL_MID 618 bool "Intel MID platform support" 619 depends on X86_EXTENDED_PLATFORM 620 depends on X86_PLATFORM_DEVICES 621 depends on PCI 622 depends on X86_64 || (PCI_GOANY && X86_32) 623 depends on X86_IO_APIC 624 select I2C 625 select DW_APB_TIMER 626 select INTEL_SCU_PCI 627 help 628 Select to build a kernel capable of supporting Intel MID (Mobile 629 Internet Device) platform systems which do not have the PCI legacy 630 interfaces. If you are building for a PC class system say N here. 631 632 Intel MID platforms are based on an Intel processor and chipset which 633 consume less power than most of the x86 derivatives. 634 635config X86_INTEL_QUARK 636 bool "Intel Quark platform support" 637 depends on X86_32 638 depends on X86_EXTENDED_PLATFORM 639 depends on X86_PLATFORM_DEVICES 640 depends on X86_TSC 641 depends on PCI 642 depends on PCI_GOANY 643 depends on X86_IO_APIC 644 select IOSF_MBI 645 select INTEL_IMR 646 select COMMON_CLK 647 help 648 Select to include support for Quark X1000 SoC. 649 Say Y here if you have a Quark based system such as the Arduino 650 compatible Intel Galileo. 651 652config X86_INTEL_LPSS 653 bool "Intel Low Power Subsystem Support" 654 depends on X86 && ACPI && PCI 655 select COMMON_CLK 656 select PINCTRL 657 select IOSF_MBI 658 help 659 Select to build support for Intel Low Power Subsystem such as 660 found on Intel Lynxpoint PCH. Selecting this option enables 661 things like clock tree (common clock framework) and pincontrol 662 which are needed by the LPSS peripheral drivers. 663 664config X86_AMD_PLATFORM_DEVICE 665 bool "AMD ACPI2Platform devices support" 666 depends on ACPI 667 select COMMON_CLK 668 select PINCTRL 669 help 670 Select to interpret AMD specific ACPI device to platform device 671 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 672 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 673 implemented under PINCTRL subsystem. 674 675config IOSF_MBI 676 tristate "Intel SoC IOSF Sideband support for SoC platforms" 677 depends on PCI 678 help 679 This option enables sideband register access support for Intel SoC 680 platforms. On these platforms the IOSF sideband is used in lieu of 681 MSR's for some register accesses, mostly but not limited to thermal 682 and power. Drivers may query the availability of this device to 683 determine if they need the sideband in order to work on these 684 platforms. The sideband is available on the following SoC products. 685 This list is not meant to be exclusive. 686 - BayTrail 687 - Braswell 688 - Quark 689 690 You should say Y if you are running a kernel on one of these SoC's. 691 692config IOSF_MBI_DEBUG 693 bool "Enable IOSF sideband access through debugfs" 694 depends on IOSF_MBI && DEBUG_FS 695 help 696 Select this option to expose the IOSF sideband access registers (MCR, 697 MDR, MCRX) through debugfs to write and read register information from 698 different units on the SoC. This is most useful for obtaining device 699 state information for debug and analysis. As this is a general access 700 mechanism, users of this option would have specific knowledge of the 701 device they want to access. 702 703 If you don't require the option or are in doubt, say N. 704 705config X86_RDC321X 706 bool "RDC R-321x SoC" 707 depends on X86_32 708 depends on X86_EXTENDED_PLATFORM 709 select M486 710 select X86_REBOOTFIXUPS 711 help 712 This option is needed for RDC R-321x system-on-chip, also known 713 as R-8610-(G). 714 If you don't have one of these chips, you should say N here. 715 716config X86_32_NON_STANDARD 717 bool "Support non-standard 32-bit SMP architectures" 718 depends on X86_32 && SMP 719 depends on X86_EXTENDED_PLATFORM 720 help 721 This option compiles in the bigsmp and STA2X11 default 722 subarchitectures. It is intended for a generic binary 723 kernel. If you select them all, kernel will probe it one by 724 one and will fallback to default. 725 726# Alphabetically sorted list of Non standard 32 bit platforms 727 728config X86_SUPPORTS_MEMORY_FAILURE 729 def_bool y 730 # MCE code calls memory_failure(): 731 depends on X86_MCE 732 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 733 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 734 depends on X86_64 || !SPARSEMEM 735 select ARCH_SUPPORTS_MEMORY_FAILURE 736 737config STA2X11 738 bool "STA2X11 Companion Chip Support" 739 depends on X86_32_NON_STANDARD && PCI 740 select SWIOTLB 741 select MFD_STA2X11 742 select GPIOLIB 743 help 744 This adds support for boards based on the STA2X11 IO-Hub, 745 a.k.a. "ConneXt". The chip is used in place of the standard 746 PC chipset, so all "standard" peripherals are missing. If this 747 option is selected the kernel will still be able to boot on 748 standard PC machines. 749 750config X86_32_IRIS 751 tristate "Eurobraille/Iris poweroff module" 752 depends on X86_32 753 help 754 The Iris machines from EuroBraille do not have APM or ACPI support 755 to shut themselves down properly. A special I/O sequence is 756 needed to do so, which is what this module does at 757 kernel shutdown. 758 759 This is only for Iris machines from EuroBraille. 760 761 If unused, say N. 762 763config SCHED_OMIT_FRAME_POINTER 764 def_bool y 765 prompt "Single-depth WCHAN output" 766 depends on X86 767 help 768 Calculate simpler /proc/<PID>/wchan values. If this option 769 is disabled then wchan values will recurse back to the 770 caller function. This provides more accurate wchan values, 771 at the expense of slightly more scheduling overhead. 772 773 If in doubt, say "Y". 774 775menuconfig HYPERVISOR_GUEST 776 bool "Linux guest support" 777 help 778 Say Y here to enable options for running Linux under various hyper- 779 visors. This option enables basic hypervisor detection and platform 780 setup. 781 782 If you say N, all options in this submenu will be skipped and 783 disabled, and Linux guest support won't be built in. 784 785if HYPERVISOR_GUEST 786 787config PARAVIRT 788 bool "Enable paravirtualization code" 789 depends on HAVE_STATIC_CALL 790 help 791 This changes the kernel so it can modify itself when it is run 792 under a hypervisor, potentially improving performance significantly 793 over full virtualization. However, when run without a hypervisor 794 the kernel is theoretically slower and slightly larger. 795 796config PARAVIRT_XXL 797 bool 798 799config PARAVIRT_DEBUG 800 bool "paravirt-ops debugging" 801 depends on PARAVIRT && DEBUG_KERNEL 802 help 803 Enable to debug paravirt_ops internals. Specifically, BUG if 804 a paravirt_op is missing when it is called. 805 806config PARAVIRT_SPINLOCKS 807 bool "Paravirtualization layer for spinlocks" 808 depends on PARAVIRT && SMP 809 help 810 Paravirtualized spinlocks allow a pvops backend to replace the 811 spinlock implementation with something virtualization-friendly 812 (for example, block the virtual CPU rather than spinning). 813 814 It has a minimal impact on native kernels and gives a nice performance 815 benefit on paravirtualized KVM / Xen kernels. 816 817 If you are unsure how to answer this question, answer Y. 818 819config X86_HV_CALLBACK_VECTOR 820 def_bool n 821 822source "arch/x86/xen/Kconfig" 823 824config KVM_GUEST 825 bool "KVM Guest support (including kvmclock)" 826 depends on PARAVIRT 827 select PARAVIRT_CLOCK 828 select ARCH_CPUIDLE_HALTPOLL 829 select X86_HV_CALLBACK_VECTOR 830 default y 831 help 832 This option enables various optimizations for running under the KVM 833 hypervisor. It includes a paravirtualized clock, so that instead 834 of relying on a PIT (or probably other) emulation by the 835 underlying device model, the host provides the guest with 836 timing infrastructure such as time of day, and system time 837 838config ARCH_CPUIDLE_HALTPOLL 839 def_bool n 840 prompt "Disable host haltpoll when loading haltpoll driver" 841 help 842 If virtualized under KVM, disable host haltpoll. 843 844config PVH 845 bool "Support for running PVH guests" 846 help 847 This option enables the PVH entry point for guest virtual machines 848 as specified in the x86/HVM direct boot ABI. 849 850config PARAVIRT_TIME_ACCOUNTING 851 bool "Paravirtual steal time accounting" 852 depends on PARAVIRT 853 help 854 Select this option to enable fine granularity task steal time 855 accounting. Time spent executing other tasks in parallel with 856 the current vCPU is discounted from the vCPU power. To account for 857 that, there can be a small performance impact. 858 859 If in doubt, say N here. 860 861config PARAVIRT_CLOCK 862 bool 863 864config JAILHOUSE_GUEST 865 bool "Jailhouse non-root cell support" 866 depends on X86_64 && PCI 867 select X86_PM_TIMER 868 help 869 This option allows to run Linux as guest in a Jailhouse non-root 870 cell. You can leave this option disabled if you only want to start 871 Jailhouse and run Linux afterwards in the root cell. 872 873config ACRN_GUEST 874 bool "ACRN Guest support" 875 depends on X86_64 876 select X86_HV_CALLBACK_VECTOR 877 help 878 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 879 a flexible, lightweight reference open-source hypervisor, built with 880 real-time and safety-criticality in mind. It is built for embedded 881 IOT with small footprint and real-time features. More details can be 882 found in https://projectacrn.org/. 883 884endif #HYPERVISOR_GUEST 885 886source "arch/x86/Kconfig.cpu" 887 888config HPET_TIMER 889 def_bool X86_64 890 prompt "HPET Timer Support" if X86_32 891 help 892 Use the IA-PC HPET (High Precision Event Timer) to manage 893 time in preference to the PIT and RTC, if a HPET is 894 present. 895 HPET is the next generation timer replacing legacy 8254s. 896 The HPET provides a stable time base on SMP 897 systems, unlike the TSC, but it is more expensive to access, 898 as it is off-chip. The interface used is documented 899 in the HPET spec, revision 1. 900 901 You can safely choose Y here. However, HPET will only be 902 activated if the platform and the BIOS support this feature. 903 Otherwise the 8254 will be used for timing services. 904 905 Choose N to continue using the legacy 8254 timer. 906 907config HPET_EMULATE_RTC 908 def_bool y 909 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 910 911# Mark as expert because too many people got it wrong. 912# The code disables itself when not needed. 913config DMI 914 default y 915 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 916 bool "Enable DMI scanning" if EXPERT 917 help 918 Enabled scanning of DMI to identify machine quirks. Say Y 919 here unless you have verified that your setup is not 920 affected by entries in the DMI blacklist. Required by PNP 921 BIOS code. 922 923config GART_IOMMU 924 bool "Old AMD GART IOMMU support" 925 select DMA_OPS 926 select IOMMU_HELPER 927 select SWIOTLB 928 depends on X86_64 && PCI && AMD_NB 929 help 930 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 931 GART based hardware IOMMUs. 932 933 The GART supports full DMA access for devices with 32-bit access 934 limitations, on systems with more than 3 GB. This is usually needed 935 for USB, sound, many IDE/SATA chipsets and some other devices. 936 937 Newer systems typically have a modern AMD IOMMU, supported via 938 the CONFIG_AMD_IOMMU=y config option. 939 940 In normal configurations this driver is only active when needed: 941 there's more than 3 GB of memory and the system contains a 942 32-bit limited device. 943 944 If unsure, say Y. 945 946config MAXSMP 947 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 948 depends on X86_64 && SMP && DEBUG_KERNEL 949 select CPUMASK_OFFSTACK 950 help 951 Enable maximum number of CPUS and NUMA Nodes for this architecture. 952 If unsure, say N. 953 954# 955# The maximum number of CPUs supported: 956# 957# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 958# and which can be configured interactively in the 959# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 960# 961# The ranges are different on 32-bit and 64-bit kernels, depending on 962# hardware capabilities and scalability features of the kernel. 963# 964# ( If MAXSMP is enabled we just use the highest possible value and disable 965# interactive configuration. ) 966# 967 968config NR_CPUS_RANGE_BEGIN 969 int 970 default NR_CPUS_RANGE_END if MAXSMP 971 default 1 if !SMP 972 default 2 973 974config NR_CPUS_RANGE_END 975 int 976 depends on X86_32 977 default 64 if SMP && X86_BIGSMP 978 default 8 if SMP && !X86_BIGSMP 979 default 1 if !SMP 980 981config NR_CPUS_RANGE_END 982 int 983 depends on X86_64 984 default 8192 if SMP && CPUMASK_OFFSTACK 985 default 512 if SMP && !CPUMASK_OFFSTACK 986 default 1 if !SMP 987 988config NR_CPUS_DEFAULT 989 int 990 depends on X86_32 991 default 32 if X86_BIGSMP 992 default 8 if SMP 993 default 1 if !SMP 994 995config NR_CPUS_DEFAULT 996 int 997 depends on X86_64 998 default 8192 if MAXSMP 999 default 64 if SMP 1000 default 1 if !SMP 1001 1002config NR_CPUS 1003 int "Maximum number of CPUs" if SMP && !MAXSMP 1004 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1005 default NR_CPUS_DEFAULT 1006 help 1007 This allows you to specify the maximum number of CPUs which this 1008 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1009 supported value is 8192, otherwise the maximum value is 512. The 1010 minimum value which makes sense is 2. 1011 1012 This is purely to save memory: each supported CPU adds about 8KB 1013 to the kernel image. 1014 1015config SCHED_CLUSTER 1016 bool "Cluster scheduler support" 1017 depends on SMP 1018 default y 1019 help 1020 Cluster scheduler support improves the CPU scheduler's decision 1021 making when dealing with machines that have clusters of CPUs. 1022 Cluster usually means a couple of CPUs which are placed closely 1023 by sharing mid-level caches, last-level cache tags or internal 1024 busses. 1025 1026config SCHED_SMT 1027 def_bool y if SMP 1028 1029config SCHED_MC 1030 def_bool y 1031 prompt "Multi-core scheduler support" 1032 depends on SMP 1033 help 1034 Multi-core scheduler support improves the CPU scheduler's decision 1035 making when dealing with multi-core CPU chips at a cost of slightly 1036 increased overhead in some places. If unsure say N here. 1037 1038config SCHED_MC_PRIO 1039 bool "CPU core priorities scheduler support" 1040 depends on SCHED_MC && CPU_SUP_INTEL 1041 select X86_INTEL_PSTATE 1042 select CPU_FREQ 1043 default y 1044 help 1045 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1046 core ordering determined at manufacturing time, which allows 1047 certain cores to reach higher turbo frequencies (when running 1048 single threaded workloads) than others. 1049 1050 Enabling this kernel feature teaches the scheduler about 1051 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1052 scheduler's CPU selection logic accordingly, so that higher 1053 overall system performance can be achieved. 1054 1055 This feature will have no effect on CPUs without this feature. 1056 1057 If unsure say Y here. 1058 1059config UP_LATE_INIT 1060 def_bool y 1061 depends on !SMP && X86_LOCAL_APIC 1062 1063config X86_UP_APIC 1064 bool "Local APIC support on uniprocessors" if !PCI_MSI 1065 default PCI_MSI 1066 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1067 help 1068 A local APIC (Advanced Programmable Interrupt Controller) is an 1069 integrated interrupt controller in the CPU. If you have a single-CPU 1070 system which has a processor with a local APIC, you can say Y here to 1071 enable and use it. If you say Y here even though your machine doesn't 1072 have a local APIC, then the kernel will still run with no slowdown at 1073 all. The local APIC supports CPU-generated self-interrupts (timer, 1074 performance counters), and the NMI watchdog which detects hard 1075 lockups. 1076 1077config X86_UP_IOAPIC 1078 bool "IO-APIC support on uniprocessors" 1079 depends on X86_UP_APIC 1080 help 1081 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1082 SMP-capable replacement for PC-style interrupt controllers. Most 1083 SMP systems and many recent uniprocessor systems have one. 1084 1085 If you have a single-CPU system with an IO-APIC, you can say Y here 1086 to use it. If you say Y here even though your machine doesn't have 1087 an IO-APIC, then the kernel will still run with no slowdown at all. 1088 1089config X86_LOCAL_APIC 1090 def_bool y 1091 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1092 select IRQ_DOMAIN_HIERARCHY 1093 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1094 1095config X86_IO_APIC 1096 def_bool y 1097 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1098 1099config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1100 bool "Reroute for broken boot IRQs" 1101 depends on X86_IO_APIC 1102 help 1103 This option enables a workaround that fixes a source of 1104 spurious interrupts. This is recommended when threaded 1105 interrupt handling is used on systems where the generation of 1106 superfluous "boot interrupts" cannot be disabled. 1107 1108 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1109 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1110 kernel does during interrupt handling). On chipsets where this 1111 boot IRQ generation cannot be disabled, this workaround keeps 1112 the original IRQ line masked so that only the equivalent "boot 1113 IRQ" is delivered to the CPUs. The workaround also tells the 1114 kernel to set up the IRQ handler on the boot IRQ line. In this 1115 way only one interrupt is delivered to the kernel. Otherwise 1116 the spurious second interrupt may cause the kernel to bring 1117 down (vital) interrupt lines. 1118 1119 Only affects "broken" chipsets. Interrupt sharing may be 1120 increased on these systems. 1121 1122config X86_MCE 1123 bool "Machine Check / overheating reporting" 1124 select GENERIC_ALLOCATOR 1125 default y 1126 help 1127 Machine Check support allows the processor to notify the 1128 kernel if it detects a problem (e.g. overheating, data corruption). 1129 The action the kernel takes depends on the severity of the problem, 1130 ranging from warning messages to halting the machine. 1131 1132config X86_MCELOG_LEGACY 1133 bool "Support for deprecated /dev/mcelog character device" 1134 depends on X86_MCE 1135 help 1136 Enable support for /dev/mcelog which is needed by the old mcelog 1137 userspace logging daemon. Consider switching to the new generation 1138 rasdaemon solution. 1139 1140config X86_MCE_INTEL 1141 def_bool y 1142 prompt "Intel MCE features" 1143 depends on X86_MCE && X86_LOCAL_APIC 1144 help 1145 Additional support for intel specific MCE features such as 1146 the thermal monitor. 1147 1148config X86_MCE_AMD 1149 def_bool y 1150 prompt "AMD MCE features" 1151 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1152 help 1153 Additional support for AMD specific MCE features such as 1154 the DRAM Error Threshold. 1155 1156config X86_ANCIENT_MCE 1157 bool "Support for old Pentium 5 / WinChip machine checks" 1158 depends on X86_32 && X86_MCE 1159 help 1160 Include support for machine check handling on old Pentium 5 or WinChip 1161 systems. These typically need to be enabled explicitly on the command 1162 line. 1163 1164config X86_MCE_THRESHOLD 1165 depends on X86_MCE_AMD || X86_MCE_INTEL 1166 def_bool y 1167 1168config X86_MCE_INJECT 1169 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1170 tristate "Machine check injector support" 1171 help 1172 Provide support for injecting machine checks for testing purposes. 1173 If you don't know what a machine check is and you don't do kernel 1174 QA it is safe to say n. 1175 1176source "arch/x86/events/Kconfig" 1177 1178config X86_LEGACY_VM86 1179 bool "Legacy VM86 support" 1180 depends on X86_32 1181 help 1182 This option allows user programs to put the CPU into V8086 1183 mode, which is an 80286-era approximation of 16-bit real mode. 1184 1185 Some very old versions of X and/or vbetool require this option 1186 for user mode setting. Similarly, DOSEMU will use it if 1187 available to accelerate real mode DOS programs. However, any 1188 recent version of DOSEMU, X, or vbetool should be fully 1189 functional even without kernel VM86 support, as they will all 1190 fall back to software emulation. Nevertheless, if you are using 1191 a 16-bit DOS program where 16-bit performance matters, vm86 1192 mode might be faster than emulation and you might want to 1193 enable this option. 1194 1195 Note that any app that works on a 64-bit kernel is unlikely to 1196 need this option, as 64-bit kernels don't, and can't, support 1197 V8086 mode. This option is also unrelated to 16-bit protected 1198 mode and is not needed to run most 16-bit programs under Wine. 1199 1200 Enabling this option increases the complexity of the kernel 1201 and slows down exception handling a tiny bit. 1202 1203 If unsure, say N here. 1204 1205config VM86 1206 bool 1207 default X86_LEGACY_VM86 1208 1209config X86_16BIT 1210 bool "Enable support for 16-bit segments" if EXPERT 1211 default y 1212 depends on MODIFY_LDT_SYSCALL 1213 help 1214 This option is required by programs like Wine to run 16-bit 1215 protected mode legacy code on x86 processors. Disabling 1216 this option saves about 300 bytes on i386, or around 6K text 1217 plus 16K runtime memory on x86-64, 1218 1219config X86_ESPFIX32 1220 def_bool y 1221 depends on X86_16BIT && X86_32 1222 1223config X86_ESPFIX64 1224 def_bool y 1225 depends on X86_16BIT && X86_64 1226 1227config X86_VSYSCALL_EMULATION 1228 bool "Enable vsyscall emulation" if EXPERT 1229 default y 1230 depends on X86_64 1231 help 1232 This enables emulation of the legacy vsyscall page. Disabling 1233 it is roughly equivalent to booting with vsyscall=none, except 1234 that it will also disable the helpful warning if a program 1235 tries to use a vsyscall. With this option set to N, offending 1236 programs will just segfault, citing addresses of the form 1237 0xffffffffff600?00. 1238 1239 This option is required by many programs built before 2013, and 1240 care should be used even with newer programs if set to N. 1241 1242 Disabling this option saves about 7K of kernel size and 1243 possibly 4K of additional runtime pagetable memory. 1244 1245config X86_IOPL_IOPERM 1246 bool "IOPERM and IOPL Emulation" 1247 default y 1248 help 1249 This enables the ioperm() and iopl() syscalls which are necessary 1250 for legacy applications. 1251 1252 Legacy IOPL support is an overbroad mechanism which allows user 1253 space aside of accessing all 65536 I/O ports also to disable 1254 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1255 capabilities and permission from potentially active security 1256 modules. 1257 1258 The emulation restricts the functionality of the syscall to 1259 only allowing the full range I/O port access, but prevents the 1260 ability to disable interrupts from user space which would be 1261 granted if the hardware IOPL mechanism would be used. 1262 1263config TOSHIBA 1264 tristate "Toshiba Laptop support" 1265 depends on X86_32 1266 help 1267 This adds a driver to safely access the System Management Mode of 1268 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1269 not work on models with a Phoenix BIOS. The System Management Mode 1270 is used to set the BIOS and power saving options on Toshiba portables. 1271 1272 For information on utilities to make use of this driver see the 1273 Toshiba Linux utilities web site at: 1274 <http://www.buzzard.org.uk/toshiba/>. 1275 1276 Say Y if you intend to run this kernel on a Toshiba portable. 1277 Say N otherwise. 1278 1279config I8K 1280 tristate "Dell i8k legacy laptop support" 1281 depends on HWMON 1282 depends on PROC_FS 1283 select SENSORS_DELL_SMM 1284 help 1285 This option enables legacy /proc/i8k userspace interface in hwmon 1286 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1287 temperature and allows controlling fan speeds of Dell laptops via 1288 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1289 it reports also power and hotkey status. For fan speed control is 1290 needed userspace package i8kutils. 1291 1292 Say Y if you intend to run this kernel on old Dell laptops or want to 1293 use userspace package i8kutils. 1294 Say N otherwise. 1295 1296config X86_REBOOTFIXUPS 1297 bool "Enable X86 board specific fixups for reboot" 1298 depends on X86_32 1299 help 1300 This enables chipset and/or board specific fixups to be done 1301 in order to get reboot to work correctly. This is only needed on 1302 some combinations of hardware and BIOS. The symptom, for which 1303 this config is intended, is when reboot ends with a stalled/hung 1304 system. 1305 1306 Currently, the only fixup is for the Geode machines using 1307 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1308 1309 Say Y if you want to enable the fixup. Currently, it's safe to 1310 enable this option even if you don't need it. 1311 Say N otherwise. 1312 1313config MICROCODE 1314 bool "CPU microcode loading support" 1315 default y 1316 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1317 help 1318 If you say Y here, you will be able to update the microcode on 1319 Intel and AMD processors. The Intel support is for the IA32 family, 1320 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1321 AMD support is for families 0x10 and later. You will obviously need 1322 the actual microcode binary data itself which is not shipped with 1323 the Linux kernel. 1324 1325 The preferred method to load microcode from a detached initrd is described 1326 in Documentation/x86/microcode.rst. For that you need to enable 1327 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1328 initrd for microcode blobs. 1329 1330 In addition, you can build the microcode into the kernel. For that you 1331 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1332 config option. 1333 1334config MICROCODE_INTEL 1335 bool "Intel microcode loading support" 1336 depends on MICROCODE 1337 default MICROCODE 1338 help 1339 This options enables microcode patch loading support for Intel 1340 processors. 1341 1342 For the current Intel microcode data package go to 1343 <https://downloadcenter.intel.com> and search for 1344 'Linux Processor Microcode Data File'. 1345 1346config MICROCODE_AMD 1347 bool "AMD microcode loading support" 1348 depends on MICROCODE 1349 help 1350 If you select this option, microcode patch loading support for AMD 1351 processors will be enabled. 1352 1353config MICROCODE_OLD_INTERFACE 1354 bool "Ancient loading interface (DEPRECATED)" 1355 default n 1356 depends on MICROCODE 1357 help 1358 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1359 which was used by userspace tools like iucode_tool and microcode.ctl. 1360 It is inadequate because it runs too late to be able to properly 1361 load microcode on a machine and it needs special tools. Instead, you 1362 should've switched to the early loading method with the initrd or 1363 builtin microcode by now: Documentation/x86/microcode.rst 1364 1365config X86_MSR 1366 tristate "/dev/cpu/*/msr - Model-specific register support" 1367 help 1368 This device gives privileged processes access to the x86 1369 Model-Specific Registers (MSRs). It is a character device with 1370 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1371 MSR accesses are directed to a specific CPU on multi-processor 1372 systems. 1373 1374config X86_CPUID 1375 tristate "/dev/cpu/*/cpuid - CPU information support" 1376 help 1377 This device gives processes access to the x86 CPUID instruction to 1378 be executed on a specific processor. It is a character device 1379 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1380 /dev/cpu/31/cpuid. 1381 1382choice 1383 prompt "High Memory Support" 1384 default HIGHMEM4G 1385 depends on X86_32 1386 1387config NOHIGHMEM 1388 bool "off" 1389 help 1390 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1391 However, the address space of 32-bit x86 processors is only 4 1392 Gigabytes large. That means that, if you have a large amount of 1393 physical memory, not all of it can be "permanently mapped" by the 1394 kernel. The physical memory that's not permanently mapped is called 1395 "high memory". 1396 1397 If you are compiling a kernel which will never run on a machine with 1398 more than 1 Gigabyte total physical RAM, answer "off" here (default 1399 choice and suitable for most users). This will result in a "3GB/1GB" 1400 split: 3GB are mapped so that each process sees a 3GB virtual memory 1401 space and the remaining part of the 4GB virtual memory space is used 1402 by the kernel to permanently map as much physical memory as 1403 possible. 1404 1405 If the machine has between 1 and 4 Gigabytes physical RAM, then 1406 answer "4GB" here. 1407 1408 If more than 4 Gigabytes is used then answer "64GB" here. This 1409 selection turns Intel PAE (Physical Address Extension) mode on. 1410 PAE implements 3-level paging on IA32 processors. PAE is fully 1411 supported by Linux, PAE mode is implemented on all recent Intel 1412 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1413 then the kernel will not boot on CPUs that don't support PAE! 1414 1415 The actual amount of total physical memory will either be 1416 auto detected or can be forced by using a kernel command line option 1417 such as "mem=256M". (Try "man bootparam" or see the documentation of 1418 your boot loader (lilo or loadlin) about how to pass options to the 1419 kernel at boot time.) 1420 1421 If unsure, say "off". 1422 1423config HIGHMEM4G 1424 bool "4GB" 1425 help 1426 Select this if you have a 32-bit processor and between 1 and 4 1427 gigabytes of physical RAM. 1428 1429config HIGHMEM64G 1430 bool "64GB" 1431 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1432 select X86_PAE 1433 help 1434 Select this if you have a 32-bit processor and more than 4 1435 gigabytes of physical RAM. 1436 1437endchoice 1438 1439choice 1440 prompt "Memory split" if EXPERT 1441 default VMSPLIT_3G 1442 depends on X86_32 1443 help 1444 Select the desired split between kernel and user memory. 1445 1446 If the address range available to the kernel is less than the 1447 physical memory installed, the remaining memory will be available 1448 as "high memory". Accessing high memory is a little more costly 1449 than low memory, as it needs to be mapped into the kernel first. 1450 Note that increasing the kernel address space limits the range 1451 available to user programs, making the address space there 1452 tighter. Selecting anything other than the default 3G/1G split 1453 will also likely make your kernel incompatible with binary-only 1454 kernel modules. 1455 1456 If you are not absolutely sure what you are doing, leave this 1457 option alone! 1458 1459 config VMSPLIT_3G 1460 bool "3G/1G user/kernel split" 1461 config VMSPLIT_3G_OPT 1462 depends on !X86_PAE 1463 bool "3G/1G user/kernel split (for full 1G low memory)" 1464 config VMSPLIT_2G 1465 bool "2G/2G user/kernel split" 1466 config VMSPLIT_2G_OPT 1467 depends on !X86_PAE 1468 bool "2G/2G user/kernel split (for full 2G low memory)" 1469 config VMSPLIT_1G 1470 bool "1G/3G user/kernel split" 1471endchoice 1472 1473config PAGE_OFFSET 1474 hex 1475 default 0xB0000000 if VMSPLIT_3G_OPT 1476 default 0x80000000 if VMSPLIT_2G 1477 default 0x78000000 if VMSPLIT_2G_OPT 1478 default 0x40000000 if VMSPLIT_1G 1479 default 0xC0000000 1480 depends on X86_32 1481 1482config HIGHMEM 1483 def_bool y 1484 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1485 1486config X86_PAE 1487 bool "PAE (Physical Address Extension) Support" 1488 depends on X86_32 && !HIGHMEM4G 1489 select PHYS_ADDR_T_64BIT 1490 select SWIOTLB 1491 help 1492 PAE is required for NX support, and furthermore enables 1493 larger swapspace support for non-overcommit purposes. It 1494 has the cost of more pagetable lookup overhead, and also 1495 consumes more pagetable space per process. 1496 1497config X86_5LEVEL 1498 bool "Enable 5-level page tables support" 1499 default y 1500 select DYNAMIC_MEMORY_LAYOUT 1501 select SPARSEMEM_VMEMMAP 1502 depends on X86_64 1503 help 1504 5-level paging enables access to larger address space: 1505 upto 128 PiB of virtual address space and 4 PiB of 1506 physical address space. 1507 1508 It will be supported by future Intel CPUs. 1509 1510 A kernel with the option enabled can be booted on machines that 1511 support 4- or 5-level paging. 1512 1513 See Documentation/x86/x86_64/5level-paging.rst for more 1514 information. 1515 1516 Say N if unsure. 1517 1518config X86_DIRECT_GBPAGES 1519 def_bool y 1520 depends on X86_64 1521 help 1522 Certain kernel features effectively disable kernel 1523 linear 1 GB mappings (even if the CPU otherwise 1524 supports them), so don't confuse the user by printing 1525 that we have them enabled. 1526 1527config X86_CPA_STATISTICS 1528 bool "Enable statistic for Change Page Attribute" 1529 depends on DEBUG_FS 1530 help 1531 Expose statistics about the Change Page Attribute mechanism, which 1532 helps to determine the effectiveness of preserving large and huge 1533 page mappings when mapping protections are changed. 1534 1535config X86_MEM_ENCRYPT 1536 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1537 select DYNAMIC_PHYSICAL_MASK 1538 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 1539 def_bool n 1540 1541config AMD_MEM_ENCRYPT 1542 bool "AMD Secure Memory Encryption (SME) support" 1543 depends on X86_64 && CPU_SUP_AMD 1544 select DMA_COHERENT_POOL 1545 select ARCH_USE_MEMREMAP_PROT 1546 select INSTRUCTION_DECODER 1547 select ARCH_HAS_CC_PLATFORM 1548 select X86_MEM_ENCRYPT 1549 help 1550 Say yes to enable support for the encryption of system memory. 1551 This requires an AMD processor that supports Secure Memory 1552 Encryption (SME). 1553 1554config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1555 bool "Activate AMD Secure Memory Encryption (SME) by default" 1556 depends on AMD_MEM_ENCRYPT 1557 help 1558 Say yes to have system memory encrypted by default if running on 1559 an AMD processor that supports Secure Memory Encryption (SME). 1560 1561 If set to Y, then the encryption of system memory can be 1562 deactivated with the mem_encrypt=off command line option. 1563 1564 If set to N, then the encryption of system memory can be 1565 activated with the mem_encrypt=on command line option. 1566 1567# Common NUMA Features 1568config NUMA 1569 bool "NUMA Memory Allocation and Scheduler Support" 1570 depends on SMP 1571 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1572 default y if X86_BIGSMP 1573 select USE_PERCPU_NUMA_NODE_ID 1574 help 1575 Enable NUMA (Non-Uniform Memory Access) support. 1576 1577 The kernel will try to allocate memory used by a CPU on the 1578 local memory controller of the CPU and add some more 1579 NUMA awareness to the kernel. 1580 1581 For 64-bit this is recommended if the system is Intel Core i7 1582 (or later), AMD Opteron, or EM64T NUMA. 1583 1584 For 32-bit this is only needed if you boot a 32-bit 1585 kernel on a 64-bit NUMA platform. 1586 1587 Otherwise, you should say N. 1588 1589config AMD_NUMA 1590 def_bool y 1591 prompt "Old style AMD Opteron NUMA detection" 1592 depends on X86_64 && NUMA && PCI 1593 help 1594 Enable AMD NUMA node topology detection. You should say Y here if 1595 you have a multi processor AMD system. This uses an old method to 1596 read the NUMA configuration directly from the builtin Northbridge 1597 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1598 which also takes priority if both are compiled in. 1599 1600config X86_64_ACPI_NUMA 1601 def_bool y 1602 prompt "ACPI NUMA detection" 1603 depends on X86_64 && NUMA && ACPI && PCI 1604 select ACPI_NUMA 1605 help 1606 Enable ACPI SRAT based node topology detection. 1607 1608config NUMA_EMU 1609 bool "NUMA emulation" 1610 depends on NUMA 1611 help 1612 Enable NUMA emulation. A flat machine will be split 1613 into virtual nodes when booted with "numa=fake=N", where N is the 1614 number of nodes. This is only useful for debugging. 1615 1616config NODES_SHIFT 1617 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1618 range 1 10 1619 default "10" if MAXSMP 1620 default "6" if X86_64 1621 default "3" 1622 depends on NUMA 1623 help 1624 Specify the maximum number of NUMA Nodes available on the target 1625 system. Increases memory reserved to accommodate various tables. 1626 1627config ARCH_FLATMEM_ENABLE 1628 def_bool y 1629 depends on X86_32 && !NUMA 1630 1631config ARCH_SPARSEMEM_ENABLE 1632 def_bool y 1633 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1634 select SPARSEMEM_STATIC if X86_32 1635 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1636 1637config ARCH_SPARSEMEM_DEFAULT 1638 def_bool X86_64 || (NUMA && X86_32) 1639 1640config ARCH_SELECT_MEMORY_MODEL 1641 def_bool y 1642 depends on ARCH_SPARSEMEM_ENABLE 1643 1644config ARCH_MEMORY_PROBE 1645 bool "Enable sysfs memory/probe interface" 1646 depends on MEMORY_HOTPLUG 1647 help 1648 This option enables a sysfs memory/probe interface for testing. 1649 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1650 If you are unsure how to answer this question, answer N. 1651 1652config ARCH_PROC_KCORE_TEXT 1653 def_bool y 1654 depends on X86_64 && PROC_KCORE 1655 1656config ILLEGAL_POINTER_VALUE 1657 hex 1658 default 0 if X86_32 1659 default 0xdead000000000000 if X86_64 1660 1661config X86_PMEM_LEGACY_DEVICE 1662 bool 1663 1664config X86_PMEM_LEGACY 1665 tristate "Support non-standard NVDIMMs and ADR protected memory" 1666 depends on PHYS_ADDR_T_64BIT 1667 depends on BLK_DEV 1668 select X86_PMEM_LEGACY_DEVICE 1669 select NUMA_KEEP_MEMINFO if NUMA 1670 select LIBNVDIMM 1671 help 1672 Treat memory marked using the non-standard e820 type of 12 as used 1673 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1674 The kernel will offer these regions to the 'pmem' driver so 1675 they can be used for persistent storage. 1676 1677 Say Y if unsure. 1678 1679config HIGHPTE 1680 bool "Allocate 3rd-level pagetables from highmem" 1681 depends on HIGHMEM 1682 help 1683 The VM uses one page table entry for each page of physical memory. 1684 For systems with a lot of RAM, this can be wasteful of precious 1685 low memory. Setting this option will put user-space page table 1686 entries in high memory. 1687 1688config X86_CHECK_BIOS_CORRUPTION 1689 bool "Check for low memory corruption" 1690 help 1691 Periodically check for memory corruption in low memory, which 1692 is suspected to be caused by BIOS. Even when enabled in the 1693 configuration, it is disabled at runtime. Enable it by 1694 setting "memory_corruption_check=1" on the kernel command 1695 line. By default it scans the low 64k of memory every 60 1696 seconds; see the memory_corruption_check_size and 1697 memory_corruption_check_period parameters in 1698 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1699 1700 When enabled with the default parameters, this option has 1701 almost no overhead, as it reserves a relatively small amount 1702 of memory and scans it infrequently. It both detects corruption 1703 and prevents it from affecting the running system. 1704 1705 It is, however, intended as a diagnostic tool; if repeatable 1706 BIOS-originated corruption always affects the same memory, 1707 you can use memmap= to prevent the kernel from using that 1708 memory. 1709 1710config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1711 bool "Set the default setting of memory_corruption_check" 1712 depends on X86_CHECK_BIOS_CORRUPTION 1713 default y 1714 help 1715 Set whether the default state of memory_corruption_check is 1716 on or off. 1717 1718config MATH_EMULATION 1719 bool 1720 depends on MODIFY_LDT_SYSCALL 1721 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1722 help 1723 Linux can emulate a math coprocessor (used for floating point 1724 operations) if you don't have one. 486DX and Pentium processors have 1725 a math coprocessor built in, 486SX and 386 do not, unless you added 1726 a 487DX or 387, respectively. (The messages during boot time can 1727 give you some hints here ["man dmesg"].) Everyone needs either a 1728 coprocessor or this emulation. 1729 1730 If you don't have a math coprocessor, you need to say Y here; if you 1731 say Y here even though you have a coprocessor, the coprocessor will 1732 be used nevertheless. (This behavior can be changed with the kernel 1733 command line option "no387", which comes handy if your coprocessor 1734 is broken. Try "man bootparam" or see the documentation of your boot 1735 loader (lilo or loadlin) about how to pass options to the kernel at 1736 boot time.) This means that it is a good idea to say Y here if you 1737 intend to use this kernel on different machines. 1738 1739 More information about the internals of the Linux math coprocessor 1740 emulation can be found in <file:arch/x86/math-emu/README>. 1741 1742 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1743 kernel, it won't hurt. 1744 1745config MTRR 1746 def_bool y 1747 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1748 help 1749 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1750 the Memory Type Range Registers (MTRRs) may be used to control 1751 processor access to memory ranges. This is most useful if you have 1752 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1753 allows bus write transfers to be combined into a larger transfer 1754 before bursting over the PCI/AGP bus. This can increase performance 1755 of image write operations 2.5 times or more. Saying Y here creates a 1756 /proc/mtrr file which may be used to manipulate your processor's 1757 MTRRs. Typically the X server should use this. 1758 1759 This code has a reasonably generic interface so that similar 1760 control registers on other processors can be easily supported 1761 as well: 1762 1763 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1764 Registers (ARRs) which provide a similar functionality to MTRRs. For 1765 these, the ARRs are used to emulate the MTRRs. 1766 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1767 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1768 write-combining. All of these processors are supported by this code 1769 and it makes sense to say Y here if you have one of them. 1770 1771 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1772 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1773 can lead to all sorts of problems, so it's good to say Y here. 1774 1775 You can safely say Y even if your machine doesn't have MTRRs, you'll 1776 just add about 9 KB to your kernel. 1777 1778 See <file:Documentation/x86/mtrr.rst> for more information. 1779 1780config MTRR_SANITIZER 1781 def_bool y 1782 prompt "MTRR cleanup support" 1783 depends on MTRR 1784 help 1785 Convert MTRR layout from continuous to discrete, so X drivers can 1786 add writeback entries. 1787 1788 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1789 The largest mtrr entry size for a continuous block can be set with 1790 mtrr_chunk_size. 1791 1792 If unsure, say Y. 1793 1794config MTRR_SANITIZER_ENABLE_DEFAULT 1795 int "MTRR cleanup enable value (0-1)" 1796 range 0 1 1797 default "0" 1798 depends on MTRR_SANITIZER 1799 help 1800 Enable mtrr cleanup default value 1801 1802config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1803 int "MTRR cleanup spare reg num (0-7)" 1804 range 0 7 1805 default "1" 1806 depends on MTRR_SANITIZER 1807 help 1808 mtrr cleanup spare entries default, it can be changed via 1809 mtrr_spare_reg_nr=N on the kernel command line. 1810 1811config X86_PAT 1812 def_bool y 1813 prompt "x86 PAT support" if EXPERT 1814 depends on MTRR 1815 help 1816 Use PAT attributes to setup page level cache control. 1817 1818 PATs are the modern equivalents of MTRRs and are much more 1819 flexible than MTRRs. 1820 1821 Say N here if you see bootup problems (boot crash, boot hang, 1822 spontaneous reboots) or a non-working video driver. 1823 1824 If unsure, say Y. 1825 1826config ARCH_USES_PG_UNCACHED 1827 def_bool y 1828 depends on X86_PAT 1829 1830config ARCH_RANDOM 1831 def_bool y 1832 prompt "x86 architectural random number generator" if EXPERT 1833 help 1834 Enable the x86 architectural RDRAND instruction 1835 (Intel Bull Mountain technology) to generate random numbers. 1836 If supported, this is a high bandwidth, cryptographically 1837 secure hardware random number generator. 1838 1839config X86_SMAP 1840 def_bool y 1841 prompt "Supervisor Mode Access Prevention" if EXPERT 1842 help 1843 Supervisor Mode Access Prevention (SMAP) is a security 1844 feature in newer Intel processors. There is a small 1845 performance cost if this enabled and turned on; there is 1846 also a small increase in the kernel size if this is enabled. 1847 1848 If unsure, say Y. 1849 1850config X86_UMIP 1851 def_bool y 1852 prompt "User Mode Instruction Prevention" if EXPERT 1853 help 1854 User Mode Instruction Prevention (UMIP) is a security feature in 1855 some x86 processors. If enabled, a general protection fault is 1856 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1857 executed in user mode. These instructions unnecessarily expose 1858 information about the hardware state. 1859 1860 The vast majority of applications do not use these instructions. 1861 For the very few that do, software emulation is provided in 1862 specific cases in protected and virtual-8086 modes. Emulated 1863 results are dummy. 1864 1865config X86_INTEL_MEMORY_PROTECTION_KEYS 1866 prompt "Memory Protection Keys" 1867 def_bool y 1868 # Note: only available in 64-bit mode 1869 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1870 select ARCH_USES_HIGH_VMA_FLAGS 1871 select ARCH_HAS_PKEYS 1872 help 1873 Memory Protection Keys provides a mechanism for enforcing 1874 page-based protections, but without requiring modification of the 1875 page tables when an application changes protection domains. 1876 1877 For details, see Documentation/core-api/protection-keys.rst 1878 1879 If unsure, say y. 1880 1881choice 1882 prompt "TSX enable mode" 1883 depends on CPU_SUP_INTEL 1884 default X86_INTEL_TSX_MODE_OFF 1885 help 1886 Intel's TSX (Transactional Synchronization Extensions) feature 1887 allows to optimize locking protocols through lock elision which 1888 can lead to a noticeable performance boost. 1889 1890 On the other hand it has been shown that TSX can be exploited 1891 to form side channel attacks (e.g. TAA) and chances are there 1892 will be more of those attacks discovered in the future. 1893 1894 Therefore TSX is not enabled by default (aka tsx=off). An admin 1895 might override this decision by tsx=on the command line parameter. 1896 Even with TSX enabled, the kernel will attempt to enable the best 1897 possible TAA mitigation setting depending on the microcode available 1898 for the particular machine. 1899 1900 This option allows to set the default tsx mode between tsx=on, =off 1901 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1902 details. 1903 1904 Say off if not sure, auto if TSX is in use but it should be used on safe 1905 platforms or on if TSX is in use and the security aspect of tsx is not 1906 relevant. 1907 1908config X86_INTEL_TSX_MODE_OFF 1909 bool "off" 1910 help 1911 TSX is disabled if possible - equals to tsx=off command line parameter. 1912 1913config X86_INTEL_TSX_MODE_ON 1914 bool "on" 1915 help 1916 TSX is always enabled on TSX capable HW - equals the tsx=on command 1917 line parameter. 1918 1919config X86_INTEL_TSX_MODE_AUTO 1920 bool "auto" 1921 help 1922 TSX is enabled on TSX capable HW that is believed to be safe against 1923 side channel attacks- equals the tsx=auto command line parameter. 1924endchoice 1925 1926config X86_SGX 1927 bool "Software Guard eXtensions (SGX)" 1928 depends on X86_64 && CPU_SUP_INTEL 1929 depends on CRYPTO=y 1930 depends on CRYPTO_SHA256=y 1931 select SRCU 1932 select MMU_NOTIFIER 1933 select NUMA_KEEP_MEMINFO if NUMA 1934 select XARRAY_MULTI 1935 help 1936 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1937 that can be used by applications to set aside private regions of code 1938 and data, referred to as enclaves. An enclave's private memory can 1939 only be accessed by code running within the enclave. Accesses from 1940 outside the enclave, including other enclaves, are disallowed by 1941 hardware. 1942 1943 If unsure, say N. 1944 1945config EFI 1946 bool "EFI runtime service support" 1947 depends on ACPI 1948 select UCS2_STRING 1949 select EFI_RUNTIME_WRAPPERS 1950 select ARCH_USE_MEMREMAP_PROT 1951 help 1952 This enables the kernel to use EFI runtime services that are 1953 available (such as the EFI variable services). 1954 1955 This option is only useful on systems that have EFI firmware. 1956 In addition, you should use the latest ELILO loader available 1957 at <http://elilo.sourceforge.net> in order to take advantage 1958 of EFI runtime services. However, even with this option, the 1959 resultant kernel should continue to boot on existing non-EFI 1960 platforms. 1961 1962config EFI_STUB 1963 bool "EFI stub support" 1964 depends on EFI 1965 depends on $(cc-option,-mabi=ms) || X86_32 1966 select RELOCATABLE 1967 help 1968 This kernel feature allows a bzImage to be loaded directly 1969 by EFI firmware without the use of a bootloader. 1970 1971 See Documentation/admin-guide/efi-stub.rst for more information. 1972 1973config EFI_MIXED 1974 bool "EFI mixed-mode support" 1975 depends on EFI_STUB && X86_64 1976 help 1977 Enabling this feature allows a 64-bit kernel to be booted 1978 on a 32-bit firmware, provided that your CPU supports 64-bit 1979 mode. 1980 1981 Note that it is not possible to boot a mixed-mode enabled 1982 kernel via the EFI boot stub - a bootloader that supports 1983 the EFI handover protocol must be used. 1984 1985 If unsure, say N. 1986 1987source "kernel/Kconfig.hz" 1988 1989config KEXEC 1990 bool "kexec system call" 1991 select KEXEC_CORE 1992 help 1993 kexec is a system call that implements the ability to shutdown your 1994 current kernel, and to start another kernel. It is like a reboot 1995 but it is independent of the system firmware. And like a reboot 1996 you can start any kernel with it, not just Linux. 1997 1998 The name comes from the similarity to the exec system call. 1999 2000 It is an ongoing process to be certain the hardware in a machine 2001 is properly shutdown, so do not be surprised if this code does not 2002 initially work for you. As of this writing the exact hardware 2003 interface is strongly in flux, so no good recommendation can be 2004 made. 2005 2006config KEXEC_FILE 2007 bool "kexec file based system call" 2008 select KEXEC_CORE 2009 select BUILD_BIN2C 2010 depends on X86_64 2011 depends on CRYPTO=y 2012 depends on CRYPTO_SHA256=y 2013 help 2014 This is new version of kexec system call. This system call is 2015 file based and takes file descriptors as system call argument 2016 for kernel and initramfs as opposed to list of segments as 2017 accepted by previous system call. 2018 2019config ARCH_HAS_KEXEC_PURGATORY 2020 def_bool KEXEC_FILE 2021 2022config KEXEC_SIG 2023 bool "Verify kernel signature during kexec_file_load() syscall" 2024 depends on KEXEC_FILE 2025 help 2026 2027 This option makes the kexec_file_load() syscall check for a valid 2028 signature of the kernel image. The image can still be loaded without 2029 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2030 there's a signature that we can check, then it must be valid. 2031 2032 In addition to this option, you need to enable signature 2033 verification for the corresponding kernel image type being 2034 loaded in order for this to work. 2035 2036config KEXEC_SIG_FORCE 2037 bool "Require a valid signature in kexec_file_load() syscall" 2038 depends on KEXEC_SIG 2039 help 2040 This option makes kernel signature verification mandatory for 2041 the kexec_file_load() syscall. 2042 2043config KEXEC_BZIMAGE_VERIFY_SIG 2044 bool "Enable bzImage signature verification support" 2045 depends on KEXEC_SIG 2046 depends on SIGNED_PE_FILE_VERIFICATION 2047 select SYSTEM_TRUSTED_KEYRING 2048 help 2049 Enable bzImage signature verification support. 2050 2051config CRASH_DUMP 2052 bool "kernel crash dumps" 2053 depends on X86_64 || (X86_32 && HIGHMEM) 2054 help 2055 Generate crash dump after being started by kexec. 2056 This should be normally only set in special crash dump kernels 2057 which are loaded in the main kernel with kexec-tools into 2058 a specially reserved region and then later executed after 2059 a crash by kdump/kexec. The crash dump kernel must be compiled 2060 to a memory address not used by the main kernel or BIOS using 2061 PHYSICAL_START, or it must be built as a relocatable image 2062 (CONFIG_RELOCATABLE=y). 2063 For more details see Documentation/admin-guide/kdump/kdump.rst 2064 2065config KEXEC_JUMP 2066 bool "kexec jump" 2067 depends on KEXEC && HIBERNATION 2068 help 2069 Jump between original kernel and kexeced kernel and invoke 2070 code in physical address mode via KEXEC 2071 2072config PHYSICAL_START 2073 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2074 default "0x1000000" 2075 help 2076 This gives the physical address where the kernel is loaded. 2077 2078 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2079 bzImage will decompress itself to above physical address and 2080 run from there. Otherwise, bzImage will run from the address where 2081 it has been loaded by the boot loader and will ignore above physical 2082 address. 2083 2084 In normal kdump cases one does not have to set/change this option 2085 as now bzImage can be compiled as a completely relocatable image 2086 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2087 address. This option is mainly useful for the folks who don't want 2088 to use a bzImage for capturing the crash dump and want to use a 2089 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2090 to be specifically compiled to run from a specific memory area 2091 (normally a reserved region) and this option comes handy. 2092 2093 So if you are using bzImage for capturing the crash dump, 2094 leave the value here unchanged to 0x1000000 and set 2095 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2096 for capturing the crash dump change this value to start of 2097 the reserved region. In other words, it can be set based on 2098 the "X" value as specified in the "crashkernel=YM@XM" 2099 command line boot parameter passed to the panic-ed 2100 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2101 for more details about crash dumps. 2102 2103 Usage of bzImage for capturing the crash dump is recommended as 2104 one does not have to build two kernels. Same kernel can be used 2105 as production kernel and capture kernel. Above option should have 2106 gone away after relocatable bzImage support is introduced. But it 2107 is present because there are users out there who continue to use 2108 vmlinux for dump capture. This option should go away down the 2109 line. 2110 2111 Don't change this unless you know what you are doing. 2112 2113config RELOCATABLE 2114 bool "Build a relocatable kernel" 2115 default y 2116 help 2117 This builds a kernel image that retains relocation information 2118 so it can be loaded someplace besides the default 1MB. 2119 The relocations tend to make the kernel binary about 10% larger, 2120 but are discarded at runtime. 2121 2122 One use is for the kexec on panic case where the recovery kernel 2123 must live at a different physical address than the primary 2124 kernel. 2125 2126 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2127 it has been loaded at and the compile time physical address 2128 (CONFIG_PHYSICAL_START) is used as the minimum location. 2129 2130config RANDOMIZE_BASE 2131 bool "Randomize the address of the kernel image (KASLR)" 2132 depends on RELOCATABLE 2133 default y 2134 help 2135 In support of Kernel Address Space Layout Randomization (KASLR), 2136 this randomizes the physical address at which the kernel image 2137 is decompressed and the virtual address where the kernel 2138 image is mapped, as a security feature that deters exploit 2139 attempts relying on knowledge of the location of kernel 2140 code internals. 2141 2142 On 64-bit, the kernel physical and virtual addresses are 2143 randomized separately. The physical address will be anywhere 2144 between 16MB and the top of physical memory (up to 64TB). The 2145 virtual address will be randomized from 16MB up to 1GB (9 bits 2146 of entropy). Note that this also reduces the memory space 2147 available to kernel modules from 1.5GB to 1GB. 2148 2149 On 32-bit, the kernel physical and virtual addresses are 2150 randomized together. They will be randomized from 16MB up to 2151 512MB (8 bits of entropy). 2152 2153 Entropy is generated using the RDRAND instruction if it is 2154 supported. If RDTSC is supported, its value is mixed into 2155 the entropy pool as well. If neither RDRAND nor RDTSC are 2156 supported, then entropy is read from the i8254 timer. The 2157 usable entropy is limited by the kernel being built using 2158 2GB addressing, and that PHYSICAL_ALIGN must be at a 2159 minimum of 2MB. As a result, only 10 bits of entropy are 2160 theoretically possible, but the implementations are further 2161 limited due to memory layouts. 2162 2163 If unsure, say Y. 2164 2165# Relocation on x86 needs some additional build support 2166config X86_NEED_RELOCS 2167 def_bool y 2168 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2169 2170config PHYSICAL_ALIGN 2171 hex "Alignment value to which kernel should be aligned" 2172 default "0x200000" 2173 range 0x2000 0x1000000 if X86_32 2174 range 0x200000 0x1000000 if X86_64 2175 help 2176 This value puts the alignment restrictions on physical address 2177 where kernel is loaded and run from. Kernel is compiled for an 2178 address which meets above alignment restriction. 2179 2180 If bootloader loads the kernel at a non-aligned address and 2181 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2182 address aligned to above value and run from there. 2183 2184 If bootloader loads the kernel at a non-aligned address and 2185 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2186 load address and decompress itself to the address it has been 2187 compiled for and run from there. The address for which kernel is 2188 compiled already meets above alignment restrictions. Hence the 2189 end result is that kernel runs from a physical address meeting 2190 above alignment restrictions. 2191 2192 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2193 this value must be a multiple of 0x200000. 2194 2195 Don't change this unless you know what you are doing. 2196 2197config DYNAMIC_MEMORY_LAYOUT 2198 bool 2199 help 2200 This option makes base addresses of vmalloc and vmemmap as well as 2201 __PAGE_OFFSET movable during boot. 2202 2203config RANDOMIZE_MEMORY 2204 bool "Randomize the kernel memory sections" 2205 depends on X86_64 2206 depends on RANDOMIZE_BASE 2207 select DYNAMIC_MEMORY_LAYOUT 2208 default RANDOMIZE_BASE 2209 help 2210 Randomizes the base virtual address of kernel memory sections 2211 (physical memory mapping, vmalloc & vmemmap). This security feature 2212 makes exploits relying on predictable memory locations less reliable. 2213 2214 The order of allocations remains unchanged. Entropy is generated in 2215 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2216 configuration have in average 30,000 different possible virtual 2217 addresses for each memory section. 2218 2219 If unsure, say Y. 2220 2221config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2222 hex "Physical memory mapping padding" if EXPERT 2223 depends on RANDOMIZE_MEMORY 2224 default "0xa" if MEMORY_HOTPLUG 2225 default "0x0" 2226 range 0x1 0x40 if MEMORY_HOTPLUG 2227 range 0x0 0x40 2228 help 2229 Define the padding in terabytes added to the existing physical 2230 memory size during kernel memory randomization. It is useful 2231 for memory hotplug support but reduces the entropy available for 2232 address randomization. 2233 2234 If unsure, leave at the default value. 2235 2236config HOTPLUG_CPU 2237 def_bool y 2238 depends on SMP 2239 2240config BOOTPARAM_HOTPLUG_CPU0 2241 bool "Set default setting of cpu0_hotpluggable" 2242 depends on HOTPLUG_CPU 2243 help 2244 Set whether default state of cpu0_hotpluggable is on or off. 2245 2246 Say Y here to enable CPU0 hotplug by default. If this switch 2247 is turned on, there is no need to give cpu0_hotplug kernel 2248 parameter and the CPU0 hotplug feature is enabled by default. 2249 2250 Please note: there are two known CPU0 dependencies if you want 2251 to enable the CPU0 hotplug feature either by this switch or by 2252 cpu0_hotplug kernel parameter. 2253 2254 First, resume from hibernate or suspend always starts from CPU0. 2255 So hibernate and suspend are prevented if CPU0 is offline. 2256 2257 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2258 offline if any interrupt can not migrate out of CPU0. There may 2259 be other CPU0 dependencies. 2260 2261 Please make sure the dependencies are under your control before 2262 you enable this feature. 2263 2264 Say N if you don't want to enable CPU0 hotplug feature by default. 2265 You still can enable the CPU0 hotplug feature at boot by kernel 2266 parameter cpu0_hotplug. 2267 2268config DEBUG_HOTPLUG_CPU0 2269 def_bool n 2270 prompt "Debug CPU0 hotplug" 2271 depends on HOTPLUG_CPU 2272 help 2273 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2274 soon as possible and boots up userspace with CPU0 offlined. User 2275 can online CPU0 back after boot time. 2276 2277 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2278 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2279 compilation or giving cpu0_hotplug kernel parameter at boot. 2280 2281 If unsure, say N. 2282 2283config COMPAT_VDSO 2284 def_bool n 2285 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2286 depends on COMPAT_32 2287 help 2288 Certain buggy versions of glibc will crash if they are 2289 presented with a 32-bit vDSO that is not mapped at the address 2290 indicated in its segment table. 2291 2292 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2293 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2294 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2295 the only released version with the bug, but OpenSUSE 9 2296 contains a buggy "glibc 2.3.2". 2297 2298 The symptom of the bug is that everything crashes on startup, saying: 2299 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2300 2301 Saying Y here changes the default value of the vdso32 boot 2302 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2303 This works around the glibc bug but hurts performance. 2304 2305 If unsure, say N: if you are compiling your own kernel, you 2306 are unlikely to be using a buggy version of glibc. 2307 2308choice 2309 prompt "vsyscall table for legacy applications" 2310 depends on X86_64 2311 default LEGACY_VSYSCALL_XONLY 2312 help 2313 Legacy user code that does not know how to find the vDSO expects 2314 to be able to issue three syscalls by calling fixed addresses in 2315 kernel space. Since this location is not randomized with ASLR, 2316 it can be used to assist security vulnerability exploitation. 2317 2318 This setting can be changed at boot time via the kernel command 2319 line parameter vsyscall=[emulate|xonly|none]. 2320 2321 On a system with recent enough glibc (2.14 or newer) and no 2322 static binaries, you can say None without a performance penalty 2323 to improve security. 2324 2325 If unsure, select "Emulate execution only". 2326 2327 config LEGACY_VSYSCALL_EMULATE 2328 bool "Full emulation" 2329 help 2330 The kernel traps and emulates calls into the fixed vsyscall 2331 address mapping. This makes the mapping non-executable, but 2332 it still contains readable known contents, which could be 2333 used in certain rare security vulnerability exploits. This 2334 configuration is recommended when using legacy userspace 2335 that still uses vsyscalls along with legacy binary 2336 instrumentation tools that require code to be readable. 2337 2338 An example of this type of legacy userspace is running 2339 Pin on an old binary that still uses vsyscalls. 2340 2341 config LEGACY_VSYSCALL_XONLY 2342 bool "Emulate execution only" 2343 help 2344 The kernel traps and emulates calls into the fixed vsyscall 2345 address mapping and does not allow reads. This 2346 configuration is recommended when userspace might use the 2347 legacy vsyscall area but support for legacy binary 2348 instrumentation of legacy code is not needed. It mitigates 2349 certain uses of the vsyscall area as an ASLR-bypassing 2350 buffer. 2351 2352 config LEGACY_VSYSCALL_NONE 2353 bool "None" 2354 help 2355 There will be no vsyscall mapping at all. This will 2356 eliminate any risk of ASLR bypass due to the vsyscall 2357 fixed address mapping. Attempts to use the vsyscalls 2358 will be reported to dmesg, so that either old or 2359 malicious userspace programs can be identified. 2360 2361endchoice 2362 2363config CMDLINE_BOOL 2364 bool "Built-in kernel command line" 2365 help 2366 Allow for specifying boot arguments to the kernel at 2367 build time. On some systems (e.g. embedded ones), it is 2368 necessary or convenient to provide some or all of the 2369 kernel boot arguments with the kernel itself (that is, 2370 to not rely on the boot loader to provide them.) 2371 2372 To compile command line arguments into the kernel, 2373 set this option to 'Y', then fill in the 2374 boot arguments in CONFIG_CMDLINE. 2375 2376 Systems with fully functional boot loaders (i.e. non-embedded) 2377 should leave this option set to 'N'. 2378 2379config CMDLINE 2380 string "Built-in kernel command string" 2381 depends on CMDLINE_BOOL 2382 default "" 2383 help 2384 Enter arguments here that should be compiled into the kernel 2385 image and used at boot time. If the boot loader provides a 2386 command line at boot time, it is appended to this string to 2387 form the full kernel command line, when the system boots. 2388 2389 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2390 change this behavior. 2391 2392 In most cases, the command line (whether built-in or provided 2393 by the boot loader) should specify the device for the root 2394 file system. 2395 2396config CMDLINE_OVERRIDE 2397 bool "Built-in command line overrides boot loader arguments" 2398 depends on CMDLINE_BOOL && CMDLINE != "" 2399 help 2400 Set this option to 'Y' to have the kernel ignore the boot loader 2401 command line, and use ONLY the built-in command line. 2402 2403 This is used to work around broken boot loaders. This should 2404 be set to 'N' under normal conditions. 2405 2406config MODIFY_LDT_SYSCALL 2407 bool "Enable the LDT (local descriptor table)" if EXPERT 2408 default y 2409 help 2410 Linux can allow user programs to install a per-process x86 2411 Local Descriptor Table (LDT) using the modify_ldt(2) system 2412 call. This is required to run 16-bit or segmented code such as 2413 DOSEMU or some Wine programs. It is also used by some very old 2414 threading libraries. 2415 2416 Enabling this feature adds a small amount of overhead to 2417 context switches and increases the low-level kernel attack 2418 surface. Disabling it removes the modify_ldt(2) system call. 2419 2420 Saying 'N' here may make sense for embedded or server kernels. 2421 2422config STRICT_SIGALTSTACK_SIZE 2423 bool "Enforce strict size checking for sigaltstack" 2424 depends on DYNAMIC_SIGFRAME 2425 help 2426 For historical reasons MINSIGSTKSZ is a constant which became 2427 already too small with AVX512 support. Add a mechanism to 2428 enforce strict checking of the sigaltstack size against the 2429 real size of the FPU frame. This option enables the check 2430 by default. It can also be controlled via the kernel command 2431 line option 'strict_sas_size' independent of this config 2432 switch. Enabling it might break existing applications which 2433 allocate a too small sigaltstack but 'work' because they 2434 never get a signal delivered. 2435 2436 Say 'N' unless you want to really enforce this check. 2437 2438source "kernel/livepatch/Kconfig" 2439 2440endmenu 2441 2442config ARCH_HAS_ADD_PAGES 2443 def_bool y 2444 depends on ARCH_ENABLE_MEMORY_HOTPLUG 2445 2446config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2447 def_bool y 2448 2449menu "Power management and ACPI options" 2450 2451config ARCH_HIBERNATION_HEADER 2452 def_bool y 2453 depends on HIBERNATION 2454 2455source "kernel/power/Kconfig" 2456 2457source "drivers/acpi/Kconfig" 2458 2459config X86_APM_BOOT 2460 def_bool y 2461 depends on APM 2462 2463menuconfig APM 2464 tristate "APM (Advanced Power Management) BIOS support" 2465 depends on X86_32 && PM_SLEEP 2466 help 2467 APM is a BIOS specification for saving power using several different 2468 techniques. This is mostly useful for battery powered laptops with 2469 APM compliant BIOSes. If you say Y here, the system time will be 2470 reset after a RESUME operation, the /proc/apm device will provide 2471 battery status information, and user-space programs will receive 2472 notification of APM "events" (e.g. battery status change). 2473 2474 If you select "Y" here, you can disable actual use of the APM 2475 BIOS by passing the "apm=off" option to the kernel at boot time. 2476 2477 Note that the APM support is almost completely disabled for 2478 machines with more than one CPU. 2479 2480 In order to use APM, you will need supporting software. For location 2481 and more information, read <file:Documentation/power/apm-acpi.rst> 2482 and the Battery Powered Linux mini-HOWTO, available from 2483 <http://www.tldp.org/docs.html#howto>. 2484 2485 This driver does not spin down disk drives (see the hdparm(8) 2486 manpage ("man 8 hdparm") for that), and it doesn't turn off 2487 VESA-compliant "green" monitors. 2488 2489 This driver does not support the TI 4000M TravelMate and the ACER 2490 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2491 desktop machines also don't have compliant BIOSes, and this driver 2492 may cause those machines to panic during the boot phase. 2493 2494 Generally, if you don't have a battery in your machine, there isn't 2495 much point in using this driver and you should say N. If you get 2496 random kernel OOPSes or reboots that don't seem to be related to 2497 anything, try disabling/enabling this option (or disabling/enabling 2498 APM in your BIOS). 2499 2500 Some other things you should try when experiencing seemingly random, 2501 "weird" problems: 2502 2503 1) make sure that you have enough swap space and that it is 2504 enabled. 2505 2) pass the "no-hlt" option to the kernel 2506 3) switch on floating point emulation in the kernel and pass 2507 the "no387" option to the kernel 2508 4) pass the "floppy=nodma" option to the kernel 2509 5) pass the "mem=4M" option to the kernel (thereby disabling 2510 all but the first 4 MB of RAM) 2511 6) make sure that the CPU is not over clocked. 2512 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2513 8) disable the cache from your BIOS settings 2514 9) install a fan for the video card or exchange video RAM 2515 10) install a better fan for the CPU 2516 11) exchange RAM chips 2517 12) exchange the motherboard. 2518 2519 To compile this driver as a module, choose M here: the 2520 module will be called apm. 2521 2522if APM 2523 2524config APM_IGNORE_USER_SUSPEND 2525 bool "Ignore USER SUSPEND" 2526 help 2527 This option will ignore USER SUSPEND requests. On machines with a 2528 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2529 series notebooks, it is necessary to say Y because of a BIOS bug. 2530 2531config APM_DO_ENABLE 2532 bool "Enable PM at boot time" 2533 help 2534 Enable APM features at boot time. From page 36 of the APM BIOS 2535 specification: "When disabled, the APM BIOS does not automatically 2536 power manage devices, enter the Standby State, enter the Suspend 2537 State, or take power saving steps in response to CPU Idle calls." 2538 This driver will make CPU Idle calls when Linux is idle (unless this 2539 feature is turned off -- see "Do CPU IDLE calls", below). This 2540 should always save battery power, but more complicated APM features 2541 will be dependent on your BIOS implementation. You may need to turn 2542 this option off if your computer hangs at boot time when using APM 2543 support, or if it beeps continuously instead of suspending. Turn 2544 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2545 T400CDT. This is off by default since most machines do fine without 2546 this feature. 2547 2548config APM_CPU_IDLE 2549 depends on CPU_IDLE 2550 bool "Make CPU Idle calls when idle" 2551 help 2552 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2553 On some machines, this can activate improved power savings, such as 2554 a slowed CPU clock rate, when the machine is idle. These idle calls 2555 are made after the idle loop has run for some length of time (e.g., 2556 333 mS). On some machines, this will cause a hang at boot time or 2557 whenever the CPU becomes idle. (On machines with more than one CPU, 2558 this option does nothing.) 2559 2560config APM_DISPLAY_BLANK 2561 bool "Enable console blanking using APM" 2562 help 2563 Enable console blanking using the APM. Some laptops can use this to 2564 turn off the LCD backlight when the screen blanker of the Linux 2565 virtual console blanks the screen. Note that this is only used by 2566 the virtual console screen blanker, and won't turn off the backlight 2567 when using the X Window system. This also doesn't have anything to 2568 do with your VESA-compliant power-saving monitor. Further, this 2569 option doesn't work for all laptops -- it might not turn off your 2570 backlight at all, or it might print a lot of errors to the console, 2571 especially if you are using gpm. 2572 2573config APM_ALLOW_INTS 2574 bool "Allow interrupts during APM BIOS calls" 2575 help 2576 Normally we disable external interrupts while we are making calls to 2577 the APM BIOS as a measure to lessen the effects of a badly behaving 2578 BIOS implementation. The BIOS should reenable interrupts if it 2579 needs to. Unfortunately, some BIOSes do not -- especially those in 2580 many of the newer IBM Thinkpads. If you experience hangs when you 2581 suspend, try setting this to Y. Otherwise, say N. 2582 2583endif # APM 2584 2585source "drivers/cpufreq/Kconfig" 2586 2587source "drivers/cpuidle/Kconfig" 2588 2589source "drivers/idle/Kconfig" 2590 2591endmenu 2592 2593 2594menu "Bus options (PCI etc.)" 2595 2596choice 2597 prompt "PCI access mode" 2598 depends on X86_32 && PCI 2599 default PCI_GOANY 2600 help 2601 On PCI systems, the BIOS can be used to detect the PCI devices and 2602 determine their configuration. However, some old PCI motherboards 2603 have BIOS bugs and may crash if this is done. Also, some embedded 2604 PCI-based systems don't have any BIOS at all. Linux can also try to 2605 detect the PCI hardware directly without using the BIOS. 2606 2607 With this option, you can specify how Linux should detect the 2608 PCI devices. If you choose "BIOS", the BIOS will be used, 2609 if you choose "Direct", the BIOS won't be used, and if you 2610 choose "MMConfig", then PCI Express MMCONFIG will be used. 2611 If you choose "Any", the kernel will try MMCONFIG, then the 2612 direct access method and falls back to the BIOS if that doesn't 2613 work. If unsure, go with the default, which is "Any". 2614 2615config PCI_GOBIOS 2616 bool "BIOS" 2617 2618config PCI_GOMMCONFIG 2619 bool "MMConfig" 2620 2621config PCI_GODIRECT 2622 bool "Direct" 2623 2624config PCI_GOOLPC 2625 bool "OLPC XO-1" 2626 depends on OLPC 2627 2628config PCI_GOANY 2629 bool "Any" 2630 2631endchoice 2632 2633config PCI_BIOS 2634 def_bool y 2635 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2636 2637# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2638config PCI_DIRECT 2639 def_bool y 2640 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2641 2642config PCI_MMCONFIG 2643 bool "Support mmconfig PCI config space access" if X86_64 2644 default y 2645 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2646 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2647 2648config PCI_OLPC 2649 def_bool y 2650 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2651 2652config PCI_XEN 2653 def_bool y 2654 depends on PCI && XEN 2655 2656config MMCONF_FAM10H 2657 def_bool y 2658 depends on X86_64 && PCI_MMCONFIG && ACPI 2659 2660config PCI_CNB20LE_QUIRK 2661 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2662 depends on PCI 2663 help 2664 Read the PCI windows out of the CNB20LE host bridge. This allows 2665 PCI hotplug to work on systems with the CNB20LE chipset which do 2666 not have ACPI. 2667 2668 There's no public spec for this chipset, and this functionality 2669 is known to be incomplete. 2670 2671 You should say N unless you know you need this. 2672 2673config ISA_BUS 2674 bool "ISA bus support on modern systems" if EXPERT 2675 help 2676 Expose ISA bus device drivers and options available for selection and 2677 configuration. Enable this option if your target machine has an ISA 2678 bus. ISA is an older system, displaced by PCI and newer bus 2679 architectures -- if your target machine is modern, it probably does 2680 not have an ISA bus. 2681 2682 If unsure, say N. 2683 2684# x86_64 have no ISA slots, but can have ISA-style DMA. 2685config ISA_DMA_API 2686 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2687 default y 2688 help 2689 Enables ISA-style DMA support for devices requiring such controllers. 2690 If unsure, say Y. 2691 2692if X86_32 2693 2694config ISA 2695 bool "ISA support" 2696 help 2697 Find out whether you have ISA slots on your motherboard. ISA is the 2698 name of a bus system, i.e. the way the CPU talks to the other stuff 2699 inside your box. Other bus systems are PCI, EISA, MicroChannel 2700 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2701 newer boards don't support it. If you have ISA, say Y, otherwise N. 2702 2703config SCx200 2704 tristate "NatSemi SCx200 support" 2705 help 2706 This provides basic support for National Semiconductor's 2707 (now AMD's) Geode processors. The driver probes for the 2708 PCI-IDs of several on-chip devices, so its a good dependency 2709 for other scx200_* drivers. 2710 2711 If compiled as a module, the driver is named scx200. 2712 2713config SCx200HR_TIMER 2714 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2715 depends on SCx200 2716 default y 2717 help 2718 This driver provides a clocksource built upon the on-chip 2719 27MHz high-resolution timer. Its also a workaround for 2720 NSC Geode SC-1100's buggy TSC, which loses time when the 2721 processor goes idle (as is done by the scheduler). The 2722 other workaround is idle=poll boot option. 2723 2724config OLPC 2725 bool "One Laptop Per Child support" 2726 depends on !X86_PAE 2727 select GPIOLIB 2728 select OF 2729 select OF_PROMTREE 2730 select IRQ_DOMAIN 2731 select OLPC_EC 2732 help 2733 Add support for detecting the unique features of the OLPC 2734 XO hardware. 2735 2736config OLPC_XO1_PM 2737 bool "OLPC XO-1 Power Management" 2738 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2739 help 2740 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2741 2742config OLPC_XO1_RTC 2743 bool "OLPC XO-1 Real Time Clock" 2744 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2745 help 2746 Add support for the XO-1 real time clock, which can be used as a 2747 programmable wakeup source. 2748 2749config OLPC_XO1_SCI 2750 bool "OLPC XO-1 SCI extras" 2751 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2752 depends on INPUT=y 2753 select POWER_SUPPLY 2754 help 2755 Add support for SCI-based features of the OLPC XO-1 laptop: 2756 - EC-driven system wakeups 2757 - Power button 2758 - Ebook switch 2759 - Lid switch 2760 - AC adapter status updates 2761 - Battery status updates 2762 2763config OLPC_XO15_SCI 2764 bool "OLPC XO-1.5 SCI extras" 2765 depends on OLPC && ACPI 2766 select POWER_SUPPLY 2767 help 2768 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2769 - EC-driven system wakeups 2770 - AC adapter status updates 2771 - Battery status updates 2772 2773config ALIX 2774 bool "PCEngines ALIX System Support (LED setup)" 2775 select GPIOLIB 2776 help 2777 This option enables system support for the PCEngines ALIX. 2778 At present this just sets up LEDs for GPIO control on 2779 ALIX2/3/6 boards. However, other system specific setup should 2780 get added here. 2781 2782 Note: You must still enable the drivers for GPIO and LED support 2783 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2784 2785 Note: You have to set alix.force=1 for boards with Award BIOS. 2786 2787config NET5501 2788 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2789 select GPIOLIB 2790 help 2791 This option enables system support for the Soekris Engineering net5501. 2792 2793config GEOS 2794 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2795 select GPIOLIB 2796 depends on DMI 2797 help 2798 This option enables system support for the Traverse Technologies GEOS. 2799 2800config TS5500 2801 bool "Technologic Systems TS-5500 platform support" 2802 depends on MELAN 2803 select CHECK_SIGNATURE 2804 select NEW_LEDS 2805 select LEDS_CLASS 2806 help 2807 This option enables system support for the Technologic Systems TS-5500. 2808 2809endif # X86_32 2810 2811config AMD_NB 2812 def_bool y 2813 depends on CPU_SUP_AMD && PCI 2814 2815endmenu 2816 2817 2818menu "Binary Emulations" 2819 2820config IA32_EMULATION 2821 bool "IA32 Emulation" 2822 depends on X86_64 2823 select ARCH_WANT_OLD_COMPAT_IPC 2824 select BINFMT_ELF 2825 select COMPAT_OLD_SIGACTION 2826 help 2827 Include code to run legacy 32-bit programs under a 2828 64-bit kernel. You should likely turn this on, unless you're 2829 100% sure that you don't have any 32-bit programs left. 2830 2831config IA32_AOUT 2832 tristate "IA32 a.out support" 2833 depends on IA32_EMULATION 2834 depends on BROKEN 2835 help 2836 Support old a.out binaries in the 32bit emulation. 2837 2838config X86_X32 2839 bool "x32 ABI for 64-bit mode" 2840 depends on X86_64 2841 help 2842 Include code to run binaries for the x32 native 32-bit ABI 2843 for 64-bit processors. An x32 process gets access to the 2844 full 64-bit register file and wide data path while leaving 2845 pointers at 32 bits for smaller memory footprint. 2846 2847 You will need a recent binutils (2.22 or later) with 2848 elf32_x86_64 support enabled to compile a kernel with this 2849 option set. 2850 2851config COMPAT_32 2852 def_bool y 2853 depends on IA32_EMULATION || X86_32 2854 select HAVE_UID16 2855 select OLD_SIGSUSPEND3 2856 2857config COMPAT 2858 def_bool y 2859 depends on IA32_EMULATION || X86_X32 2860 2861if COMPAT 2862config COMPAT_FOR_U64_ALIGNMENT 2863 def_bool y 2864 2865config SYSVIPC_COMPAT 2866 def_bool y 2867 depends on SYSVIPC 2868endif 2869 2870endmenu 2871 2872 2873config HAVE_ATOMIC_IOMAP 2874 def_bool y 2875 depends on X86_32 2876 2877source "arch/x86/kvm/Kconfig" 2878 2879source "arch/x86/Kconfig.assembler" 2880