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