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_CURRENT_STACK_POINTER 73 select ARCH_HAS_DEBUG_VIRTUAL 74 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 75 select ARCH_HAS_DEVMEM_IS_ALLOWED 76 select ARCH_HAS_EARLY_DEBUG if KGDB 77 select ARCH_HAS_ELF_RANDOMIZE 78 select ARCH_HAS_FAST_MULTIPLIER 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_VM_GET_PAGE_PROT 98 select ARCH_HAS_DEBUG_WX 99 select ARCH_HAS_ZONE_DMA_SET if EXPERT 100 select ARCH_HAVE_NMI_SAFE_CMPXCHG 101 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 102 select ARCH_MIGHT_HAVE_PC_PARPORT 103 select ARCH_MIGHT_HAVE_PC_SERIO 104 select ARCH_STACKWALK 105 select ARCH_SUPPORTS_ACPI 106 select ARCH_SUPPORTS_ATOMIC_RMW 107 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 108 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 109 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 110 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 111 select ARCH_SUPPORTS_LTO_CLANG 112 select ARCH_SUPPORTS_LTO_CLANG_THIN 113 select ARCH_USE_BUILTIN_BSWAP 114 select ARCH_USE_MEMTEST 115 select ARCH_USE_QUEUED_RWLOCKS 116 select ARCH_USE_QUEUED_SPINLOCKS 117 select ARCH_USE_SYM_ANNOTATIONS 118 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 119 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 120 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 121 select ARCH_WANTS_NO_INSTR 122 select ARCH_WANT_GENERAL_HUGETLB 123 select ARCH_WANT_HUGE_PMD_SHARE 124 select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP if X86_64 125 select ARCH_WANT_LD_ORPHAN_WARN 126 select ARCH_WANTS_THP_SWAP if X86_64 127 select ARCH_HAS_PARANOID_L1D_FLUSH 128 select BUILDTIME_TABLE_SORT 129 select CLKEVT_I8253 130 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 131 select CLOCKSOURCE_WATCHDOG 132 select DCACHE_WORD_ACCESS 133 select DYNAMIC_SIGFRAME 134 select EDAC_ATOMIC_SCRUB 135 select EDAC_SUPPORT 136 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 137 select GENERIC_CLOCKEVENTS_MIN_ADJUST 138 select GENERIC_CMOS_UPDATE 139 select GENERIC_CPU_AUTOPROBE 140 select GENERIC_CPU_VULNERABILITIES 141 select GENERIC_EARLY_IOREMAP 142 select GENERIC_ENTRY 143 select GENERIC_IOMAP 144 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 145 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 146 select GENERIC_IRQ_MIGRATION if SMP 147 select GENERIC_IRQ_PROBE 148 select GENERIC_IRQ_RESERVATION_MODE 149 select GENERIC_IRQ_SHOW 150 select GENERIC_PENDING_IRQ if SMP 151 select GENERIC_PTDUMP 152 select GENERIC_SMP_IDLE_THREAD 153 select GENERIC_TIME_VSYSCALL 154 select GENERIC_GETTIMEOFDAY 155 select GENERIC_VDSO_TIME_NS 156 select GUP_GET_PTE_LOW_HIGH if X86_PAE 157 select HARDIRQS_SW_RESEND 158 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 159 select HAVE_ACPI_APEI if ACPI 160 select HAVE_ACPI_APEI_NMI if ACPI 161 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 162 select HAVE_ARCH_AUDITSYSCALL 163 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 164 select HAVE_ARCH_HUGE_VMALLOC if X86_64 165 select HAVE_ARCH_JUMP_LABEL 166 select HAVE_ARCH_JUMP_LABEL_RELATIVE 167 select HAVE_ARCH_KASAN if X86_64 168 select HAVE_ARCH_KASAN_VMALLOC if X86_64 169 select HAVE_ARCH_KFENCE 170 select HAVE_ARCH_KGDB 171 select HAVE_ARCH_MMAP_RND_BITS if MMU 172 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 173 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 174 select HAVE_ARCH_PREL32_RELOCATIONS 175 select HAVE_ARCH_SECCOMP_FILTER 176 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 177 select HAVE_ARCH_STACKLEAK 178 select HAVE_ARCH_TRACEHOOK 179 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 180 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 181 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 182 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 183 select HAVE_ARCH_VMAP_STACK if X86_64 184 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 185 select HAVE_ARCH_WITHIN_STACK_FRAMES 186 select HAVE_ASM_MODVERSIONS 187 select HAVE_CMPXCHG_DOUBLE 188 select HAVE_CMPXCHG_LOCAL 189 select HAVE_CONTEXT_TRACKING if X86_64 190 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING 191 select HAVE_C_RECORDMCOUNT 192 select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION 193 select HAVE_BUILDTIME_MCOUNT_SORT 194 select HAVE_DEBUG_KMEMLEAK 195 select HAVE_DMA_CONTIGUOUS 196 select HAVE_DYNAMIC_FTRACE 197 select HAVE_DYNAMIC_FTRACE_WITH_REGS 198 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 199 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 200 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 201 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 202 select HAVE_EBPF_JIT 203 select HAVE_EFFICIENT_UNALIGNED_ACCESS 204 select HAVE_EISA 205 select HAVE_EXIT_THREAD 206 select HAVE_FAST_GUP 207 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 208 select HAVE_FTRACE_MCOUNT_RECORD 209 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 210 select HAVE_FUNCTION_TRACER 211 select HAVE_GCC_PLUGINS 212 select HAVE_HW_BREAKPOINT 213 select HAVE_IOREMAP_PROT 214 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 215 select HAVE_IRQ_TIME_ACCOUNTING 216 select HAVE_KERNEL_BZIP2 217 select HAVE_KERNEL_GZIP 218 select HAVE_KERNEL_LZ4 219 select HAVE_KERNEL_LZMA 220 select HAVE_KERNEL_LZO 221 select HAVE_KERNEL_XZ 222 select HAVE_KERNEL_ZSTD 223 select HAVE_KPROBES 224 select HAVE_KPROBES_ON_FTRACE 225 select HAVE_FUNCTION_ERROR_INJECTION 226 select HAVE_KRETPROBES 227 select HAVE_RETHOOK 228 select HAVE_KVM 229 select HAVE_LIVEPATCH if X86_64 230 select HAVE_MIXED_BREAKPOINTS_REGS 231 select HAVE_MOD_ARCH_SPECIFIC 232 select HAVE_MOVE_PMD 233 select HAVE_MOVE_PUD 234 select HAVE_NMI 235 select HAVE_OPTPROBES 236 select HAVE_PCSPKR_PLATFORM 237 select HAVE_PERF_EVENTS 238 select HAVE_PERF_EVENTS_NMI 239 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 240 select HAVE_PCI 241 select HAVE_PERF_REGS 242 select HAVE_PERF_USER_STACK_DUMP 243 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 244 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 245 select HAVE_REGS_AND_STACK_ACCESS_API 246 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 247 select HAVE_FUNCTION_ARG_ACCESS_API 248 select HAVE_SETUP_PER_CPU_AREA 249 select HAVE_SOFTIRQ_ON_OWN_STACK 250 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 251 select HAVE_STACK_VALIDATION if X86_64 252 select HAVE_STATIC_CALL 253 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 254 select HAVE_PREEMPT_DYNAMIC_CALL 255 select HAVE_RSEQ 256 select HAVE_SYSCALL_TRACEPOINTS 257 select HAVE_UNSTABLE_SCHED_CLOCK 258 select HAVE_USER_RETURN_NOTIFIER 259 select HAVE_GENERIC_VDSO 260 select HOTPLUG_SMT if SMP 261 select IRQ_FORCED_THREADING 262 select NEED_PER_CPU_EMBED_FIRST_CHUNK 263 select NEED_PER_CPU_PAGE_FIRST_CHUNK 264 select NEED_SG_DMA_LENGTH 265 select PCI_DOMAINS if PCI 266 select PCI_LOCKLESS_CONFIG if PCI 267 select PERF_EVENTS 268 select RTC_LIB 269 select RTC_MC146818_LIB 270 select SPARSE_IRQ 271 select SRCU 272 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 273 select SYSCTL_EXCEPTION_TRACE 274 select THREAD_INFO_IN_TASK 275 select TRACE_IRQFLAGS_SUPPORT 276 select USER_STACKTRACE_SUPPORT 277 select VIRT_TO_BUS 278 select HAVE_ARCH_KCSAN if X86_64 279 select X86_FEATURE_NAMES if PROC_FS 280 select PROC_PID_ARCH_STATUS if PROC_FS 281 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 282 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 283 284config INSTRUCTION_DECODER 285 def_bool y 286 depends on KPROBES || PERF_EVENTS || UPROBES 287 288config OUTPUT_FORMAT 289 string 290 default "elf32-i386" if X86_32 291 default "elf64-x86-64" if X86_64 292 293config LOCKDEP_SUPPORT 294 def_bool y 295 296config STACKTRACE_SUPPORT 297 def_bool y 298 299config MMU 300 def_bool y 301 302config ARCH_MMAP_RND_BITS_MIN 303 default 28 if 64BIT 304 default 8 305 306config ARCH_MMAP_RND_BITS_MAX 307 default 32 if 64BIT 308 default 16 309 310config ARCH_MMAP_RND_COMPAT_BITS_MIN 311 default 8 312 313config ARCH_MMAP_RND_COMPAT_BITS_MAX 314 default 16 315 316config SBUS 317 bool 318 319config GENERIC_ISA_DMA 320 def_bool y 321 depends on ISA_DMA_API 322 323config GENERIC_BUG 324 def_bool y 325 depends on BUG 326 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 327 328config GENERIC_BUG_RELATIVE_POINTERS 329 bool 330 331config ARCH_MAY_HAVE_PC_FDC 332 def_bool y 333 depends on ISA_DMA_API 334 335config GENERIC_CALIBRATE_DELAY 336 def_bool y 337 338config ARCH_HAS_CPU_RELAX 339 def_bool y 340 341config ARCH_HIBERNATION_POSSIBLE 342 def_bool y 343 344config ARCH_NR_GPIO 345 int 346 default 1024 if X86_64 347 default 512 348 349config ARCH_SUSPEND_POSSIBLE 350 def_bool y 351 352config AUDIT_ARCH 353 def_bool y if X86_64 354 355config KASAN_SHADOW_OFFSET 356 hex 357 depends on KASAN 358 default 0xdffffc0000000000 359 360config HAVE_INTEL_TXT 361 def_bool y 362 depends on INTEL_IOMMU && ACPI 363 364config X86_32_SMP 365 def_bool y 366 depends on X86_32 && SMP 367 368config X86_64_SMP 369 def_bool y 370 depends on X86_64 && SMP 371 372config ARCH_SUPPORTS_UPROBES 373 def_bool y 374 375config FIX_EARLYCON_MEM 376 def_bool y 377 378config DYNAMIC_PHYSICAL_MASK 379 bool 380 381config PGTABLE_LEVELS 382 int 383 default 5 if X86_5LEVEL 384 default 4 if X86_64 385 default 3 if X86_PAE 386 default 2 387 388config CC_HAS_SANE_STACKPROTECTOR 389 bool 390 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 391 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 392 help 393 We have to make sure stack protector is unconditionally disabled if 394 the compiler produces broken code or if it does not let us control 395 the segment on 32-bit kernels. 396 397menu "Processor type and features" 398 399config SMP 400 bool "Symmetric multi-processing support" 401 help 402 This enables support for systems with more than one CPU. If you have 403 a system with only one CPU, say N. If you have a system with more 404 than one CPU, say Y. 405 406 If you say N here, the kernel will run on uni- and multiprocessor 407 machines, but will use only one CPU of a multiprocessor machine. If 408 you say Y here, the kernel will run on many, but not all, 409 uniprocessor machines. On a uniprocessor machine, the kernel 410 will run faster if you say N here. 411 412 Note that if you say Y here and choose architecture "586" or 413 "Pentium" under "Processor family", the kernel will not work on 486 414 architectures. Similarly, multiprocessor kernels for the "PPro" 415 architecture may not work on all Pentium based boards. 416 417 People using multiprocessor machines who say Y here should also say 418 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 419 Management" code will be disabled if you say Y here. 420 421 See also <file:Documentation/x86/i386/IO-APIC.rst>, 422 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 423 <http://www.tldp.org/docs.html#howto>. 424 425 If you don't know what to do here, say N. 426 427config X86_FEATURE_NAMES 428 bool "Processor feature human-readable names" if EMBEDDED 429 default y 430 help 431 This option compiles in a table of x86 feature bits and corresponding 432 names. This is required to support /proc/cpuinfo and a few kernel 433 messages. You can disable this to save space, at the expense of 434 making those few kernel messages show numeric feature bits instead. 435 436 If in doubt, say Y. 437 438config X86_X2APIC 439 bool "Support x2apic" 440 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 441 help 442 This enables x2apic support on CPUs that have this feature. 443 444 This allows 32-bit apic IDs (so it can support very large systems), 445 and accesses the local apic via MSRs not via mmio. 446 447 If you don't know what to do here, say N. 448 449config X86_MPPARSE 450 bool "Enable MPS table" if ACPI 451 default y 452 depends on X86_LOCAL_APIC 453 help 454 For old smp systems that do not have proper acpi support. Newer systems 455 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 456 457config GOLDFISH 458 def_bool y 459 depends on X86_GOLDFISH 460 461config RETPOLINE 462 bool "Avoid speculative indirect branches in kernel" 463 default y 464 help 465 Compile kernel with the retpoline compiler options to guard against 466 kernel-to-user data leaks by avoiding speculative indirect 467 branches. Requires a compiler with -mindirect-branch=thunk-extern 468 support for full protection. The kernel may run slower. 469 470config CC_HAS_SLS 471 def_bool $(cc-option,-mharden-sls=all) 472 473config SLS 474 bool "Mitigate Straight-Line-Speculation" 475 depends on CC_HAS_SLS && X86_64 476 default n 477 help 478 Compile the kernel with straight-line-speculation options to guard 479 against straight line speculation. The kernel image might be slightly 480 larger. 481 482config X86_CPU_RESCTRL 483 bool "x86 CPU resource control support" 484 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 485 select KERNFS 486 select PROC_CPU_RESCTRL if PROC_FS 487 help 488 Enable x86 CPU resource control support. 489 490 Provide support for the allocation and monitoring of system resources 491 usage by the CPU. 492 493 Intel calls this Intel Resource Director Technology 494 (Intel(R) RDT). More information about RDT can be found in the 495 Intel x86 Architecture Software Developer Manual. 496 497 AMD calls this AMD Platform Quality of Service (AMD QoS). 498 More information about AMD QoS can be found in the AMD64 Technology 499 Platform Quality of Service Extensions manual. 500 501 Say N if unsure. 502 503if X86_32 504config X86_BIGSMP 505 bool "Support for big SMP systems with more than 8 CPUs" 506 depends on SMP 507 help 508 This option is needed for the systems that have more than 8 CPUs. 509 510config X86_EXTENDED_PLATFORM 511 bool "Support for extended (non-PC) x86 platforms" 512 default y 513 help 514 If you disable this option then the kernel will only support 515 standard PC platforms. (which covers the vast majority of 516 systems out there.) 517 518 If you enable this option then you'll be able to select support 519 for the following (non-PC) 32 bit x86 platforms: 520 Goldfish (Android emulator) 521 AMD Elan 522 RDC R-321x SoC 523 SGI 320/540 (Visual Workstation) 524 STA2X11-based (e.g. Northville) 525 Moorestown MID devices 526 527 If you have one of these systems, or if you want to build a 528 generic distribution kernel, say Y here - otherwise say N. 529endif 530 531if X86_64 532config X86_EXTENDED_PLATFORM 533 bool "Support for extended (non-PC) x86 platforms" 534 default y 535 help 536 If you disable this option then the kernel will only support 537 standard PC platforms. (which covers the vast majority of 538 systems out there.) 539 540 If you enable this option then you'll be able to select support 541 for the following (non-PC) 64 bit x86 platforms: 542 Numascale NumaChip 543 ScaleMP vSMP 544 SGI Ultraviolet 545 546 If you have one of these systems, or if you want to build a 547 generic distribution kernel, say Y here - otherwise say N. 548endif 549# This is an alphabetically sorted list of 64 bit extended platforms 550# Please maintain the alphabetic order if and when there are additions 551config X86_NUMACHIP 552 bool "Numascale NumaChip" 553 depends on X86_64 554 depends on X86_EXTENDED_PLATFORM 555 depends on NUMA 556 depends on SMP 557 depends on X86_X2APIC 558 depends on PCI_MMCONFIG 559 help 560 Adds support for Numascale NumaChip large-SMP systems. Needed to 561 enable more than ~168 cores. 562 If you don't have one of these, you should say N here. 563 564config X86_VSMP 565 bool "ScaleMP vSMP" 566 select HYPERVISOR_GUEST 567 select PARAVIRT 568 depends on X86_64 && PCI 569 depends on X86_EXTENDED_PLATFORM 570 depends on SMP 571 help 572 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 573 supposed to run on these EM64T-based machines. Only choose this option 574 if you have one of these machines. 575 576config X86_UV 577 bool "SGI Ultraviolet" 578 depends on X86_64 579 depends on X86_EXTENDED_PLATFORM 580 depends on NUMA 581 depends on EFI 582 depends on KEXEC_CORE 583 depends on X86_X2APIC 584 depends on PCI 585 help 586 This option is needed in order to support SGI Ultraviolet systems. 587 If you don't have one of these, you should say N here. 588 589# Following is an alphabetically sorted list of 32 bit extended platforms 590# Please maintain the alphabetic order if and when there are additions 591 592config X86_GOLDFISH 593 bool "Goldfish (Virtual Platform)" 594 depends on X86_EXTENDED_PLATFORM 595 help 596 Enable support for the Goldfish virtual platform used primarily 597 for Android development. Unless you are building for the Android 598 Goldfish emulator say N here. 599 600config X86_INTEL_CE 601 bool "CE4100 TV platform" 602 depends on PCI 603 depends on PCI_GODIRECT 604 depends on X86_IO_APIC 605 depends on X86_32 606 depends on X86_EXTENDED_PLATFORM 607 select X86_REBOOTFIXUPS 608 select OF 609 select OF_EARLY_FLATTREE 610 help 611 Select for the Intel CE media processor (CE4100) SOC. 612 This option compiles in support for the CE4100 SOC for settop 613 boxes and media devices. 614 615config X86_INTEL_MID 616 bool "Intel MID platform support" 617 depends on X86_EXTENDED_PLATFORM 618 depends on X86_PLATFORM_DEVICES 619 depends on PCI 620 depends on X86_64 || (PCI_GOANY && X86_32) 621 depends on X86_IO_APIC 622 select I2C 623 select DW_APB_TIMER 624 select INTEL_SCU_PCI 625 help 626 Select to build a kernel capable of supporting Intel MID (Mobile 627 Internet Device) platform systems which do not have the PCI legacy 628 interfaces. If you are building for a PC class system say N here. 629 630 Intel MID platforms are based on an Intel processor and chipset which 631 consume less power than most of the x86 derivatives. 632 633config X86_INTEL_QUARK 634 bool "Intel Quark platform support" 635 depends on X86_32 636 depends on X86_EXTENDED_PLATFORM 637 depends on X86_PLATFORM_DEVICES 638 depends on X86_TSC 639 depends on PCI 640 depends on PCI_GOANY 641 depends on X86_IO_APIC 642 select IOSF_MBI 643 select INTEL_IMR 644 select COMMON_CLK 645 help 646 Select to include support for Quark X1000 SoC. 647 Say Y here if you have a Quark based system such as the Arduino 648 compatible Intel Galileo. 649 650config X86_INTEL_LPSS 651 bool "Intel Low Power Subsystem Support" 652 depends on X86 && ACPI && PCI 653 select COMMON_CLK 654 select PINCTRL 655 select IOSF_MBI 656 help 657 Select to build support for Intel Low Power Subsystem such as 658 found on Intel Lynxpoint PCH. Selecting this option enables 659 things like clock tree (common clock framework) and pincontrol 660 which are needed by the LPSS peripheral drivers. 661 662config X86_AMD_PLATFORM_DEVICE 663 bool "AMD ACPI2Platform devices support" 664 depends on ACPI 665 select COMMON_CLK 666 select PINCTRL 667 help 668 Select to interpret AMD specific ACPI device to platform device 669 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 670 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 671 implemented under PINCTRL subsystem. 672 673config IOSF_MBI 674 tristate "Intel SoC IOSF Sideband support for SoC platforms" 675 depends on PCI 676 help 677 This option enables sideband register access support for Intel SoC 678 platforms. On these platforms the IOSF sideband is used in lieu of 679 MSR's for some register accesses, mostly but not limited to thermal 680 and power. Drivers may query the availability of this device to 681 determine if they need the sideband in order to work on these 682 platforms. The sideband is available on the following SoC products. 683 This list is not meant to be exclusive. 684 - BayTrail 685 - Braswell 686 - Quark 687 688 You should say Y if you are running a kernel on one of these SoC's. 689 690config IOSF_MBI_DEBUG 691 bool "Enable IOSF sideband access through debugfs" 692 depends on IOSF_MBI && DEBUG_FS 693 help 694 Select this option to expose the IOSF sideband access registers (MCR, 695 MDR, MCRX) through debugfs to write and read register information from 696 different units on the SoC. This is most useful for obtaining device 697 state information for debug and analysis. As this is a general access 698 mechanism, users of this option would have specific knowledge of the 699 device they want to access. 700 701 If you don't require the option or are in doubt, say N. 702 703config X86_RDC321X 704 bool "RDC R-321x SoC" 705 depends on X86_32 706 depends on X86_EXTENDED_PLATFORM 707 select M486 708 select X86_REBOOTFIXUPS 709 help 710 This option is needed for RDC R-321x system-on-chip, also known 711 as R-8610-(G). 712 If you don't have one of these chips, you should say N here. 713 714config X86_32_NON_STANDARD 715 bool "Support non-standard 32-bit SMP architectures" 716 depends on X86_32 && SMP 717 depends on X86_EXTENDED_PLATFORM 718 help 719 This option compiles in the bigsmp and STA2X11 default 720 subarchitectures. It is intended for a generic binary 721 kernel. If you select them all, kernel will probe it one by 722 one and will fallback to default. 723 724# Alphabetically sorted list of Non standard 32 bit platforms 725 726config X86_SUPPORTS_MEMORY_FAILURE 727 def_bool y 728 # MCE code calls memory_failure(): 729 depends on X86_MCE 730 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 731 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 732 depends on X86_64 || !SPARSEMEM 733 select ARCH_SUPPORTS_MEMORY_FAILURE 734 735config STA2X11 736 bool "STA2X11 Companion Chip Support" 737 depends on X86_32_NON_STANDARD && PCI 738 select SWIOTLB 739 select MFD_STA2X11 740 select GPIOLIB 741 help 742 This adds support for boards based on the STA2X11 IO-Hub, 743 a.k.a. "ConneXt". The chip is used in place of the standard 744 PC chipset, so all "standard" peripherals are missing. If this 745 option is selected the kernel will still be able to boot on 746 standard PC machines. 747 748config X86_32_IRIS 749 tristate "Eurobraille/Iris poweroff module" 750 depends on X86_32 751 help 752 The Iris machines from EuroBraille do not have APM or ACPI support 753 to shut themselves down properly. A special I/O sequence is 754 needed to do so, which is what this module does at 755 kernel shutdown. 756 757 This is only for Iris machines from EuroBraille. 758 759 If unused, say N. 760 761config SCHED_OMIT_FRAME_POINTER 762 def_bool y 763 prompt "Single-depth WCHAN output" 764 depends on X86 765 help 766 Calculate simpler /proc/<PID>/wchan values. If this option 767 is disabled then wchan values will recurse back to the 768 caller function. This provides more accurate wchan values, 769 at the expense of slightly more scheduling overhead. 770 771 If in doubt, say "Y". 772 773menuconfig HYPERVISOR_GUEST 774 bool "Linux guest support" 775 help 776 Say Y here to enable options for running Linux under various hyper- 777 visors. This option enables basic hypervisor detection and platform 778 setup. 779 780 If you say N, all options in this submenu will be skipped and 781 disabled, and Linux guest support won't be built in. 782 783if HYPERVISOR_GUEST 784 785config PARAVIRT 786 bool "Enable paravirtualization code" 787 depends on HAVE_STATIC_CALL 788 help 789 This changes the kernel so it can modify itself when it is run 790 under a hypervisor, potentially improving performance significantly 791 over full virtualization. However, when run without a hypervisor 792 the kernel is theoretically slower and slightly larger. 793 794config PARAVIRT_XXL 795 bool 796 797config PARAVIRT_DEBUG 798 bool "paravirt-ops debugging" 799 depends on PARAVIRT && DEBUG_KERNEL 800 help 801 Enable to debug paravirt_ops internals. Specifically, BUG if 802 a paravirt_op is missing when it is called. 803 804config PARAVIRT_SPINLOCKS 805 bool "Paravirtualization layer for spinlocks" 806 depends on PARAVIRT && SMP 807 help 808 Paravirtualized spinlocks allow a pvops backend to replace the 809 spinlock implementation with something virtualization-friendly 810 (for example, block the virtual CPU rather than spinning). 811 812 It has a minimal impact on native kernels and gives a nice performance 813 benefit on paravirtualized KVM / Xen kernels. 814 815 If you are unsure how to answer this question, answer Y. 816 817config X86_HV_CALLBACK_VECTOR 818 def_bool n 819 820source "arch/x86/xen/Kconfig" 821 822config KVM_GUEST 823 bool "KVM Guest support (including kvmclock)" 824 depends on PARAVIRT 825 select PARAVIRT_CLOCK 826 select ARCH_CPUIDLE_HALTPOLL 827 select X86_HV_CALLBACK_VECTOR 828 default y 829 help 830 This option enables various optimizations for running under the KVM 831 hypervisor. It includes a paravirtualized clock, so that instead 832 of relying on a PIT (or probably other) emulation by the 833 underlying device model, the host provides the guest with 834 timing infrastructure such as time of day, and system time 835 836config ARCH_CPUIDLE_HALTPOLL 837 def_bool n 838 prompt "Disable host haltpoll when loading haltpoll driver" 839 help 840 If virtualized under KVM, disable host haltpoll. 841 842config PVH 843 bool "Support for running PVH guests" 844 help 845 This option enables the PVH entry point for guest virtual machines 846 as specified in the x86/HVM direct boot ABI. 847 848config PARAVIRT_TIME_ACCOUNTING 849 bool "Paravirtual steal time accounting" 850 depends on PARAVIRT 851 help 852 Select this option to enable fine granularity task steal time 853 accounting. Time spent executing other tasks in parallel with 854 the current vCPU is discounted from the vCPU power. To account for 855 that, there can be a small performance impact. 856 857 If in doubt, say N here. 858 859config PARAVIRT_CLOCK 860 bool 861 862config JAILHOUSE_GUEST 863 bool "Jailhouse non-root cell support" 864 depends on X86_64 && PCI 865 select X86_PM_TIMER 866 help 867 This option allows to run Linux as guest in a Jailhouse non-root 868 cell. You can leave this option disabled if you only want to start 869 Jailhouse and run Linux afterwards in the root cell. 870 871config ACRN_GUEST 872 bool "ACRN Guest support" 873 depends on X86_64 874 select X86_HV_CALLBACK_VECTOR 875 help 876 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 877 a flexible, lightweight reference open-source hypervisor, built with 878 real-time and safety-criticality in mind. It is built for embedded 879 IOT with small footprint and real-time features. More details can be 880 found in https://projectacrn.org/. 881 882endif #HYPERVISOR_GUEST 883 884source "arch/x86/Kconfig.cpu" 885 886config HPET_TIMER 887 def_bool X86_64 888 prompt "HPET Timer Support" if X86_32 889 help 890 Use the IA-PC HPET (High Precision Event Timer) to manage 891 time in preference to the PIT and RTC, if a HPET is 892 present. 893 HPET is the next generation timer replacing legacy 8254s. 894 The HPET provides a stable time base on SMP 895 systems, unlike the TSC, but it is more expensive to access, 896 as it is off-chip. The interface used is documented 897 in the HPET spec, revision 1. 898 899 You can safely choose Y here. However, HPET will only be 900 activated if the platform and the BIOS support this feature. 901 Otherwise the 8254 will be used for timing services. 902 903 Choose N to continue using the legacy 8254 timer. 904 905config HPET_EMULATE_RTC 906 def_bool y 907 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 908 909# Mark as expert because too many people got it wrong. 910# The code disables itself when not needed. 911config DMI 912 default y 913 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 914 bool "Enable DMI scanning" if EXPERT 915 help 916 Enabled scanning of DMI to identify machine quirks. Say Y 917 here unless you have verified that your setup is not 918 affected by entries in the DMI blacklist. Required by PNP 919 BIOS code. 920 921config GART_IOMMU 922 bool "Old AMD GART IOMMU support" 923 select DMA_OPS 924 select IOMMU_HELPER 925 select SWIOTLB 926 depends on X86_64 && PCI && AMD_NB 927 help 928 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 929 GART based hardware IOMMUs. 930 931 The GART supports full DMA access for devices with 32-bit access 932 limitations, on systems with more than 3 GB. This is usually needed 933 for USB, sound, many IDE/SATA chipsets and some other devices. 934 935 Newer systems typically have a modern AMD IOMMU, supported via 936 the CONFIG_AMD_IOMMU=y config option. 937 938 In normal configurations this driver is only active when needed: 939 there's more than 3 GB of memory and the system contains a 940 32-bit limited device. 941 942 If unsure, say Y. 943 944config MAXSMP 945 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 946 depends on X86_64 && SMP && DEBUG_KERNEL 947 select CPUMASK_OFFSTACK 948 help 949 Enable maximum number of CPUS and NUMA Nodes for this architecture. 950 If unsure, say N. 951 952# 953# The maximum number of CPUs supported: 954# 955# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 956# and which can be configured interactively in the 957# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 958# 959# The ranges are different on 32-bit and 64-bit kernels, depending on 960# hardware capabilities and scalability features of the kernel. 961# 962# ( If MAXSMP is enabled we just use the highest possible value and disable 963# interactive configuration. ) 964# 965 966config NR_CPUS_RANGE_BEGIN 967 int 968 default NR_CPUS_RANGE_END if MAXSMP 969 default 1 if !SMP 970 default 2 971 972config NR_CPUS_RANGE_END 973 int 974 depends on X86_32 975 default 64 if SMP && X86_BIGSMP 976 default 8 if SMP && !X86_BIGSMP 977 default 1 if !SMP 978 979config NR_CPUS_RANGE_END 980 int 981 depends on X86_64 982 default 8192 if SMP && CPUMASK_OFFSTACK 983 default 512 if SMP && !CPUMASK_OFFSTACK 984 default 1 if !SMP 985 986config NR_CPUS_DEFAULT 987 int 988 depends on X86_32 989 default 32 if X86_BIGSMP 990 default 8 if SMP 991 default 1 if !SMP 992 993config NR_CPUS_DEFAULT 994 int 995 depends on X86_64 996 default 8192 if MAXSMP 997 default 64 if SMP 998 default 1 if !SMP 999 1000config NR_CPUS 1001 int "Maximum number of CPUs" if SMP && !MAXSMP 1002 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1003 default NR_CPUS_DEFAULT 1004 help 1005 This allows you to specify the maximum number of CPUs which this 1006 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1007 supported value is 8192, otherwise the maximum value is 512. The 1008 minimum value which makes sense is 2. 1009 1010 This is purely to save memory: each supported CPU adds about 8KB 1011 to the kernel image. 1012 1013config SCHED_CLUSTER 1014 bool "Cluster scheduler support" 1015 depends on SMP 1016 default y 1017 help 1018 Cluster scheduler support improves the CPU scheduler's decision 1019 making when dealing with machines that have clusters of CPUs. 1020 Cluster usually means a couple of CPUs which are placed closely 1021 by sharing mid-level caches, last-level cache tags or internal 1022 busses. 1023 1024config SCHED_SMT 1025 def_bool y if SMP 1026 1027config SCHED_MC 1028 def_bool y 1029 prompt "Multi-core scheduler support" 1030 depends on SMP 1031 help 1032 Multi-core scheduler support improves the CPU scheduler's decision 1033 making when dealing with multi-core CPU chips at a cost of slightly 1034 increased overhead in some places. If unsure say N here. 1035 1036config SCHED_MC_PRIO 1037 bool "CPU core priorities scheduler support" 1038 depends on SCHED_MC && CPU_SUP_INTEL 1039 select X86_INTEL_PSTATE 1040 select CPU_FREQ 1041 default y 1042 help 1043 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1044 core ordering determined at manufacturing time, which allows 1045 certain cores to reach higher turbo frequencies (when running 1046 single threaded workloads) than others. 1047 1048 Enabling this kernel feature teaches the scheduler about 1049 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1050 scheduler's CPU selection logic accordingly, so that higher 1051 overall system performance can be achieved. 1052 1053 This feature will have no effect on CPUs without this feature. 1054 1055 If unsure say Y here. 1056 1057config UP_LATE_INIT 1058 def_bool y 1059 depends on !SMP && X86_LOCAL_APIC 1060 1061config X86_UP_APIC 1062 bool "Local APIC support on uniprocessors" if !PCI_MSI 1063 default PCI_MSI 1064 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1065 help 1066 A local APIC (Advanced Programmable Interrupt Controller) is an 1067 integrated interrupt controller in the CPU. If you have a single-CPU 1068 system which has a processor with a local APIC, you can say Y here to 1069 enable and use it. If you say Y here even though your machine doesn't 1070 have a local APIC, then the kernel will still run with no slowdown at 1071 all. The local APIC supports CPU-generated self-interrupts (timer, 1072 performance counters), and the NMI watchdog which detects hard 1073 lockups. 1074 1075config X86_UP_IOAPIC 1076 bool "IO-APIC support on uniprocessors" 1077 depends on X86_UP_APIC 1078 help 1079 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1080 SMP-capable replacement for PC-style interrupt controllers. Most 1081 SMP systems and many recent uniprocessor systems have one. 1082 1083 If you have a single-CPU system with an IO-APIC, you can say Y here 1084 to use it. If you say Y here even though your machine doesn't have 1085 an IO-APIC, then the kernel will still run with no slowdown at all. 1086 1087config X86_LOCAL_APIC 1088 def_bool y 1089 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1090 select IRQ_DOMAIN_HIERARCHY 1091 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1092 1093config X86_IO_APIC 1094 def_bool y 1095 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1096 1097config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1098 bool "Reroute for broken boot IRQs" 1099 depends on X86_IO_APIC 1100 help 1101 This option enables a workaround that fixes a source of 1102 spurious interrupts. This is recommended when threaded 1103 interrupt handling is used on systems where the generation of 1104 superfluous "boot interrupts" cannot be disabled. 1105 1106 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1107 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1108 kernel does during interrupt handling). On chipsets where this 1109 boot IRQ generation cannot be disabled, this workaround keeps 1110 the original IRQ line masked so that only the equivalent "boot 1111 IRQ" is delivered to the CPUs. The workaround also tells the 1112 kernel to set up the IRQ handler on the boot IRQ line. In this 1113 way only one interrupt is delivered to the kernel. Otherwise 1114 the spurious second interrupt may cause the kernel to bring 1115 down (vital) interrupt lines. 1116 1117 Only affects "broken" chipsets. Interrupt sharing may be 1118 increased on these systems. 1119 1120config X86_MCE 1121 bool "Machine Check / overheating reporting" 1122 select GENERIC_ALLOCATOR 1123 default y 1124 help 1125 Machine Check support allows the processor to notify the 1126 kernel if it detects a problem (e.g. overheating, data corruption). 1127 The action the kernel takes depends on the severity of the problem, 1128 ranging from warning messages to halting the machine. 1129 1130config X86_MCELOG_LEGACY 1131 bool "Support for deprecated /dev/mcelog character device" 1132 depends on X86_MCE 1133 help 1134 Enable support for /dev/mcelog which is needed by the old mcelog 1135 userspace logging daemon. Consider switching to the new generation 1136 rasdaemon solution. 1137 1138config X86_MCE_INTEL 1139 def_bool y 1140 prompt "Intel MCE features" 1141 depends on X86_MCE && X86_LOCAL_APIC 1142 help 1143 Additional support for intel specific MCE features such as 1144 the thermal monitor. 1145 1146config X86_MCE_AMD 1147 def_bool y 1148 prompt "AMD MCE features" 1149 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1150 help 1151 Additional support for AMD specific MCE features such as 1152 the DRAM Error Threshold. 1153 1154config X86_ANCIENT_MCE 1155 bool "Support for old Pentium 5 / WinChip machine checks" 1156 depends on X86_32 && X86_MCE 1157 help 1158 Include support for machine check handling on old Pentium 5 or WinChip 1159 systems. These typically need to be enabled explicitly on the command 1160 line. 1161 1162config X86_MCE_THRESHOLD 1163 depends on X86_MCE_AMD || X86_MCE_INTEL 1164 def_bool y 1165 1166config X86_MCE_INJECT 1167 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1168 tristate "Machine check injector support" 1169 help 1170 Provide support for injecting machine checks for testing purposes. 1171 If you don't know what a machine check is and you don't do kernel 1172 QA it is safe to say n. 1173 1174source "arch/x86/events/Kconfig" 1175 1176config X86_LEGACY_VM86 1177 bool "Legacy VM86 support" 1178 depends on X86_32 1179 help 1180 This option allows user programs to put the CPU into V8086 1181 mode, which is an 80286-era approximation of 16-bit real mode. 1182 1183 Some very old versions of X and/or vbetool require this option 1184 for user mode setting. Similarly, DOSEMU will use it if 1185 available to accelerate real mode DOS programs. However, any 1186 recent version of DOSEMU, X, or vbetool should be fully 1187 functional even without kernel VM86 support, as they will all 1188 fall back to software emulation. Nevertheless, if you are using 1189 a 16-bit DOS program where 16-bit performance matters, vm86 1190 mode might be faster than emulation and you might want to 1191 enable this option. 1192 1193 Note that any app that works on a 64-bit kernel is unlikely to 1194 need this option, as 64-bit kernels don't, and can't, support 1195 V8086 mode. This option is also unrelated to 16-bit protected 1196 mode and is not needed to run most 16-bit programs under Wine. 1197 1198 Enabling this option increases the complexity of the kernel 1199 and slows down exception handling a tiny bit. 1200 1201 If unsure, say N here. 1202 1203config VM86 1204 bool 1205 default X86_LEGACY_VM86 1206 1207config X86_16BIT 1208 bool "Enable support for 16-bit segments" if EXPERT 1209 default y 1210 depends on MODIFY_LDT_SYSCALL 1211 help 1212 This option is required by programs like Wine to run 16-bit 1213 protected mode legacy code on x86 processors. Disabling 1214 this option saves about 300 bytes on i386, or around 6K text 1215 plus 16K runtime memory on x86-64, 1216 1217config X86_ESPFIX32 1218 def_bool y 1219 depends on X86_16BIT && X86_32 1220 1221config X86_ESPFIX64 1222 def_bool y 1223 depends on X86_16BIT && X86_64 1224 1225config X86_VSYSCALL_EMULATION 1226 bool "Enable vsyscall emulation" if EXPERT 1227 default y 1228 depends on X86_64 1229 help 1230 This enables emulation of the legacy vsyscall page. Disabling 1231 it is roughly equivalent to booting with vsyscall=none, except 1232 that it will also disable the helpful warning if a program 1233 tries to use a vsyscall. With this option set to N, offending 1234 programs will just segfault, citing addresses of the form 1235 0xffffffffff600?00. 1236 1237 This option is required by many programs built before 2013, and 1238 care should be used even with newer programs if set to N. 1239 1240 Disabling this option saves about 7K of kernel size and 1241 possibly 4K of additional runtime pagetable memory. 1242 1243config X86_IOPL_IOPERM 1244 bool "IOPERM and IOPL Emulation" 1245 default y 1246 help 1247 This enables the ioperm() and iopl() syscalls which are necessary 1248 for legacy applications. 1249 1250 Legacy IOPL support is an overbroad mechanism which allows user 1251 space aside of accessing all 65536 I/O ports also to disable 1252 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1253 capabilities and permission from potentially active security 1254 modules. 1255 1256 The emulation restricts the functionality of the syscall to 1257 only allowing the full range I/O port access, but prevents the 1258 ability to disable interrupts from user space which would be 1259 granted if the hardware IOPL mechanism would be used. 1260 1261config TOSHIBA 1262 tristate "Toshiba Laptop support" 1263 depends on X86_32 1264 help 1265 This adds a driver to safely access the System Management Mode of 1266 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1267 not work on models with a Phoenix BIOS. The System Management Mode 1268 is used to set the BIOS and power saving options on Toshiba portables. 1269 1270 For information on utilities to make use of this driver see the 1271 Toshiba Linux utilities web site at: 1272 <http://www.buzzard.org.uk/toshiba/>. 1273 1274 Say Y if you intend to run this kernel on a Toshiba portable. 1275 Say N otherwise. 1276 1277config X86_REBOOTFIXUPS 1278 bool "Enable X86 board specific fixups for reboot" 1279 depends on X86_32 1280 help 1281 This enables chipset and/or board specific fixups to be done 1282 in order to get reboot to work correctly. This is only needed on 1283 some combinations of hardware and BIOS. The symptom, for which 1284 this config is intended, is when reboot ends with a stalled/hung 1285 system. 1286 1287 Currently, the only fixup is for the Geode machines using 1288 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1289 1290 Say Y if you want to enable the fixup. Currently, it's safe to 1291 enable this option even if you don't need it. 1292 Say N otherwise. 1293 1294config MICROCODE 1295 bool "CPU microcode loading support" 1296 default y 1297 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1298 help 1299 If you say Y here, you will be able to update the microcode on 1300 Intel and AMD processors. The Intel support is for the IA32 family, 1301 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1302 AMD support is for families 0x10 and later. You will obviously need 1303 the actual microcode binary data itself which is not shipped with 1304 the Linux kernel. 1305 1306 The preferred method to load microcode from a detached initrd is described 1307 in Documentation/x86/microcode.rst. For that you need to enable 1308 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1309 initrd for microcode blobs. 1310 1311 In addition, you can build the microcode into the kernel. For that you 1312 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1313 config option. 1314 1315config MICROCODE_INTEL 1316 bool "Intel microcode loading support" 1317 depends on MICROCODE 1318 default MICROCODE 1319 help 1320 This options enables microcode patch loading support for Intel 1321 processors. 1322 1323 For the current Intel microcode data package go to 1324 <https://downloadcenter.intel.com> and search for 1325 'Linux Processor Microcode Data File'. 1326 1327config MICROCODE_AMD 1328 bool "AMD microcode loading support" 1329 depends on MICROCODE 1330 help 1331 If you select this option, microcode patch loading support for AMD 1332 processors will be enabled. 1333 1334config MICROCODE_OLD_INTERFACE 1335 bool "Ancient loading interface (DEPRECATED)" 1336 default n 1337 depends on MICROCODE 1338 help 1339 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1340 which was used by userspace tools like iucode_tool and microcode.ctl. 1341 It is inadequate because it runs too late to be able to properly 1342 load microcode on a machine and it needs special tools. Instead, you 1343 should've switched to the early loading method with the initrd or 1344 builtin microcode by now: Documentation/x86/microcode.rst 1345 1346config X86_MSR 1347 tristate "/dev/cpu/*/msr - Model-specific register support" 1348 help 1349 This device gives privileged processes access to the x86 1350 Model-Specific Registers (MSRs). It is a character device with 1351 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1352 MSR accesses are directed to a specific CPU on multi-processor 1353 systems. 1354 1355config X86_CPUID 1356 tristate "/dev/cpu/*/cpuid - CPU information support" 1357 help 1358 This device gives processes access to the x86 CPUID instruction to 1359 be executed on a specific processor. It is a character device 1360 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1361 /dev/cpu/31/cpuid. 1362 1363choice 1364 prompt "High Memory Support" 1365 default HIGHMEM4G 1366 depends on X86_32 1367 1368config NOHIGHMEM 1369 bool "off" 1370 help 1371 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1372 However, the address space of 32-bit x86 processors is only 4 1373 Gigabytes large. That means that, if you have a large amount of 1374 physical memory, not all of it can be "permanently mapped" by the 1375 kernel. The physical memory that's not permanently mapped is called 1376 "high memory". 1377 1378 If you are compiling a kernel which will never run on a machine with 1379 more than 1 Gigabyte total physical RAM, answer "off" here (default 1380 choice and suitable for most users). This will result in a "3GB/1GB" 1381 split: 3GB are mapped so that each process sees a 3GB virtual memory 1382 space and the remaining part of the 4GB virtual memory space is used 1383 by the kernel to permanently map as much physical memory as 1384 possible. 1385 1386 If the machine has between 1 and 4 Gigabytes physical RAM, then 1387 answer "4GB" here. 1388 1389 If more than 4 Gigabytes is used then answer "64GB" here. This 1390 selection turns Intel PAE (Physical Address Extension) mode on. 1391 PAE implements 3-level paging on IA32 processors. PAE is fully 1392 supported by Linux, PAE mode is implemented on all recent Intel 1393 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1394 then the kernel will not boot on CPUs that don't support PAE! 1395 1396 The actual amount of total physical memory will either be 1397 auto detected or can be forced by using a kernel command line option 1398 such as "mem=256M". (Try "man bootparam" or see the documentation of 1399 your boot loader (lilo or loadlin) about how to pass options to the 1400 kernel at boot time.) 1401 1402 If unsure, say "off". 1403 1404config HIGHMEM4G 1405 bool "4GB" 1406 help 1407 Select this if you have a 32-bit processor and between 1 and 4 1408 gigabytes of physical RAM. 1409 1410config HIGHMEM64G 1411 bool "64GB" 1412 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1413 select X86_PAE 1414 help 1415 Select this if you have a 32-bit processor and more than 4 1416 gigabytes of physical RAM. 1417 1418endchoice 1419 1420choice 1421 prompt "Memory split" if EXPERT 1422 default VMSPLIT_3G 1423 depends on X86_32 1424 help 1425 Select the desired split between kernel and user memory. 1426 1427 If the address range available to the kernel is less than the 1428 physical memory installed, the remaining memory will be available 1429 as "high memory". Accessing high memory is a little more costly 1430 than low memory, as it needs to be mapped into the kernel first. 1431 Note that increasing the kernel address space limits the range 1432 available to user programs, making the address space there 1433 tighter. Selecting anything other than the default 3G/1G split 1434 will also likely make your kernel incompatible with binary-only 1435 kernel modules. 1436 1437 If you are not absolutely sure what you are doing, leave this 1438 option alone! 1439 1440 config VMSPLIT_3G 1441 bool "3G/1G user/kernel split" 1442 config VMSPLIT_3G_OPT 1443 depends on !X86_PAE 1444 bool "3G/1G user/kernel split (for full 1G low memory)" 1445 config VMSPLIT_2G 1446 bool "2G/2G user/kernel split" 1447 config VMSPLIT_2G_OPT 1448 depends on !X86_PAE 1449 bool "2G/2G user/kernel split (for full 2G low memory)" 1450 config VMSPLIT_1G 1451 bool "1G/3G user/kernel split" 1452endchoice 1453 1454config PAGE_OFFSET 1455 hex 1456 default 0xB0000000 if VMSPLIT_3G_OPT 1457 default 0x80000000 if VMSPLIT_2G 1458 default 0x78000000 if VMSPLIT_2G_OPT 1459 default 0x40000000 if VMSPLIT_1G 1460 default 0xC0000000 1461 depends on X86_32 1462 1463config HIGHMEM 1464 def_bool y 1465 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1466 1467config X86_PAE 1468 bool "PAE (Physical Address Extension) Support" 1469 depends on X86_32 && !HIGHMEM4G 1470 select PHYS_ADDR_T_64BIT 1471 select SWIOTLB 1472 help 1473 PAE is required for NX support, and furthermore enables 1474 larger swapspace support for non-overcommit purposes. It 1475 has the cost of more pagetable lookup overhead, and also 1476 consumes more pagetable space per process. 1477 1478config X86_5LEVEL 1479 bool "Enable 5-level page tables support" 1480 default y 1481 select DYNAMIC_MEMORY_LAYOUT 1482 select SPARSEMEM_VMEMMAP 1483 depends on X86_64 1484 help 1485 5-level paging enables access to larger address space: 1486 upto 128 PiB of virtual address space and 4 PiB of 1487 physical address space. 1488 1489 It will be supported by future Intel CPUs. 1490 1491 A kernel with the option enabled can be booted on machines that 1492 support 4- or 5-level paging. 1493 1494 See Documentation/x86/x86_64/5level-paging.rst for more 1495 information. 1496 1497 Say N if unsure. 1498 1499config X86_DIRECT_GBPAGES 1500 def_bool y 1501 depends on X86_64 1502 help 1503 Certain kernel features effectively disable kernel 1504 linear 1 GB mappings (even if the CPU otherwise 1505 supports them), so don't confuse the user by printing 1506 that we have them enabled. 1507 1508config X86_CPA_STATISTICS 1509 bool "Enable statistic for Change Page Attribute" 1510 depends on DEBUG_FS 1511 help 1512 Expose statistics about the Change Page Attribute mechanism, which 1513 helps to determine the effectiveness of preserving large and huge 1514 page mappings when mapping protections are changed. 1515 1516config X86_MEM_ENCRYPT 1517 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1518 select DYNAMIC_PHYSICAL_MASK 1519 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 1520 def_bool n 1521 1522config AMD_MEM_ENCRYPT 1523 bool "AMD Secure Memory Encryption (SME) support" 1524 depends on X86_64 && CPU_SUP_AMD 1525 select DMA_COHERENT_POOL 1526 select ARCH_USE_MEMREMAP_PROT 1527 select INSTRUCTION_DECODER 1528 select ARCH_HAS_CC_PLATFORM 1529 select X86_MEM_ENCRYPT 1530 help 1531 Say yes to enable support for the encryption of system memory. 1532 This requires an AMD processor that supports Secure Memory 1533 Encryption (SME). 1534 1535config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1536 bool "Activate AMD Secure Memory Encryption (SME) by default" 1537 depends on AMD_MEM_ENCRYPT 1538 help 1539 Say yes to have system memory encrypted by default if running on 1540 an AMD processor that supports Secure Memory Encryption (SME). 1541 1542 If set to Y, then the encryption of system memory can be 1543 deactivated with the mem_encrypt=off command line option. 1544 1545 If set to N, then the encryption of system memory can be 1546 activated with the mem_encrypt=on command line option. 1547 1548# Common NUMA Features 1549config NUMA 1550 bool "NUMA Memory Allocation and Scheduler Support" 1551 depends on SMP 1552 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1553 default y if X86_BIGSMP 1554 select USE_PERCPU_NUMA_NODE_ID 1555 help 1556 Enable NUMA (Non-Uniform Memory Access) support. 1557 1558 The kernel will try to allocate memory used by a CPU on the 1559 local memory controller of the CPU and add some more 1560 NUMA awareness to the kernel. 1561 1562 For 64-bit this is recommended if the system is Intel Core i7 1563 (or later), AMD Opteron, or EM64T NUMA. 1564 1565 For 32-bit this is only needed if you boot a 32-bit 1566 kernel on a 64-bit NUMA platform. 1567 1568 Otherwise, you should say N. 1569 1570config AMD_NUMA 1571 def_bool y 1572 prompt "Old style AMD Opteron NUMA detection" 1573 depends on X86_64 && NUMA && PCI 1574 help 1575 Enable AMD NUMA node topology detection. You should say Y here if 1576 you have a multi processor AMD system. This uses an old method to 1577 read the NUMA configuration directly from the builtin Northbridge 1578 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1579 which also takes priority if both are compiled in. 1580 1581config X86_64_ACPI_NUMA 1582 def_bool y 1583 prompt "ACPI NUMA detection" 1584 depends on X86_64 && NUMA && ACPI && PCI 1585 select ACPI_NUMA 1586 help 1587 Enable ACPI SRAT based node topology detection. 1588 1589config NUMA_EMU 1590 bool "NUMA emulation" 1591 depends on NUMA 1592 help 1593 Enable NUMA emulation. A flat machine will be split 1594 into virtual nodes when booted with "numa=fake=N", where N is the 1595 number of nodes. This is only useful for debugging. 1596 1597config NODES_SHIFT 1598 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1599 range 1 10 1600 default "10" if MAXSMP 1601 default "6" if X86_64 1602 default "3" 1603 depends on NUMA 1604 help 1605 Specify the maximum number of NUMA Nodes available on the target 1606 system. Increases memory reserved to accommodate various tables. 1607 1608config ARCH_FLATMEM_ENABLE 1609 def_bool y 1610 depends on X86_32 && !NUMA 1611 1612config ARCH_SPARSEMEM_ENABLE 1613 def_bool y 1614 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1615 select SPARSEMEM_STATIC if X86_32 1616 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1617 1618config ARCH_SPARSEMEM_DEFAULT 1619 def_bool X86_64 || (NUMA && X86_32) 1620 1621config ARCH_SELECT_MEMORY_MODEL 1622 def_bool y 1623 depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1624 1625config ARCH_MEMORY_PROBE 1626 bool "Enable sysfs memory/probe interface" 1627 depends on MEMORY_HOTPLUG 1628 help 1629 This option enables a sysfs memory/probe interface for testing. 1630 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1631 If you are unsure how to answer this question, answer N. 1632 1633config ARCH_PROC_KCORE_TEXT 1634 def_bool y 1635 depends on X86_64 && PROC_KCORE 1636 1637config ILLEGAL_POINTER_VALUE 1638 hex 1639 default 0 if X86_32 1640 default 0xdead000000000000 if X86_64 1641 1642config X86_PMEM_LEGACY_DEVICE 1643 bool 1644 1645config X86_PMEM_LEGACY 1646 tristate "Support non-standard NVDIMMs and ADR protected memory" 1647 depends on PHYS_ADDR_T_64BIT 1648 depends on BLK_DEV 1649 select X86_PMEM_LEGACY_DEVICE 1650 select NUMA_KEEP_MEMINFO if NUMA 1651 select LIBNVDIMM 1652 help 1653 Treat memory marked using the non-standard e820 type of 12 as used 1654 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1655 The kernel will offer these regions to the 'pmem' driver so 1656 they can be used for persistent storage. 1657 1658 Say Y if unsure. 1659 1660config HIGHPTE 1661 bool "Allocate 3rd-level pagetables from highmem" 1662 depends on HIGHMEM 1663 help 1664 The VM uses one page table entry for each page of physical memory. 1665 For systems with a lot of RAM, this can be wasteful of precious 1666 low memory. Setting this option will put user-space page table 1667 entries in high memory. 1668 1669config X86_CHECK_BIOS_CORRUPTION 1670 bool "Check for low memory corruption" 1671 help 1672 Periodically check for memory corruption in low memory, which 1673 is suspected to be caused by BIOS. Even when enabled in the 1674 configuration, it is disabled at runtime. Enable it by 1675 setting "memory_corruption_check=1" on the kernel command 1676 line. By default it scans the low 64k of memory every 60 1677 seconds; see the memory_corruption_check_size and 1678 memory_corruption_check_period parameters in 1679 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1680 1681 When enabled with the default parameters, this option has 1682 almost no overhead, as it reserves a relatively small amount 1683 of memory and scans it infrequently. It both detects corruption 1684 and prevents it from affecting the running system. 1685 1686 It is, however, intended as a diagnostic tool; if repeatable 1687 BIOS-originated corruption always affects the same memory, 1688 you can use memmap= to prevent the kernel from using that 1689 memory. 1690 1691config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1692 bool "Set the default setting of memory_corruption_check" 1693 depends on X86_CHECK_BIOS_CORRUPTION 1694 default y 1695 help 1696 Set whether the default state of memory_corruption_check is 1697 on or off. 1698 1699config MATH_EMULATION 1700 bool 1701 depends on MODIFY_LDT_SYSCALL 1702 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1703 help 1704 Linux can emulate a math coprocessor (used for floating point 1705 operations) if you don't have one. 486DX and Pentium processors have 1706 a math coprocessor built in, 486SX and 386 do not, unless you added 1707 a 487DX or 387, respectively. (The messages during boot time can 1708 give you some hints here ["man dmesg"].) Everyone needs either a 1709 coprocessor or this emulation. 1710 1711 If you don't have a math coprocessor, you need to say Y here; if you 1712 say Y here even though you have a coprocessor, the coprocessor will 1713 be used nevertheless. (This behavior can be changed with the kernel 1714 command line option "no387", which comes handy if your coprocessor 1715 is broken. Try "man bootparam" or see the documentation of your boot 1716 loader (lilo or loadlin) about how to pass options to the kernel at 1717 boot time.) This means that it is a good idea to say Y here if you 1718 intend to use this kernel on different machines. 1719 1720 More information about the internals of the Linux math coprocessor 1721 emulation can be found in <file:arch/x86/math-emu/README>. 1722 1723 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1724 kernel, it won't hurt. 1725 1726config MTRR 1727 def_bool y 1728 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1729 help 1730 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1731 the Memory Type Range Registers (MTRRs) may be used to control 1732 processor access to memory ranges. This is most useful if you have 1733 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1734 allows bus write transfers to be combined into a larger transfer 1735 before bursting over the PCI/AGP bus. This can increase performance 1736 of image write operations 2.5 times or more. Saying Y here creates a 1737 /proc/mtrr file which may be used to manipulate your processor's 1738 MTRRs. Typically the X server should use this. 1739 1740 This code has a reasonably generic interface so that similar 1741 control registers on other processors can be easily supported 1742 as well: 1743 1744 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1745 Registers (ARRs) which provide a similar functionality to MTRRs. For 1746 these, the ARRs are used to emulate the MTRRs. 1747 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1748 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1749 write-combining. All of these processors are supported by this code 1750 and it makes sense to say Y here if you have one of them. 1751 1752 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1753 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1754 can lead to all sorts of problems, so it's good to say Y here. 1755 1756 You can safely say Y even if your machine doesn't have MTRRs, you'll 1757 just add about 9 KB to your kernel. 1758 1759 See <file:Documentation/x86/mtrr.rst> for more information. 1760 1761config MTRR_SANITIZER 1762 def_bool y 1763 prompt "MTRR cleanup support" 1764 depends on MTRR 1765 help 1766 Convert MTRR layout from continuous to discrete, so X drivers can 1767 add writeback entries. 1768 1769 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1770 The largest mtrr entry size for a continuous block can be set with 1771 mtrr_chunk_size. 1772 1773 If unsure, say Y. 1774 1775config MTRR_SANITIZER_ENABLE_DEFAULT 1776 int "MTRR cleanup enable value (0-1)" 1777 range 0 1 1778 default "0" 1779 depends on MTRR_SANITIZER 1780 help 1781 Enable mtrr cleanup default value 1782 1783config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1784 int "MTRR cleanup spare reg num (0-7)" 1785 range 0 7 1786 default "1" 1787 depends on MTRR_SANITIZER 1788 help 1789 mtrr cleanup spare entries default, it can be changed via 1790 mtrr_spare_reg_nr=N on the kernel command line. 1791 1792config X86_PAT 1793 def_bool y 1794 prompt "x86 PAT support" if EXPERT 1795 depends on MTRR 1796 help 1797 Use PAT attributes to setup page level cache control. 1798 1799 PATs are the modern equivalents of MTRRs and are much more 1800 flexible than MTRRs. 1801 1802 Say N here if you see bootup problems (boot crash, boot hang, 1803 spontaneous reboots) or a non-working video driver. 1804 1805 If unsure, say Y. 1806 1807config ARCH_USES_PG_UNCACHED 1808 def_bool y 1809 depends on X86_PAT 1810 1811config ARCH_RANDOM 1812 def_bool y 1813 prompt "x86 architectural random number generator" if EXPERT 1814 help 1815 Enable the x86 architectural RDRAND instruction 1816 (Intel Bull Mountain technology) to generate random numbers. 1817 If supported, this is a high bandwidth, cryptographically 1818 secure hardware random number generator. 1819 1820config X86_SMAP 1821 def_bool y 1822 prompt "Supervisor Mode Access Prevention" if EXPERT 1823 help 1824 Supervisor Mode Access Prevention (SMAP) is a security 1825 feature in newer Intel processors. There is a small 1826 performance cost if this enabled and turned on; there is 1827 also a small increase in the kernel size if this is enabled. 1828 1829 If unsure, say Y. 1830 1831config X86_UMIP 1832 def_bool y 1833 prompt "User Mode Instruction Prevention" if EXPERT 1834 help 1835 User Mode Instruction Prevention (UMIP) is a security feature in 1836 some x86 processors. If enabled, a general protection fault is 1837 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1838 executed in user mode. These instructions unnecessarily expose 1839 information about the hardware state. 1840 1841 The vast majority of applications do not use these instructions. 1842 For the very few that do, software emulation is provided in 1843 specific cases in protected and virtual-8086 modes. Emulated 1844 results are dummy. 1845 1846config CC_HAS_IBT 1847 # GCC >= 9 and binutils >= 2.29 1848 # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1849 # Clang/LLVM >= 14 1850 # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1851 # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1852 def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1853 (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1854 $(as-instr,endbr64) 1855 1856config X86_KERNEL_IBT 1857 prompt "Indirect Branch Tracking" 1858 bool 1859 depends on X86_64 && CC_HAS_IBT && STACK_VALIDATION 1860 # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1861 depends on !LD_IS_LLD || LLD_VERSION >= 140000 1862 help 1863 Build the kernel with support for Indirect Branch Tracking, a 1864 hardware support course-grain forward-edge Control Flow Integrity 1865 protection. It enforces that all indirect calls must land on 1866 an ENDBR instruction, as such, the compiler will instrument the 1867 code with them to make this happen. 1868 1869 In addition to building the kernel with IBT, seal all functions that 1870 are not indirect call targets, avoiding them ever becomming one. 1871 1872 This requires LTO like objtool runs and will slow down the build. It 1873 does significantly reduce the number of ENDBR instructions in the 1874 kernel image. 1875 1876config X86_INTEL_MEMORY_PROTECTION_KEYS 1877 prompt "Memory Protection Keys" 1878 def_bool y 1879 # Note: only available in 64-bit mode 1880 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1881 select ARCH_USES_HIGH_VMA_FLAGS 1882 select ARCH_HAS_PKEYS 1883 help 1884 Memory Protection Keys provides a mechanism for enforcing 1885 page-based protections, but without requiring modification of the 1886 page tables when an application changes protection domains. 1887 1888 For details, see Documentation/core-api/protection-keys.rst 1889 1890 If unsure, say y. 1891 1892choice 1893 prompt "TSX enable mode" 1894 depends on CPU_SUP_INTEL 1895 default X86_INTEL_TSX_MODE_OFF 1896 help 1897 Intel's TSX (Transactional Synchronization Extensions) feature 1898 allows to optimize locking protocols through lock elision which 1899 can lead to a noticeable performance boost. 1900 1901 On the other hand it has been shown that TSX can be exploited 1902 to form side channel attacks (e.g. TAA) and chances are there 1903 will be more of those attacks discovered in the future. 1904 1905 Therefore TSX is not enabled by default (aka tsx=off). An admin 1906 might override this decision by tsx=on the command line parameter. 1907 Even with TSX enabled, the kernel will attempt to enable the best 1908 possible TAA mitigation setting depending on the microcode available 1909 for the particular machine. 1910 1911 This option allows to set the default tsx mode between tsx=on, =off 1912 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1913 details. 1914 1915 Say off if not sure, auto if TSX is in use but it should be used on safe 1916 platforms or on if TSX is in use and the security aspect of tsx is not 1917 relevant. 1918 1919config X86_INTEL_TSX_MODE_OFF 1920 bool "off" 1921 help 1922 TSX is disabled if possible - equals to tsx=off command line parameter. 1923 1924config X86_INTEL_TSX_MODE_ON 1925 bool "on" 1926 help 1927 TSX is always enabled on TSX capable HW - equals the tsx=on command 1928 line parameter. 1929 1930config X86_INTEL_TSX_MODE_AUTO 1931 bool "auto" 1932 help 1933 TSX is enabled on TSX capable HW that is believed to be safe against 1934 side channel attacks- equals the tsx=auto command line parameter. 1935endchoice 1936 1937config X86_SGX 1938 bool "Software Guard eXtensions (SGX)" 1939 depends on X86_64 && CPU_SUP_INTEL 1940 depends on CRYPTO=y 1941 depends on CRYPTO_SHA256=y 1942 select SRCU 1943 select MMU_NOTIFIER 1944 select NUMA_KEEP_MEMINFO if NUMA 1945 select XARRAY_MULTI 1946 help 1947 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1948 that can be used by applications to set aside private regions of code 1949 and data, referred to as enclaves. An enclave's private memory can 1950 only be accessed by code running within the enclave. Accesses from 1951 outside the enclave, including other enclaves, are disallowed by 1952 hardware. 1953 1954 If unsure, say N. 1955 1956config EFI 1957 bool "EFI runtime service support" 1958 depends on ACPI 1959 select UCS2_STRING 1960 select EFI_RUNTIME_WRAPPERS 1961 select ARCH_USE_MEMREMAP_PROT 1962 help 1963 This enables the kernel to use EFI runtime services that are 1964 available (such as the EFI variable services). 1965 1966 This option is only useful on systems that have EFI firmware. 1967 In addition, you should use the latest ELILO loader available 1968 at <http://elilo.sourceforge.net> in order to take advantage 1969 of EFI runtime services. However, even with this option, the 1970 resultant kernel should continue to boot on existing non-EFI 1971 platforms. 1972 1973config EFI_STUB 1974 bool "EFI stub support" 1975 depends on EFI 1976 depends on $(cc-option,-mabi=ms) || X86_32 1977 select RELOCATABLE 1978 help 1979 This kernel feature allows a bzImage to be loaded directly 1980 by EFI firmware without the use of a bootloader. 1981 1982 See Documentation/admin-guide/efi-stub.rst for more information. 1983 1984config EFI_MIXED 1985 bool "EFI mixed-mode support" 1986 depends on EFI_STUB && X86_64 1987 help 1988 Enabling this feature allows a 64-bit kernel to be booted 1989 on a 32-bit firmware, provided that your CPU supports 64-bit 1990 mode. 1991 1992 Note that it is not possible to boot a mixed-mode enabled 1993 kernel via the EFI boot stub - a bootloader that supports 1994 the EFI handover protocol must be used. 1995 1996 If unsure, say N. 1997 1998source "kernel/Kconfig.hz" 1999 2000config KEXEC 2001 bool "kexec system call" 2002 select KEXEC_CORE 2003 help 2004 kexec is a system call that implements the ability to shutdown your 2005 current kernel, and to start another kernel. It is like a reboot 2006 but it is independent of the system firmware. And like a reboot 2007 you can start any kernel with it, not just Linux. 2008 2009 The name comes from the similarity to the exec system call. 2010 2011 It is an ongoing process to be certain the hardware in a machine 2012 is properly shutdown, so do not be surprised if this code does not 2013 initially work for you. As of this writing the exact hardware 2014 interface is strongly in flux, so no good recommendation can be 2015 made. 2016 2017config KEXEC_FILE 2018 bool "kexec file based system call" 2019 select KEXEC_CORE 2020 select BUILD_BIN2C 2021 depends on X86_64 2022 depends on CRYPTO=y 2023 depends on CRYPTO_SHA256=y 2024 help 2025 This is new version of kexec system call. This system call is 2026 file based and takes file descriptors as system call argument 2027 for kernel and initramfs as opposed to list of segments as 2028 accepted by previous system call. 2029 2030config ARCH_HAS_KEXEC_PURGATORY 2031 def_bool KEXEC_FILE 2032 2033config KEXEC_SIG 2034 bool "Verify kernel signature during kexec_file_load() syscall" 2035 depends on KEXEC_FILE 2036 help 2037 2038 This option makes the kexec_file_load() syscall check for a valid 2039 signature of the kernel image. The image can still be loaded without 2040 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2041 there's a signature that we can check, then it must be valid. 2042 2043 In addition to this option, you need to enable signature 2044 verification for the corresponding kernel image type being 2045 loaded in order for this to work. 2046 2047config KEXEC_SIG_FORCE 2048 bool "Require a valid signature in kexec_file_load() syscall" 2049 depends on KEXEC_SIG 2050 help 2051 This option makes kernel signature verification mandatory for 2052 the kexec_file_load() syscall. 2053 2054config KEXEC_BZIMAGE_VERIFY_SIG 2055 bool "Enable bzImage signature verification support" 2056 depends on KEXEC_SIG 2057 depends on SIGNED_PE_FILE_VERIFICATION 2058 select SYSTEM_TRUSTED_KEYRING 2059 help 2060 Enable bzImage signature verification support. 2061 2062config CRASH_DUMP 2063 bool "kernel crash dumps" 2064 depends on X86_64 || (X86_32 && HIGHMEM) 2065 help 2066 Generate crash dump after being started by kexec. 2067 This should be normally only set in special crash dump kernels 2068 which are loaded in the main kernel with kexec-tools into 2069 a specially reserved region and then later executed after 2070 a crash by kdump/kexec. The crash dump kernel must be compiled 2071 to a memory address not used by the main kernel or BIOS using 2072 PHYSICAL_START, or it must be built as a relocatable image 2073 (CONFIG_RELOCATABLE=y). 2074 For more details see Documentation/admin-guide/kdump/kdump.rst 2075 2076config KEXEC_JUMP 2077 bool "kexec jump" 2078 depends on KEXEC && HIBERNATION 2079 help 2080 Jump between original kernel and kexeced kernel and invoke 2081 code in physical address mode via KEXEC 2082 2083config PHYSICAL_START 2084 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2085 default "0x1000000" 2086 help 2087 This gives the physical address where the kernel is loaded. 2088 2089 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2090 bzImage will decompress itself to above physical address and 2091 run from there. Otherwise, bzImage will run from the address where 2092 it has been loaded by the boot loader and will ignore above physical 2093 address. 2094 2095 In normal kdump cases one does not have to set/change this option 2096 as now bzImage can be compiled as a completely relocatable image 2097 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2098 address. This option is mainly useful for the folks who don't want 2099 to use a bzImage for capturing the crash dump and want to use a 2100 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2101 to be specifically compiled to run from a specific memory area 2102 (normally a reserved region) and this option comes handy. 2103 2104 So if you are using bzImage for capturing the crash dump, 2105 leave the value here unchanged to 0x1000000 and set 2106 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2107 for capturing the crash dump change this value to start of 2108 the reserved region. In other words, it can be set based on 2109 the "X" value as specified in the "crashkernel=YM@XM" 2110 command line boot parameter passed to the panic-ed 2111 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2112 for more details about crash dumps. 2113 2114 Usage of bzImage for capturing the crash dump is recommended as 2115 one does not have to build two kernels. Same kernel can be used 2116 as production kernel and capture kernel. Above option should have 2117 gone away after relocatable bzImage support is introduced. But it 2118 is present because there are users out there who continue to use 2119 vmlinux for dump capture. This option should go away down the 2120 line. 2121 2122 Don't change this unless you know what you are doing. 2123 2124config RELOCATABLE 2125 bool "Build a relocatable kernel" 2126 default y 2127 help 2128 This builds a kernel image that retains relocation information 2129 so it can be loaded someplace besides the default 1MB. 2130 The relocations tend to make the kernel binary about 10% larger, 2131 but are discarded at runtime. 2132 2133 One use is for the kexec on panic case where the recovery kernel 2134 must live at a different physical address than the primary 2135 kernel. 2136 2137 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2138 it has been loaded at and the compile time physical address 2139 (CONFIG_PHYSICAL_START) is used as the minimum location. 2140 2141config RANDOMIZE_BASE 2142 bool "Randomize the address of the kernel image (KASLR)" 2143 depends on RELOCATABLE 2144 default y 2145 help 2146 In support of Kernel Address Space Layout Randomization (KASLR), 2147 this randomizes the physical address at which the kernel image 2148 is decompressed and the virtual address where the kernel 2149 image is mapped, as a security feature that deters exploit 2150 attempts relying on knowledge of the location of kernel 2151 code internals. 2152 2153 On 64-bit, the kernel physical and virtual addresses are 2154 randomized separately. The physical address will be anywhere 2155 between 16MB and the top of physical memory (up to 64TB). The 2156 virtual address will be randomized from 16MB up to 1GB (9 bits 2157 of entropy). Note that this also reduces the memory space 2158 available to kernel modules from 1.5GB to 1GB. 2159 2160 On 32-bit, the kernel physical and virtual addresses are 2161 randomized together. They will be randomized from 16MB up to 2162 512MB (8 bits of entropy). 2163 2164 Entropy is generated using the RDRAND instruction if it is 2165 supported. If RDTSC is supported, its value is mixed into 2166 the entropy pool as well. If neither RDRAND nor RDTSC are 2167 supported, then entropy is read from the i8254 timer. The 2168 usable entropy is limited by the kernel being built using 2169 2GB addressing, and that PHYSICAL_ALIGN must be at a 2170 minimum of 2MB. As a result, only 10 bits of entropy are 2171 theoretically possible, but the implementations are further 2172 limited due to memory layouts. 2173 2174 If unsure, say Y. 2175 2176# Relocation on x86 needs some additional build support 2177config X86_NEED_RELOCS 2178 def_bool y 2179 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2180 2181config PHYSICAL_ALIGN 2182 hex "Alignment value to which kernel should be aligned" 2183 default "0x200000" 2184 range 0x2000 0x1000000 if X86_32 2185 range 0x200000 0x1000000 if X86_64 2186 help 2187 This value puts the alignment restrictions on physical address 2188 where kernel is loaded and run from. Kernel is compiled for an 2189 address which meets above alignment restriction. 2190 2191 If bootloader loads the kernel at a non-aligned address and 2192 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2193 address aligned to above value and run from there. 2194 2195 If bootloader loads the kernel at a non-aligned address and 2196 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2197 load address and decompress itself to the address it has been 2198 compiled for and run from there. The address for which kernel is 2199 compiled already meets above alignment restrictions. Hence the 2200 end result is that kernel runs from a physical address meeting 2201 above alignment restrictions. 2202 2203 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2204 this value must be a multiple of 0x200000. 2205 2206 Don't change this unless you know what you are doing. 2207 2208config DYNAMIC_MEMORY_LAYOUT 2209 bool 2210 help 2211 This option makes base addresses of vmalloc and vmemmap as well as 2212 __PAGE_OFFSET movable during boot. 2213 2214config RANDOMIZE_MEMORY 2215 bool "Randomize the kernel memory sections" 2216 depends on X86_64 2217 depends on RANDOMIZE_BASE 2218 select DYNAMIC_MEMORY_LAYOUT 2219 default RANDOMIZE_BASE 2220 help 2221 Randomizes the base virtual address of kernel memory sections 2222 (physical memory mapping, vmalloc & vmemmap). This security feature 2223 makes exploits relying on predictable memory locations less reliable. 2224 2225 The order of allocations remains unchanged. Entropy is generated in 2226 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2227 configuration have in average 30,000 different possible virtual 2228 addresses for each memory section. 2229 2230 If unsure, say Y. 2231 2232config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2233 hex "Physical memory mapping padding" if EXPERT 2234 depends on RANDOMIZE_MEMORY 2235 default "0xa" if MEMORY_HOTPLUG 2236 default "0x0" 2237 range 0x1 0x40 if MEMORY_HOTPLUG 2238 range 0x0 0x40 2239 help 2240 Define the padding in terabytes added to the existing physical 2241 memory size during kernel memory randomization. It is useful 2242 for memory hotplug support but reduces the entropy available for 2243 address randomization. 2244 2245 If unsure, leave at the default value. 2246 2247config HOTPLUG_CPU 2248 def_bool y 2249 depends on SMP 2250 2251config BOOTPARAM_HOTPLUG_CPU0 2252 bool "Set default setting of cpu0_hotpluggable" 2253 depends on HOTPLUG_CPU 2254 help 2255 Set whether default state of cpu0_hotpluggable is on or off. 2256 2257 Say Y here to enable CPU0 hotplug by default. If this switch 2258 is turned on, there is no need to give cpu0_hotplug kernel 2259 parameter and the CPU0 hotplug feature is enabled by default. 2260 2261 Please note: there are two known CPU0 dependencies if you want 2262 to enable the CPU0 hotplug feature either by this switch or by 2263 cpu0_hotplug kernel parameter. 2264 2265 First, resume from hibernate or suspend always starts from CPU0. 2266 So hibernate and suspend are prevented if CPU0 is offline. 2267 2268 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2269 offline if any interrupt can not migrate out of CPU0. There may 2270 be other CPU0 dependencies. 2271 2272 Please make sure the dependencies are under your control before 2273 you enable this feature. 2274 2275 Say N if you don't want to enable CPU0 hotplug feature by default. 2276 You still can enable the CPU0 hotplug feature at boot by kernel 2277 parameter cpu0_hotplug. 2278 2279config DEBUG_HOTPLUG_CPU0 2280 def_bool n 2281 prompt "Debug CPU0 hotplug" 2282 depends on HOTPLUG_CPU 2283 help 2284 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2285 soon as possible and boots up userspace with CPU0 offlined. User 2286 can online CPU0 back after boot time. 2287 2288 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2289 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2290 compilation or giving cpu0_hotplug kernel parameter at boot. 2291 2292 If unsure, say N. 2293 2294config COMPAT_VDSO 2295 def_bool n 2296 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2297 depends on COMPAT_32 2298 help 2299 Certain buggy versions of glibc will crash if they are 2300 presented with a 32-bit vDSO that is not mapped at the address 2301 indicated in its segment table. 2302 2303 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2304 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2305 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2306 the only released version with the bug, but OpenSUSE 9 2307 contains a buggy "glibc 2.3.2". 2308 2309 The symptom of the bug is that everything crashes on startup, saying: 2310 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2311 2312 Saying Y here changes the default value of the vdso32 boot 2313 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2314 This works around the glibc bug but hurts performance. 2315 2316 If unsure, say N: if you are compiling your own kernel, you 2317 are unlikely to be using a buggy version of glibc. 2318 2319choice 2320 prompt "vsyscall table for legacy applications" 2321 depends on X86_64 2322 default LEGACY_VSYSCALL_XONLY 2323 help 2324 Legacy user code that does not know how to find the vDSO expects 2325 to be able to issue three syscalls by calling fixed addresses in 2326 kernel space. Since this location is not randomized with ASLR, 2327 it can be used to assist security vulnerability exploitation. 2328 2329 This setting can be changed at boot time via the kernel command 2330 line parameter vsyscall=[emulate|xonly|none]. 2331 2332 On a system with recent enough glibc (2.14 or newer) and no 2333 static binaries, you can say None without a performance penalty 2334 to improve security. 2335 2336 If unsure, select "Emulate execution only". 2337 2338 config LEGACY_VSYSCALL_EMULATE 2339 bool "Full emulation" 2340 help 2341 The kernel traps and emulates calls into the fixed vsyscall 2342 address mapping. This makes the mapping non-executable, but 2343 it still contains readable known contents, which could be 2344 used in certain rare security vulnerability exploits. This 2345 configuration is recommended when using legacy userspace 2346 that still uses vsyscalls along with legacy binary 2347 instrumentation tools that require code to be readable. 2348 2349 An example of this type of legacy userspace is running 2350 Pin on an old binary that still uses vsyscalls. 2351 2352 config LEGACY_VSYSCALL_XONLY 2353 bool "Emulate execution only" 2354 help 2355 The kernel traps and emulates calls into the fixed vsyscall 2356 address mapping and does not allow reads. This 2357 configuration is recommended when userspace might use the 2358 legacy vsyscall area but support for legacy binary 2359 instrumentation of legacy code is not needed. It mitigates 2360 certain uses of the vsyscall area as an ASLR-bypassing 2361 buffer. 2362 2363 config LEGACY_VSYSCALL_NONE 2364 bool "None" 2365 help 2366 There will be no vsyscall mapping at all. This will 2367 eliminate any risk of ASLR bypass due to the vsyscall 2368 fixed address mapping. Attempts to use the vsyscalls 2369 will be reported to dmesg, so that either old or 2370 malicious userspace programs can be identified. 2371 2372endchoice 2373 2374config CMDLINE_BOOL 2375 bool "Built-in kernel command line" 2376 help 2377 Allow for specifying boot arguments to the kernel at 2378 build time. On some systems (e.g. embedded ones), it is 2379 necessary or convenient to provide some or all of the 2380 kernel boot arguments with the kernel itself (that is, 2381 to not rely on the boot loader to provide them.) 2382 2383 To compile command line arguments into the kernel, 2384 set this option to 'Y', then fill in the 2385 boot arguments in CONFIG_CMDLINE. 2386 2387 Systems with fully functional boot loaders (i.e. non-embedded) 2388 should leave this option set to 'N'. 2389 2390config CMDLINE 2391 string "Built-in kernel command string" 2392 depends on CMDLINE_BOOL 2393 default "" 2394 help 2395 Enter arguments here that should be compiled into the kernel 2396 image and used at boot time. If the boot loader provides a 2397 command line at boot time, it is appended to this string to 2398 form the full kernel command line, when the system boots. 2399 2400 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2401 change this behavior. 2402 2403 In most cases, the command line (whether built-in or provided 2404 by the boot loader) should specify the device for the root 2405 file system. 2406 2407config CMDLINE_OVERRIDE 2408 bool "Built-in command line overrides boot loader arguments" 2409 depends on CMDLINE_BOOL && CMDLINE != "" 2410 help 2411 Set this option to 'Y' to have the kernel ignore the boot loader 2412 command line, and use ONLY the built-in command line. 2413 2414 This is used to work around broken boot loaders. This should 2415 be set to 'N' under normal conditions. 2416 2417config MODIFY_LDT_SYSCALL 2418 bool "Enable the LDT (local descriptor table)" if EXPERT 2419 default y 2420 help 2421 Linux can allow user programs to install a per-process x86 2422 Local Descriptor Table (LDT) using the modify_ldt(2) system 2423 call. This is required to run 16-bit or segmented code such as 2424 DOSEMU or some Wine programs. It is also used by some very old 2425 threading libraries. 2426 2427 Enabling this feature adds a small amount of overhead to 2428 context switches and increases the low-level kernel attack 2429 surface. Disabling it removes the modify_ldt(2) system call. 2430 2431 Saying 'N' here may make sense for embedded or server kernels. 2432 2433config STRICT_SIGALTSTACK_SIZE 2434 bool "Enforce strict size checking for sigaltstack" 2435 depends on DYNAMIC_SIGFRAME 2436 help 2437 For historical reasons MINSIGSTKSZ is a constant which became 2438 already too small with AVX512 support. Add a mechanism to 2439 enforce strict checking of the sigaltstack size against the 2440 real size of the FPU frame. This option enables the check 2441 by default. It can also be controlled via the kernel command 2442 line option 'strict_sas_size' independent of this config 2443 switch. Enabling it might break existing applications which 2444 allocate a too small sigaltstack but 'work' because they 2445 never get a signal delivered. 2446 2447 Say 'N' unless you want to really enforce this check. 2448 2449source "kernel/livepatch/Kconfig" 2450 2451endmenu 2452 2453config ARCH_HAS_ADD_PAGES 2454 def_bool y 2455 depends on ARCH_ENABLE_MEMORY_HOTPLUG 2456 2457config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2458 def_bool y 2459 2460menu "Power management and ACPI options" 2461 2462config ARCH_HIBERNATION_HEADER 2463 def_bool y 2464 depends on HIBERNATION 2465 2466source "kernel/power/Kconfig" 2467 2468source "drivers/acpi/Kconfig" 2469 2470config X86_APM_BOOT 2471 def_bool y 2472 depends on APM 2473 2474menuconfig APM 2475 tristate "APM (Advanced Power Management) BIOS support" 2476 depends on X86_32 && PM_SLEEP 2477 help 2478 APM is a BIOS specification for saving power using several different 2479 techniques. This is mostly useful for battery powered laptops with 2480 APM compliant BIOSes. If you say Y here, the system time will be 2481 reset after a RESUME operation, the /proc/apm device will provide 2482 battery status information, and user-space programs will receive 2483 notification of APM "events" (e.g. battery status change). 2484 2485 If you select "Y" here, you can disable actual use of the APM 2486 BIOS by passing the "apm=off" option to the kernel at boot time. 2487 2488 Note that the APM support is almost completely disabled for 2489 machines with more than one CPU. 2490 2491 In order to use APM, you will need supporting software. For location 2492 and more information, read <file:Documentation/power/apm-acpi.rst> 2493 and the Battery Powered Linux mini-HOWTO, available from 2494 <http://www.tldp.org/docs.html#howto>. 2495 2496 This driver does not spin down disk drives (see the hdparm(8) 2497 manpage ("man 8 hdparm") for that), and it doesn't turn off 2498 VESA-compliant "green" monitors. 2499 2500 This driver does not support the TI 4000M TravelMate and the ACER 2501 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2502 desktop machines also don't have compliant BIOSes, and this driver 2503 may cause those machines to panic during the boot phase. 2504 2505 Generally, if you don't have a battery in your machine, there isn't 2506 much point in using this driver and you should say N. If you get 2507 random kernel OOPSes or reboots that don't seem to be related to 2508 anything, try disabling/enabling this option (or disabling/enabling 2509 APM in your BIOS). 2510 2511 Some other things you should try when experiencing seemingly random, 2512 "weird" problems: 2513 2514 1) make sure that you have enough swap space and that it is 2515 enabled. 2516 2) pass the "no-hlt" option to the kernel 2517 3) switch on floating point emulation in the kernel and pass 2518 the "no387" option to the kernel 2519 4) pass the "floppy=nodma" option to the kernel 2520 5) pass the "mem=4M" option to the kernel (thereby disabling 2521 all but the first 4 MB of RAM) 2522 6) make sure that the CPU is not over clocked. 2523 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2524 8) disable the cache from your BIOS settings 2525 9) install a fan for the video card or exchange video RAM 2526 10) install a better fan for the CPU 2527 11) exchange RAM chips 2528 12) exchange the motherboard. 2529 2530 To compile this driver as a module, choose M here: the 2531 module will be called apm. 2532 2533if APM 2534 2535config APM_IGNORE_USER_SUSPEND 2536 bool "Ignore USER SUSPEND" 2537 help 2538 This option will ignore USER SUSPEND requests. On machines with a 2539 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2540 series notebooks, it is necessary to say Y because of a BIOS bug. 2541 2542config APM_DO_ENABLE 2543 bool "Enable PM at boot time" 2544 help 2545 Enable APM features at boot time. From page 36 of the APM BIOS 2546 specification: "When disabled, the APM BIOS does not automatically 2547 power manage devices, enter the Standby State, enter the Suspend 2548 State, or take power saving steps in response to CPU Idle calls." 2549 This driver will make CPU Idle calls when Linux is idle (unless this 2550 feature is turned off -- see "Do CPU IDLE calls", below). This 2551 should always save battery power, but more complicated APM features 2552 will be dependent on your BIOS implementation. You may need to turn 2553 this option off if your computer hangs at boot time when using APM 2554 support, or if it beeps continuously instead of suspending. Turn 2555 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2556 T400CDT. This is off by default since most machines do fine without 2557 this feature. 2558 2559config APM_CPU_IDLE 2560 depends on CPU_IDLE 2561 bool "Make CPU Idle calls when idle" 2562 help 2563 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2564 On some machines, this can activate improved power savings, such as 2565 a slowed CPU clock rate, when the machine is idle. These idle calls 2566 are made after the idle loop has run for some length of time (e.g., 2567 333 mS). On some machines, this will cause a hang at boot time or 2568 whenever the CPU becomes idle. (On machines with more than one CPU, 2569 this option does nothing.) 2570 2571config APM_DISPLAY_BLANK 2572 bool "Enable console blanking using APM" 2573 help 2574 Enable console blanking using the APM. Some laptops can use this to 2575 turn off the LCD backlight when the screen blanker of the Linux 2576 virtual console blanks the screen. Note that this is only used by 2577 the virtual console screen blanker, and won't turn off the backlight 2578 when using the X Window system. This also doesn't have anything to 2579 do with your VESA-compliant power-saving monitor. Further, this 2580 option doesn't work for all laptops -- it might not turn off your 2581 backlight at all, or it might print a lot of errors to the console, 2582 especially if you are using gpm. 2583 2584config APM_ALLOW_INTS 2585 bool "Allow interrupts during APM BIOS calls" 2586 help 2587 Normally we disable external interrupts while we are making calls to 2588 the APM BIOS as a measure to lessen the effects of a badly behaving 2589 BIOS implementation. The BIOS should reenable interrupts if it 2590 needs to. Unfortunately, some BIOSes do not -- especially those in 2591 many of the newer IBM Thinkpads. If you experience hangs when you 2592 suspend, try setting this to Y. Otherwise, say N. 2593 2594endif # APM 2595 2596source "drivers/cpufreq/Kconfig" 2597 2598source "drivers/cpuidle/Kconfig" 2599 2600source "drivers/idle/Kconfig" 2601 2602endmenu 2603 2604 2605menu "Bus options (PCI etc.)" 2606 2607choice 2608 prompt "PCI access mode" 2609 depends on X86_32 && PCI 2610 default PCI_GOANY 2611 help 2612 On PCI systems, the BIOS can be used to detect the PCI devices and 2613 determine their configuration. However, some old PCI motherboards 2614 have BIOS bugs and may crash if this is done. Also, some embedded 2615 PCI-based systems don't have any BIOS at all. Linux can also try to 2616 detect the PCI hardware directly without using the BIOS. 2617 2618 With this option, you can specify how Linux should detect the 2619 PCI devices. If you choose "BIOS", the BIOS will be used, 2620 if you choose "Direct", the BIOS won't be used, and if you 2621 choose "MMConfig", then PCI Express MMCONFIG will be used. 2622 If you choose "Any", the kernel will try MMCONFIG, then the 2623 direct access method and falls back to the BIOS if that doesn't 2624 work. If unsure, go with the default, which is "Any". 2625 2626config PCI_GOBIOS 2627 bool "BIOS" 2628 2629config PCI_GOMMCONFIG 2630 bool "MMConfig" 2631 2632config PCI_GODIRECT 2633 bool "Direct" 2634 2635config PCI_GOOLPC 2636 bool "OLPC XO-1" 2637 depends on OLPC 2638 2639config PCI_GOANY 2640 bool "Any" 2641 2642endchoice 2643 2644config PCI_BIOS 2645 def_bool y 2646 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2647 2648# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2649config PCI_DIRECT 2650 def_bool y 2651 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2652 2653config PCI_MMCONFIG 2654 bool "Support mmconfig PCI config space access" if X86_64 2655 default y 2656 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2657 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2658 2659config PCI_OLPC 2660 def_bool y 2661 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2662 2663config PCI_XEN 2664 def_bool y 2665 depends on PCI && XEN 2666 2667config MMCONF_FAM10H 2668 def_bool y 2669 depends on X86_64 && PCI_MMCONFIG && ACPI 2670 2671config PCI_CNB20LE_QUIRK 2672 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2673 depends on PCI 2674 help 2675 Read the PCI windows out of the CNB20LE host bridge. This allows 2676 PCI hotplug to work on systems with the CNB20LE chipset which do 2677 not have ACPI. 2678 2679 There's no public spec for this chipset, and this functionality 2680 is known to be incomplete. 2681 2682 You should say N unless you know you need this. 2683 2684config ISA_BUS 2685 bool "ISA bus support on modern systems" if EXPERT 2686 help 2687 Expose ISA bus device drivers and options available for selection and 2688 configuration. Enable this option if your target machine has an ISA 2689 bus. ISA is an older system, displaced by PCI and newer bus 2690 architectures -- if your target machine is modern, it probably does 2691 not have an ISA bus. 2692 2693 If unsure, say N. 2694 2695# x86_64 have no ISA slots, but can have ISA-style DMA. 2696config ISA_DMA_API 2697 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2698 default y 2699 help 2700 Enables ISA-style DMA support for devices requiring such controllers. 2701 If unsure, say Y. 2702 2703if X86_32 2704 2705config ISA 2706 bool "ISA support" 2707 help 2708 Find out whether you have ISA slots on your motherboard. ISA is the 2709 name of a bus system, i.e. the way the CPU talks to the other stuff 2710 inside your box. Other bus systems are PCI, EISA, MicroChannel 2711 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2712 newer boards don't support it. If you have ISA, say Y, otherwise N. 2713 2714config SCx200 2715 tristate "NatSemi SCx200 support" 2716 help 2717 This provides basic support for National Semiconductor's 2718 (now AMD's) Geode processors. The driver probes for the 2719 PCI-IDs of several on-chip devices, so its a good dependency 2720 for other scx200_* drivers. 2721 2722 If compiled as a module, the driver is named scx200. 2723 2724config SCx200HR_TIMER 2725 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2726 depends on SCx200 2727 default y 2728 help 2729 This driver provides a clocksource built upon the on-chip 2730 27MHz high-resolution timer. Its also a workaround for 2731 NSC Geode SC-1100's buggy TSC, which loses time when the 2732 processor goes idle (as is done by the scheduler). The 2733 other workaround is idle=poll boot option. 2734 2735config OLPC 2736 bool "One Laptop Per Child support" 2737 depends on !X86_PAE 2738 select GPIOLIB 2739 select OF 2740 select OF_PROMTREE 2741 select IRQ_DOMAIN 2742 select OLPC_EC 2743 help 2744 Add support for detecting the unique features of the OLPC 2745 XO hardware. 2746 2747config OLPC_XO1_PM 2748 bool "OLPC XO-1 Power Management" 2749 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2750 help 2751 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2752 2753config OLPC_XO1_RTC 2754 bool "OLPC XO-1 Real Time Clock" 2755 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2756 help 2757 Add support for the XO-1 real time clock, which can be used as a 2758 programmable wakeup source. 2759 2760config OLPC_XO1_SCI 2761 bool "OLPC XO-1 SCI extras" 2762 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2763 depends on INPUT=y 2764 select POWER_SUPPLY 2765 help 2766 Add support for SCI-based features of the OLPC XO-1 laptop: 2767 - EC-driven system wakeups 2768 - Power button 2769 - Ebook switch 2770 - Lid switch 2771 - AC adapter status updates 2772 - Battery status updates 2773 2774config OLPC_XO15_SCI 2775 bool "OLPC XO-1.5 SCI extras" 2776 depends on OLPC && ACPI 2777 select POWER_SUPPLY 2778 help 2779 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2780 - EC-driven system wakeups 2781 - AC adapter status updates 2782 - Battery status updates 2783 2784config ALIX 2785 bool "PCEngines ALIX System Support (LED setup)" 2786 select GPIOLIB 2787 help 2788 This option enables system support for the PCEngines ALIX. 2789 At present this just sets up LEDs for GPIO control on 2790 ALIX2/3/6 boards. However, other system specific setup should 2791 get added here. 2792 2793 Note: You must still enable the drivers for GPIO and LED support 2794 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2795 2796 Note: You have to set alix.force=1 for boards with Award BIOS. 2797 2798config NET5501 2799 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2800 select GPIOLIB 2801 help 2802 This option enables system support for the Soekris Engineering net5501. 2803 2804config GEOS 2805 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2806 select GPIOLIB 2807 depends on DMI 2808 help 2809 This option enables system support for the Traverse Technologies GEOS. 2810 2811config TS5500 2812 bool "Technologic Systems TS-5500 platform support" 2813 depends on MELAN 2814 select CHECK_SIGNATURE 2815 select NEW_LEDS 2816 select LEDS_CLASS 2817 help 2818 This option enables system support for the Technologic Systems TS-5500. 2819 2820endif # X86_32 2821 2822config AMD_NB 2823 def_bool y 2824 depends on CPU_SUP_AMD && PCI 2825 2826endmenu 2827 2828 2829menu "Binary Emulations" 2830 2831config IA32_EMULATION 2832 bool "IA32 Emulation" 2833 depends on X86_64 2834 select ARCH_WANT_OLD_COMPAT_IPC 2835 select BINFMT_ELF 2836 select COMPAT_OLD_SIGACTION 2837 help 2838 Include code to run legacy 32-bit programs under a 2839 64-bit kernel. You should likely turn this on, unless you're 2840 100% sure that you don't have any 32-bit programs left. 2841 2842config IA32_AOUT 2843 tristate "IA32 a.out support" 2844 depends on IA32_EMULATION 2845 depends on BROKEN 2846 help 2847 Support old a.out binaries in the 32bit emulation. 2848 2849config X86_X32_ABI 2850 bool "x32 ABI for 64-bit mode" 2851 depends on X86_64 2852 # llvm-objcopy does not convert x86_64 .note.gnu.property or 2853 # compressed debug sections to x86_x32 properly: 2854 # https://github.com/ClangBuiltLinux/linux/issues/514 2855 # https://github.com/ClangBuiltLinux/linux/issues/1141 2856 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 2857 help 2858 Include code to run binaries for the x32 native 32-bit ABI 2859 for 64-bit processors. An x32 process gets access to the 2860 full 64-bit register file and wide data path while leaving 2861 pointers at 32 bits for smaller memory footprint. 2862 2863config COMPAT_32 2864 def_bool y 2865 depends on IA32_EMULATION || X86_32 2866 select HAVE_UID16 2867 select OLD_SIGSUSPEND3 2868 2869config COMPAT 2870 def_bool y 2871 depends on IA32_EMULATION || X86_X32_ABI 2872 2873if COMPAT 2874config COMPAT_FOR_U64_ALIGNMENT 2875 def_bool y 2876 2877config SYSVIPC_COMPAT 2878 def_bool y 2879 depends on SYSVIPC 2880endif 2881 2882endmenu 2883 2884 2885config HAVE_ATOMIC_IOMAP 2886 def_bool y 2887 depends on X86_32 2888 2889source "arch/x86/kvm/Kconfig" 2890 2891source "arch/x86/Kconfig.assembler" 2892