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_FILTER_PGPROT 80 select ARCH_HAS_FORTIFY_SOURCE 81 select ARCH_HAS_GCOV_PROFILE_ALL 82 select ARCH_HAS_KCOV if X86_64 83 select ARCH_HAS_MEM_ENCRYPT 84 select ARCH_HAS_MEMBARRIER_SYNC_CORE 85 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 86 select ARCH_HAS_PMEM_API if X86_64 87 select ARCH_HAS_PTE_DEVMAP if X86_64 88 select ARCH_HAS_PTE_SPECIAL 89 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 90 select ARCH_HAS_COPY_MC if X86_64 91 select ARCH_HAS_SET_MEMORY 92 select ARCH_HAS_SET_DIRECT_MAP 93 select ARCH_HAS_STRICT_KERNEL_RWX 94 select ARCH_HAS_STRICT_MODULE_RWX 95 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 96 select ARCH_HAS_SYSCALL_WRAPPER 97 select ARCH_HAS_UBSAN_SANITIZE_ALL 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_LD_ORPHAN_WARN 125 select ARCH_WANTS_THP_SWAP if X86_64 126 select ARCH_HAS_PARANOID_L1D_FLUSH 127 select BUILDTIME_TABLE_SORT 128 select CLKEVT_I8253 129 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 130 select CLOCKSOURCE_WATCHDOG 131 select DCACHE_WORD_ACCESS 132 select DYNAMIC_SIGFRAME 133 select EDAC_ATOMIC_SCRUB 134 select EDAC_SUPPORT 135 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 136 select GENERIC_CLOCKEVENTS_MIN_ADJUST 137 select GENERIC_CMOS_UPDATE 138 select GENERIC_CPU_AUTOPROBE 139 select GENERIC_CPU_VULNERABILITIES 140 select GENERIC_EARLY_IOREMAP 141 select GENERIC_ENTRY 142 select GENERIC_IOMAP 143 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 144 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 145 select GENERIC_IRQ_MIGRATION if SMP 146 select GENERIC_IRQ_PROBE 147 select GENERIC_IRQ_RESERVATION_MODE 148 select GENERIC_IRQ_SHOW 149 select GENERIC_PENDING_IRQ if SMP 150 select GENERIC_PTDUMP 151 select GENERIC_SMP_IDLE_THREAD 152 select GENERIC_TIME_VSYSCALL 153 select GENERIC_GETTIMEOFDAY 154 select GENERIC_VDSO_TIME_NS 155 select GUP_GET_PTE_LOW_HIGH if X86_PAE 156 select HARDIRQS_SW_RESEND 157 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 158 select HAVE_ACPI_APEI if ACPI 159 select HAVE_ACPI_APEI_NMI if ACPI 160 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 161 select HAVE_ARCH_AUDITSYSCALL 162 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 163 select HAVE_ARCH_HUGE_VMALLOC if X86_64 164 select HAVE_ARCH_JUMP_LABEL 165 select HAVE_ARCH_JUMP_LABEL_RELATIVE 166 select HAVE_ARCH_KASAN if X86_64 167 select HAVE_ARCH_KASAN_VMALLOC if X86_64 168 select HAVE_ARCH_KFENCE 169 select HAVE_ARCH_KGDB 170 select HAVE_ARCH_MMAP_RND_BITS if MMU 171 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 172 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 173 select HAVE_ARCH_PREL32_RELOCATIONS 174 select HAVE_ARCH_SECCOMP_FILTER 175 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 176 select HAVE_ARCH_STACKLEAK 177 select HAVE_ARCH_TRACEHOOK 178 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 179 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 180 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 181 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 182 select HAVE_ARCH_VMAP_STACK if X86_64 183 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 184 select HAVE_ARCH_WITHIN_STACK_FRAMES 185 select HAVE_ASM_MODVERSIONS 186 select HAVE_CMPXCHG_DOUBLE 187 select HAVE_CMPXCHG_LOCAL 188 select HAVE_CONTEXT_TRACKING if X86_64 189 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING 190 select HAVE_C_RECORDMCOUNT 191 select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION 192 select HAVE_BUILDTIME_MCOUNT_SORT 193 select HAVE_DEBUG_KMEMLEAK 194 select HAVE_DMA_CONTIGUOUS 195 select HAVE_DYNAMIC_FTRACE 196 select HAVE_DYNAMIC_FTRACE_WITH_REGS 197 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 198 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 199 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 200 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 201 select HAVE_EBPF_JIT 202 select HAVE_EFFICIENT_UNALIGNED_ACCESS 203 select HAVE_EISA 204 select HAVE_EXIT_THREAD 205 select HAVE_FAST_GUP 206 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 207 select HAVE_FTRACE_MCOUNT_RECORD 208 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 209 select HAVE_FUNCTION_TRACER 210 select HAVE_GCC_PLUGINS 211 select HAVE_HW_BREAKPOINT 212 select HAVE_IOREMAP_PROT 213 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 214 select HAVE_IRQ_TIME_ACCOUNTING 215 select HAVE_KERNEL_BZIP2 216 select HAVE_KERNEL_GZIP 217 select HAVE_KERNEL_LZ4 218 select HAVE_KERNEL_LZMA 219 select HAVE_KERNEL_LZO 220 select HAVE_KERNEL_XZ 221 select HAVE_KERNEL_ZSTD 222 select HAVE_KPROBES 223 select HAVE_KPROBES_ON_FTRACE 224 select HAVE_FUNCTION_ERROR_INJECTION 225 select HAVE_KRETPROBES 226 select HAVE_RETHOOK 227 select HAVE_KVM 228 select HAVE_LIVEPATCH if X86_64 229 select HAVE_MIXED_BREAKPOINTS_REGS 230 select HAVE_MOD_ARCH_SPECIFIC 231 select HAVE_MOVE_PMD 232 select HAVE_MOVE_PUD 233 select HAVE_NMI 234 select HAVE_OPTPROBES 235 select HAVE_PCSPKR_PLATFORM 236 select HAVE_PERF_EVENTS 237 select HAVE_PERF_EVENTS_NMI 238 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 239 select HAVE_PCI 240 select HAVE_PERF_REGS 241 select HAVE_PERF_USER_STACK_DUMP 242 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 243 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 244 select HAVE_REGS_AND_STACK_ACCESS_API 245 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 246 select HAVE_FUNCTION_ARG_ACCESS_API 247 select HAVE_SETUP_PER_CPU_AREA 248 select HAVE_SOFTIRQ_ON_OWN_STACK 249 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 250 select HAVE_STACK_VALIDATION if X86_64 251 select HAVE_STATIC_CALL 252 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 253 select HAVE_PREEMPT_DYNAMIC_CALL 254 select HAVE_RSEQ 255 select HAVE_SYSCALL_TRACEPOINTS 256 select HAVE_UNSTABLE_SCHED_CLOCK 257 select HAVE_USER_RETURN_NOTIFIER 258 select HAVE_GENERIC_VDSO 259 select HOTPLUG_SMT if SMP 260 select IRQ_FORCED_THREADING 261 select NEED_PER_CPU_EMBED_FIRST_CHUNK 262 select NEED_PER_CPU_PAGE_FIRST_CHUNK 263 select NEED_SG_DMA_LENGTH 264 select PCI_DOMAINS if PCI 265 select PCI_LOCKLESS_CONFIG if PCI 266 select PERF_EVENTS 267 select RTC_LIB 268 select RTC_MC146818_LIB 269 select SPARSE_IRQ 270 select SRCU 271 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 272 select SYSCTL_EXCEPTION_TRACE 273 select THREAD_INFO_IN_TASK 274 select TRACE_IRQFLAGS_SUPPORT 275 select USER_STACKTRACE_SUPPORT 276 select VIRT_TO_BUS 277 select HAVE_ARCH_KCSAN if X86_64 278 select X86_FEATURE_NAMES if PROC_FS 279 select PROC_PID_ARCH_STATUS if PROC_FS 280 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 281 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 282 283config INSTRUCTION_DECODER 284 def_bool y 285 depends on KPROBES || PERF_EVENTS || UPROBES 286 287config OUTPUT_FORMAT 288 string 289 default "elf32-i386" if X86_32 290 default "elf64-x86-64" if X86_64 291 292config LOCKDEP_SUPPORT 293 def_bool y 294 295config STACKTRACE_SUPPORT 296 def_bool y 297 298config MMU 299 def_bool y 300 301config ARCH_MMAP_RND_BITS_MIN 302 default 28 if 64BIT 303 default 8 304 305config ARCH_MMAP_RND_BITS_MAX 306 default 32 if 64BIT 307 default 16 308 309config ARCH_MMAP_RND_COMPAT_BITS_MIN 310 default 8 311 312config ARCH_MMAP_RND_COMPAT_BITS_MAX 313 default 16 314 315config SBUS 316 bool 317 318config GENERIC_ISA_DMA 319 def_bool y 320 depends on ISA_DMA_API 321 322config GENERIC_BUG 323 def_bool y 324 depends on BUG 325 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 326 327config GENERIC_BUG_RELATIVE_POINTERS 328 bool 329 330config ARCH_MAY_HAVE_PC_FDC 331 def_bool y 332 depends on ISA_DMA_API 333 334config GENERIC_CALIBRATE_DELAY 335 def_bool y 336 337config ARCH_HAS_CPU_RELAX 338 def_bool y 339 340config ARCH_HIBERNATION_POSSIBLE 341 def_bool y 342 343config ARCH_NR_GPIO 344 int 345 default 1024 if X86_64 346 default 512 347 348config ARCH_SUSPEND_POSSIBLE 349 def_bool y 350 351config AUDIT_ARCH 352 def_bool y if X86_64 353 354config KASAN_SHADOW_OFFSET 355 hex 356 depends on KASAN 357 default 0xdffffc0000000000 358 359config HAVE_INTEL_TXT 360 def_bool y 361 depends on INTEL_IOMMU && ACPI 362 363config X86_32_SMP 364 def_bool y 365 depends on X86_32 && SMP 366 367config X86_64_SMP 368 def_bool y 369 depends on X86_64 && SMP 370 371config ARCH_SUPPORTS_UPROBES 372 def_bool y 373 374config FIX_EARLYCON_MEM 375 def_bool y 376 377config DYNAMIC_PHYSICAL_MASK 378 bool 379 380config PGTABLE_LEVELS 381 int 382 default 5 if X86_5LEVEL 383 default 4 if X86_64 384 default 3 if X86_PAE 385 default 2 386 387config CC_HAS_SANE_STACKPROTECTOR 388 bool 389 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 390 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 391 help 392 We have to make sure stack protector is unconditionally disabled if 393 the compiler produces broken code or if it does not let us control 394 the segment on 32-bit kernels. 395 396menu "Processor type and features" 397 398config SMP 399 bool "Symmetric multi-processing support" 400 help 401 This enables support for systems with more than one CPU. If you have 402 a system with only one CPU, say N. If you have a system with more 403 than one CPU, say Y. 404 405 If you say N here, the kernel will run on uni- and multiprocessor 406 machines, but will use only one CPU of a multiprocessor machine. If 407 you say Y here, the kernel will run on many, but not all, 408 uniprocessor machines. On a uniprocessor machine, the kernel 409 will run faster if you say N here. 410 411 Note that if you say Y here and choose architecture "586" or 412 "Pentium" under "Processor family", the kernel will not work on 486 413 architectures. Similarly, multiprocessor kernels for the "PPro" 414 architecture may not work on all Pentium based boards. 415 416 People using multiprocessor machines who say Y here should also say 417 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 418 Management" code will be disabled if you say Y here. 419 420 See also <file:Documentation/x86/i386/IO-APIC.rst>, 421 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 422 <http://www.tldp.org/docs.html#howto>. 423 424 If you don't know what to do here, say N. 425 426config X86_FEATURE_NAMES 427 bool "Processor feature human-readable names" if EMBEDDED 428 default y 429 help 430 This option compiles in a table of x86 feature bits and corresponding 431 names. This is required to support /proc/cpuinfo and a few kernel 432 messages. You can disable this to save space, at the expense of 433 making those few kernel messages show numeric feature bits instead. 434 435 If in doubt, say Y. 436 437config X86_X2APIC 438 bool "Support x2apic" 439 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 440 help 441 This enables x2apic support on CPUs that have this feature. 442 443 This allows 32-bit apic IDs (so it can support very large systems), 444 and accesses the local apic via MSRs not via mmio. 445 446 If you don't know what to do here, say N. 447 448config X86_MPPARSE 449 bool "Enable MPS table" if ACPI 450 default y 451 depends on X86_LOCAL_APIC 452 help 453 For old smp systems that do not have proper acpi support. Newer systems 454 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 455 456config GOLDFISH 457 def_bool y 458 depends on X86_GOLDFISH 459 460config RETPOLINE 461 bool "Avoid speculative indirect branches in kernel" 462 default y 463 help 464 Compile kernel with the retpoline compiler options to guard against 465 kernel-to-user data leaks by avoiding speculative indirect 466 branches. Requires a compiler with -mindirect-branch=thunk-extern 467 support for full protection. The kernel may run slower. 468 469config CC_HAS_SLS 470 def_bool $(cc-option,-mharden-sls=all) 471 472config SLS 473 bool "Mitigate Straight-Line-Speculation" 474 depends on CC_HAS_SLS && X86_64 475 default n 476 help 477 Compile the kernel with straight-line-speculation options to guard 478 against straight line speculation. The kernel image might be slightly 479 larger. 480 481config X86_CPU_RESCTRL 482 bool "x86 CPU resource control support" 483 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 484 select KERNFS 485 select PROC_CPU_RESCTRL if PROC_FS 486 help 487 Enable x86 CPU resource control support. 488 489 Provide support for the allocation and monitoring of system resources 490 usage by the CPU. 491 492 Intel calls this Intel Resource Director Technology 493 (Intel(R) RDT). More information about RDT can be found in the 494 Intel x86 Architecture Software Developer Manual. 495 496 AMD calls this AMD Platform Quality of Service (AMD QoS). 497 More information about AMD QoS can be found in the AMD64 Technology 498 Platform Quality of Service Extensions manual. 499 500 Say N if unsure. 501 502if X86_32 503config X86_BIGSMP 504 bool "Support for big SMP systems with more than 8 CPUs" 505 depends on SMP 506 help 507 This option is needed for the systems that have more than 8 CPUs. 508 509config X86_EXTENDED_PLATFORM 510 bool "Support for extended (non-PC) x86 platforms" 511 default y 512 help 513 If you disable this option then the kernel will only support 514 standard PC platforms. (which covers the vast majority of 515 systems out there.) 516 517 If you enable this option then you'll be able to select support 518 for the following (non-PC) 32 bit x86 platforms: 519 Goldfish (Android emulator) 520 AMD Elan 521 RDC R-321x SoC 522 SGI 320/540 (Visual Workstation) 523 STA2X11-based (e.g. Northville) 524 Moorestown MID devices 525 526 If you have one of these systems, or if you want to build a 527 generic distribution kernel, say Y here - otherwise say N. 528endif 529 530if X86_64 531config X86_EXTENDED_PLATFORM 532 bool "Support for extended (non-PC) x86 platforms" 533 default y 534 help 535 If you disable this option then the kernel will only support 536 standard PC platforms. (which covers the vast majority of 537 systems out there.) 538 539 If you enable this option then you'll be able to select support 540 for the following (non-PC) 64 bit x86 platforms: 541 Numascale NumaChip 542 ScaleMP vSMP 543 SGI Ultraviolet 544 545 If you have one of these systems, or if you want to build a 546 generic distribution kernel, say Y here - otherwise say N. 547endif 548# This is an alphabetically sorted list of 64 bit extended platforms 549# Please maintain the alphabetic order if and when there are additions 550config X86_NUMACHIP 551 bool "Numascale NumaChip" 552 depends on X86_64 553 depends on X86_EXTENDED_PLATFORM 554 depends on NUMA 555 depends on SMP 556 depends on X86_X2APIC 557 depends on PCI_MMCONFIG 558 help 559 Adds support for Numascale NumaChip large-SMP systems. Needed to 560 enable more than ~168 cores. 561 If you don't have one of these, you should say N here. 562 563config X86_VSMP 564 bool "ScaleMP vSMP" 565 select HYPERVISOR_GUEST 566 select PARAVIRT 567 depends on X86_64 && PCI 568 depends on X86_EXTENDED_PLATFORM 569 depends on SMP 570 help 571 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 572 supposed to run on these EM64T-based machines. Only choose this option 573 if you have one of these machines. 574 575config X86_UV 576 bool "SGI Ultraviolet" 577 depends on X86_64 578 depends on X86_EXTENDED_PLATFORM 579 depends on NUMA 580 depends on EFI 581 depends on KEXEC_CORE 582 depends on X86_X2APIC 583 depends on PCI 584 help 585 This option is needed in order to support SGI Ultraviolet systems. 586 If you don't have one of these, you should say N here. 587 588# Following is an alphabetically sorted list of 32 bit extended platforms 589# Please maintain the alphabetic order if and when there are additions 590 591config X86_GOLDFISH 592 bool "Goldfish (Virtual Platform)" 593 depends on X86_EXTENDED_PLATFORM 594 help 595 Enable support for the Goldfish virtual platform used primarily 596 for Android development. Unless you are building for the Android 597 Goldfish emulator say N here. 598 599config X86_INTEL_CE 600 bool "CE4100 TV platform" 601 depends on PCI 602 depends on PCI_GODIRECT 603 depends on X86_IO_APIC 604 depends on X86_32 605 depends on X86_EXTENDED_PLATFORM 606 select X86_REBOOTFIXUPS 607 select OF 608 select OF_EARLY_FLATTREE 609 help 610 Select for the Intel CE media processor (CE4100) SOC. 611 This option compiles in support for the CE4100 SOC for settop 612 boxes and media devices. 613 614config X86_INTEL_MID 615 bool "Intel MID platform support" 616 depends on X86_EXTENDED_PLATFORM 617 depends on X86_PLATFORM_DEVICES 618 depends on PCI 619 depends on X86_64 || (PCI_GOANY && X86_32) 620 depends on X86_IO_APIC 621 select I2C 622 select DW_APB_TIMER 623 select INTEL_SCU_PCI 624 help 625 Select to build a kernel capable of supporting Intel MID (Mobile 626 Internet Device) platform systems which do not have the PCI legacy 627 interfaces. If you are building for a PC class system say N here. 628 629 Intel MID platforms are based on an Intel processor and chipset which 630 consume less power than most of the x86 derivatives. 631 632config X86_INTEL_QUARK 633 bool "Intel Quark platform support" 634 depends on X86_32 635 depends on X86_EXTENDED_PLATFORM 636 depends on X86_PLATFORM_DEVICES 637 depends on X86_TSC 638 depends on PCI 639 depends on PCI_GOANY 640 depends on X86_IO_APIC 641 select IOSF_MBI 642 select INTEL_IMR 643 select COMMON_CLK 644 help 645 Select to include support for Quark X1000 SoC. 646 Say Y here if you have a Quark based system such as the Arduino 647 compatible Intel Galileo. 648 649config X86_INTEL_LPSS 650 bool "Intel Low Power Subsystem Support" 651 depends on X86 && ACPI && PCI 652 select COMMON_CLK 653 select PINCTRL 654 select IOSF_MBI 655 help 656 Select to build support for Intel Low Power Subsystem such as 657 found on Intel Lynxpoint PCH. Selecting this option enables 658 things like clock tree (common clock framework) and pincontrol 659 which are needed by the LPSS peripheral drivers. 660 661config X86_AMD_PLATFORM_DEVICE 662 bool "AMD ACPI2Platform devices support" 663 depends on ACPI 664 select COMMON_CLK 665 select PINCTRL 666 help 667 Select to interpret AMD specific ACPI device to platform device 668 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 669 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 670 implemented under PINCTRL subsystem. 671 672config IOSF_MBI 673 tristate "Intel SoC IOSF Sideband support for SoC platforms" 674 depends on PCI 675 help 676 This option enables sideband register access support for Intel SoC 677 platforms. On these platforms the IOSF sideband is used in lieu of 678 MSR's for some register accesses, mostly but not limited to thermal 679 and power. Drivers may query the availability of this device to 680 determine if they need the sideband in order to work on these 681 platforms. The sideband is available on the following SoC products. 682 This list is not meant to be exclusive. 683 - BayTrail 684 - Braswell 685 - Quark 686 687 You should say Y if you are running a kernel on one of these SoC's. 688 689config IOSF_MBI_DEBUG 690 bool "Enable IOSF sideband access through debugfs" 691 depends on IOSF_MBI && DEBUG_FS 692 help 693 Select this option to expose the IOSF sideband access registers (MCR, 694 MDR, MCRX) through debugfs to write and read register information from 695 different units on the SoC. This is most useful for obtaining device 696 state information for debug and analysis. As this is a general access 697 mechanism, users of this option would have specific knowledge of the 698 device they want to access. 699 700 If you don't require the option or are in doubt, say N. 701 702config X86_RDC321X 703 bool "RDC R-321x SoC" 704 depends on X86_32 705 depends on X86_EXTENDED_PLATFORM 706 select M486 707 select X86_REBOOTFIXUPS 708 help 709 This option is needed for RDC R-321x system-on-chip, also known 710 as R-8610-(G). 711 If you don't have one of these chips, you should say N here. 712 713config X86_32_NON_STANDARD 714 bool "Support non-standard 32-bit SMP architectures" 715 depends on X86_32 && SMP 716 depends on X86_EXTENDED_PLATFORM 717 help 718 This option compiles in the bigsmp and STA2X11 default 719 subarchitectures. It is intended for a generic binary 720 kernel. If you select them all, kernel will probe it one by 721 one and will fallback to default. 722 723# Alphabetically sorted list of Non standard 32 bit platforms 724 725config X86_SUPPORTS_MEMORY_FAILURE 726 def_bool y 727 # MCE code calls memory_failure(): 728 depends on X86_MCE 729 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 730 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 731 depends on X86_64 || !SPARSEMEM 732 select ARCH_SUPPORTS_MEMORY_FAILURE 733 734config STA2X11 735 bool "STA2X11 Companion Chip Support" 736 depends on X86_32_NON_STANDARD && PCI 737 select SWIOTLB 738 select MFD_STA2X11 739 select GPIOLIB 740 help 741 This adds support for boards based on the STA2X11 IO-Hub, 742 a.k.a. "ConneXt". The chip is used in place of the standard 743 PC chipset, so all "standard" peripherals are missing. If this 744 option is selected the kernel will still be able to boot on 745 standard PC machines. 746 747config X86_32_IRIS 748 tristate "Eurobraille/Iris poweroff module" 749 depends on X86_32 750 help 751 The Iris machines from EuroBraille do not have APM or ACPI support 752 to shut themselves down properly. A special I/O sequence is 753 needed to do so, which is what this module does at 754 kernel shutdown. 755 756 This is only for Iris machines from EuroBraille. 757 758 If unused, say N. 759 760config SCHED_OMIT_FRAME_POINTER 761 def_bool y 762 prompt "Single-depth WCHAN output" 763 depends on X86 764 help 765 Calculate simpler /proc/<PID>/wchan values. If this option 766 is disabled then wchan values will recurse back to the 767 caller function. This provides more accurate wchan values, 768 at the expense of slightly more scheduling overhead. 769 770 If in doubt, say "Y". 771 772menuconfig HYPERVISOR_GUEST 773 bool "Linux guest support" 774 help 775 Say Y here to enable options for running Linux under various hyper- 776 visors. This option enables basic hypervisor detection and platform 777 setup. 778 779 If you say N, all options in this submenu will be skipped and 780 disabled, and Linux guest support won't be built in. 781 782if HYPERVISOR_GUEST 783 784config PARAVIRT 785 bool "Enable paravirtualization code" 786 depends on HAVE_STATIC_CALL 787 help 788 This changes the kernel so it can modify itself when it is run 789 under a hypervisor, potentially improving performance significantly 790 over full virtualization. However, when run without a hypervisor 791 the kernel is theoretically slower and slightly larger. 792 793config PARAVIRT_XXL 794 bool 795 796config PARAVIRT_DEBUG 797 bool "paravirt-ops debugging" 798 depends on PARAVIRT && DEBUG_KERNEL 799 help 800 Enable to debug paravirt_ops internals. Specifically, BUG if 801 a paravirt_op is missing when it is called. 802 803config PARAVIRT_SPINLOCKS 804 bool "Paravirtualization layer for spinlocks" 805 depends on PARAVIRT && SMP 806 help 807 Paravirtualized spinlocks allow a pvops backend to replace the 808 spinlock implementation with something virtualization-friendly 809 (for example, block the virtual CPU rather than spinning). 810 811 It has a minimal impact on native kernels and gives a nice performance 812 benefit on paravirtualized KVM / Xen kernels. 813 814 If you are unsure how to answer this question, answer Y. 815 816config X86_HV_CALLBACK_VECTOR 817 def_bool n 818 819source "arch/x86/xen/Kconfig" 820 821config KVM_GUEST 822 bool "KVM Guest support (including kvmclock)" 823 depends on PARAVIRT 824 select PARAVIRT_CLOCK 825 select ARCH_CPUIDLE_HALTPOLL 826 select X86_HV_CALLBACK_VECTOR 827 default y 828 help 829 This option enables various optimizations for running under the KVM 830 hypervisor. It includes a paravirtualized clock, so that instead 831 of relying on a PIT (or probably other) emulation by the 832 underlying device model, the host provides the guest with 833 timing infrastructure such as time of day, and system time 834 835config ARCH_CPUIDLE_HALTPOLL 836 def_bool n 837 prompt "Disable host haltpoll when loading haltpoll driver" 838 help 839 If virtualized under KVM, disable host haltpoll. 840 841config PVH 842 bool "Support for running PVH guests" 843 help 844 This option enables the PVH entry point for guest virtual machines 845 as specified in the x86/HVM direct boot ABI. 846 847config PARAVIRT_TIME_ACCOUNTING 848 bool "Paravirtual steal time accounting" 849 depends on PARAVIRT 850 help 851 Select this option to enable fine granularity task steal time 852 accounting. Time spent executing other tasks in parallel with 853 the current vCPU is discounted from the vCPU power. To account for 854 that, there can be a small performance impact. 855 856 If in doubt, say N here. 857 858config PARAVIRT_CLOCK 859 bool 860 861config JAILHOUSE_GUEST 862 bool "Jailhouse non-root cell support" 863 depends on X86_64 && PCI 864 select X86_PM_TIMER 865 help 866 This option allows to run Linux as guest in a Jailhouse non-root 867 cell. You can leave this option disabled if you only want to start 868 Jailhouse and run Linux afterwards in the root cell. 869 870config ACRN_GUEST 871 bool "ACRN Guest support" 872 depends on X86_64 873 select X86_HV_CALLBACK_VECTOR 874 help 875 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 876 a flexible, lightweight reference open-source hypervisor, built with 877 real-time and safety-criticality in mind. It is built for embedded 878 IOT with small footprint and real-time features. More details can be 879 found in https://projectacrn.org/. 880 881endif #HYPERVISOR_GUEST 882 883source "arch/x86/Kconfig.cpu" 884 885config HPET_TIMER 886 def_bool X86_64 887 prompt "HPET Timer Support" if X86_32 888 help 889 Use the IA-PC HPET (High Precision Event Timer) to manage 890 time in preference to the PIT and RTC, if a HPET is 891 present. 892 HPET is the next generation timer replacing legacy 8254s. 893 The HPET provides a stable time base on SMP 894 systems, unlike the TSC, but it is more expensive to access, 895 as it is off-chip. The interface used is documented 896 in the HPET spec, revision 1. 897 898 You can safely choose Y here. However, HPET will only be 899 activated if the platform and the BIOS support this feature. 900 Otherwise the 8254 will be used for timing services. 901 902 Choose N to continue using the legacy 8254 timer. 903 904config HPET_EMULATE_RTC 905 def_bool y 906 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 907 908# Mark as expert because too many people got it wrong. 909# The code disables itself when not needed. 910config DMI 911 default y 912 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 913 bool "Enable DMI scanning" if EXPERT 914 help 915 Enabled scanning of DMI to identify machine quirks. Say Y 916 here unless you have verified that your setup is not 917 affected by entries in the DMI blacklist. Required by PNP 918 BIOS code. 919 920config GART_IOMMU 921 bool "Old AMD GART IOMMU support" 922 select DMA_OPS 923 select IOMMU_HELPER 924 select SWIOTLB 925 depends on X86_64 && PCI && AMD_NB 926 help 927 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 928 GART based hardware IOMMUs. 929 930 The GART supports full DMA access for devices with 32-bit access 931 limitations, on systems with more than 3 GB. This is usually needed 932 for USB, sound, many IDE/SATA chipsets and some other devices. 933 934 Newer systems typically have a modern AMD IOMMU, supported via 935 the CONFIG_AMD_IOMMU=y config option. 936 937 In normal configurations this driver is only active when needed: 938 there's more than 3 GB of memory and the system contains a 939 32-bit limited device. 940 941 If unsure, say Y. 942 943config BOOT_VESA_SUPPORT 944 bool 945 help 946 If true, at least one selected framebuffer driver can take advantage 947 of VESA video modes set at an early boot stage via the vga= parameter. 948 949config MAXSMP 950 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 951 depends on X86_64 && SMP && DEBUG_KERNEL 952 select CPUMASK_OFFSTACK 953 help 954 Enable maximum number of CPUS and NUMA Nodes for this architecture. 955 If unsure, say N. 956 957# 958# The maximum number of CPUs supported: 959# 960# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 961# and which can be configured interactively in the 962# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 963# 964# The ranges are different on 32-bit and 64-bit kernels, depending on 965# hardware capabilities and scalability features of the kernel. 966# 967# ( If MAXSMP is enabled we just use the highest possible value and disable 968# interactive configuration. ) 969# 970 971config NR_CPUS_RANGE_BEGIN 972 int 973 default NR_CPUS_RANGE_END if MAXSMP 974 default 1 if !SMP 975 default 2 976 977config NR_CPUS_RANGE_END 978 int 979 depends on X86_32 980 default 64 if SMP && X86_BIGSMP 981 default 8 if SMP && !X86_BIGSMP 982 default 1 if !SMP 983 984config NR_CPUS_RANGE_END 985 int 986 depends on X86_64 987 default 8192 if SMP && CPUMASK_OFFSTACK 988 default 512 if SMP && !CPUMASK_OFFSTACK 989 default 1 if !SMP 990 991config NR_CPUS_DEFAULT 992 int 993 depends on X86_32 994 default 32 if X86_BIGSMP 995 default 8 if SMP 996 default 1 if !SMP 997 998config NR_CPUS_DEFAULT 999 int 1000 depends on X86_64 1001 default 8192 if MAXSMP 1002 default 64 if SMP 1003 default 1 if !SMP 1004 1005config NR_CPUS 1006 int "Maximum number of CPUs" if SMP && !MAXSMP 1007 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1008 default NR_CPUS_DEFAULT 1009 help 1010 This allows you to specify the maximum number of CPUs which this 1011 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1012 supported value is 8192, otherwise the maximum value is 512. The 1013 minimum value which makes sense is 2. 1014 1015 This is purely to save memory: each supported CPU adds about 8KB 1016 to the kernel image. 1017 1018config SCHED_CLUSTER 1019 bool "Cluster scheduler support" 1020 depends on SMP 1021 default y 1022 help 1023 Cluster scheduler support improves the CPU scheduler's decision 1024 making when dealing with machines that have clusters of CPUs. 1025 Cluster usually means a couple of CPUs which are placed closely 1026 by sharing mid-level caches, last-level cache tags or internal 1027 busses. 1028 1029config SCHED_SMT 1030 def_bool y if SMP 1031 1032config SCHED_MC 1033 def_bool y 1034 prompt "Multi-core scheduler support" 1035 depends on SMP 1036 help 1037 Multi-core scheduler support improves the CPU scheduler's decision 1038 making when dealing with multi-core CPU chips at a cost of slightly 1039 increased overhead in some places. If unsure say N here. 1040 1041config SCHED_MC_PRIO 1042 bool "CPU core priorities scheduler support" 1043 depends on SCHED_MC && CPU_SUP_INTEL 1044 select X86_INTEL_PSTATE 1045 select CPU_FREQ 1046 default y 1047 help 1048 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1049 core ordering determined at manufacturing time, which allows 1050 certain cores to reach higher turbo frequencies (when running 1051 single threaded workloads) than others. 1052 1053 Enabling this kernel feature teaches the scheduler about 1054 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1055 scheduler's CPU selection logic accordingly, so that higher 1056 overall system performance can be achieved. 1057 1058 This feature will have no effect on CPUs without this feature. 1059 1060 If unsure say Y here. 1061 1062config UP_LATE_INIT 1063 def_bool y 1064 depends on !SMP && X86_LOCAL_APIC 1065 1066config X86_UP_APIC 1067 bool "Local APIC support on uniprocessors" if !PCI_MSI 1068 default PCI_MSI 1069 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1070 help 1071 A local APIC (Advanced Programmable Interrupt Controller) is an 1072 integrated interrupt controller in the CPU. If you have a single-CPU 1073 system which has a processor with a local APIC, you can say Y here to 1074 enable and use it. If you say Y here even though your machine doesn't 1075 have a local APIC, then the kernel will still run with no slowdown at 1076 all. The local APIC supports CPU-generated self-interrupts (timer, 1077 performance counters), and the NMI watchdog which detects hard 1078 lockups. 1079 1080config X86_UP_IOAPIC 1081 bool "IO-APIC support on uniprocessors" 1082 depends on X86_UP_APIC 1083 help 1084 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1085 SMP-capable replacement for PC-style interrupt controllers. Most 1086 SMP systems and many recent uniprocessor systems have one. 1087 1088 If you have a single-CPU system with an IO-APIC, you can say Y here 1089 to use it. If you say Y here even though your machine doesn't have 1090 an IO-APIC, then the kernel will still run with no slowdown at all. 1091 1092config X86_LOCAL_APIC 1093 def_bool y 1094 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1095 select IRQ_DOMAIN_HIERARCHY 1096 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1097 1098config X86_IO_APIC 1099 def_bool y 1100 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1101 1102config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1103 bool "Reroute for broken boot IRQs" 1104 depends on X86_IO_APIC 1105 help 1106 This option enables a workaround that fixes a source of 1107 spurious interrupts. This is recommended when threaded 1108 interrupt handling is used on systems where the generation of 1109 superfluous "boot interrupts" cannot be disabled. 1110 1111 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1112 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1113 kernel does during interrupt handling). On chipsets where this 1114 boot IRQ generation cannot be disabled, this workaround keeps 1115 the original IRQ line masked so that only the equivalent "boot 1116 IRQ" is delivered to the CPUs. The workaround also tells the 1117 kernel to set up the IRQ handler on the boot IRQ line. In this 1118 way only one interrupt is delivered to the kernel. Otherwise 1119 the spurious second interrupt may cause the kernel to bring 1120 down (vital) interrupt lines. 1121 1122 Only affects "broken" chipsets. Interrupt sharing may be 1123 increased on these systems. 1124 1125config X86_MCE 1126 bool "Machine Check / overheating reporting" 1127 select GENERIC_ALLOCATOR 1128 default y 1129 help 1130 Machine Check support allows the processor to notify the 1131 kernel if it detects a problem (e.g. overheating, data corruption). 1132 The action the kernel takes depends on the severity of the problem, 1133 ranging from warning messages to halting the machine. 1134 1135config X86_MCELOG_LEGACY 1136 bool "Support for deprecated /dev/mcelog character device" 1137 depends on X86_MCE 1138 help 1139 Enable support for /dev/mcelog which is needed by the old mcelog 1140 userspace logging daemon. Consider switching to the new generation 1141 rasdaemon solution. 1142 1143config X86_MCE_INTEL 1144 def_bool y 1145 prompt "Intel MCE features" 1146 depends on X86_MCE && X86_LOCAL_APIC 1147 help 1148 Additional support for intel specific MCE features such as 1149 the thermal monitor. 1150 1151config X86_MCE_AMD 1152 def_bool y 1153 prompt "AMD MCE features" 1154 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1155 help 1156 Additional support for AMD specific MCE features such as 1157 the DRAM Error Threshold. 1158 1159config X86_ANCIENT_MCE 1160 bool "Support for old Pentium 5 / WinChip machine checks" 1161 depends on X86_32 && X86_MCE 1162 help 1163 Include support for machine check handling on old Pentium 5 or WinChip 1164 systems. These typically need to be enabled explicitly on the command 1165 line. 1166 1167config X86_MCE_THRESHOLD 1168 depends on X86_MCE_AMD || X86_MCE_INTEL 1169 def_bool y 1170 1171config X86_MCE_INJECT 1172 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1173 tristate "Machine check injector support" 1174 help 1175 Provide support for injecting machine checks for testing purposes. 1176 If you don't know what a machine check is and you don't do kernel 1177 QA it is safe to say n. 1178 1179source "arch/x86/events/Kconfig" 1180 1181config X86_LEGACY_VM86 1182 bool "Legacy VM86 support" 1183 depends on X86_32 1184 help 1185 This option allows user programs to put the CPU into V8086 1186 mode, which is an 80286-era approximation of 16-bit real mode. 1187 1188 Some very old versions of X and/or vbetool require this option 1189 for user mode setting. Similarly, DOSEMU will use it if 1190 available to accelerate real mode DOS programs. However, any 1191 recent version of DOSEMU, X, or vbetool should be fully 1192 functional even without kernel VM86 support, as they will all 1193 fall back to software emulation. Nevertheless, if you are using 1194 a 16-bit DOS program where 16-bit performance matters, vm86 1195 mode might be faster than emulation and you might want to 1196 enable this option. 1197 1198 Note that any app that works on a 64-bit kernel is unlikely to 1199 need this option, as 64-bit kernels don't, and can't, support 1200 V8086 mode. This option is also unrelated to 16-bit protected 1201 mode and is not needed to run most 16-bit programs under Wine. 1202 1203 Enabling this option increases the complexity of the kernel 1204 and slows down exception handling a tiny bit. 1205 1206 If unsure, say N here. 1207 1208config VM86 1209 bool 1210 default X86_LEGACY_VM86 1211 1212config X86_16BIT 1213 bool "Enable support for 16-bit segments" if EXPERT 1214 default y 1215 depends on MODIFY_LDT_SYSCALL 1216 help 1217 This option is required by programs like Wine to run 16-bit 1218 protected mode legacy code on x86 processors. Disabling 1219 this option saves about 300 bytes on i386, or around 6K text 1220 plus 16K runtime memory on x86-64, 1221 1222config X86_ESPFIX32 1223 def_bool y 1224 depends on X86_16BIT && X86_32 1225 1226config X86_ESPFIX64 1227 def_bool y 1228 depends on X86_16BIT && X86_64 1229 1230config X86_VSYSCALL_EMULATION 1231 bool "Enable vsyscall emulation" if EXPERT 1232 default y 1233 depends on X86_64 1234 help 1235 This enables emulation of the legacy vsyscall page. Disabling 1236 it is roughly equivalent to booting with vsyscall=none, except 1237 that it will also disable the helpful warning if a program 1238 tries to use a vsyscall. With this option set to N, offending 1239 programs will just segfault, citing addresses of the form 1240 0xffffffffff600?00. 1241 1242 This option is required by many programs built before 2013, and 1243 care should be used even with newer programs if set to N. 1244 1245 Disabling this option saves about 7K of kernel size and 1246 possibly 4K of additional runtime pagetable memory. 1247 1248config X86_IOPL_IOPERM 1249 bool "IOPERM and IOPL Emulation" 1250 default y 1251 help 1252 This enables the ioperm() and iopl() syscalls which are necessary 1253 for legacy applications. 1254 1255 Legacy IOPL support is an overbroad mechanism which allows user 1256 space aside of accessing all 65536 I/O ports also to disable 1257 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1258 capabilities and permission from potentially active security 1259 modules. 1260 1261 The emulation restricts the functionality of the syscall to 1262 only allowing the full range I/O port access, but prevents the 1263 ability to disable interrupts from user space which would be 1264 granted if the hardware IOPL mechanism would be used. 1265 1266config TOSHIBA 1267 tristate "Toshiba Laptop support" 1268 depends on X86_32 1269 help 1270 This adds a driver to safely access the System Management Mode of 1271 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1272 not work on models with a Phoenix BIOS. The System Management Mode 1273 is used to set the BIOS and power saving options on Toshiba portables. 1274 1275 For information on utilities to make use of this driver see the 1276 Toshiba Linux utilities web site at: 1277 <http://www.buzzard.org.uk/toshiba/>. 1278 1279 Say Y if you intend to run this kernel on a Toshiba portable. 1280 Say N otherwise. 1281 1282config X86_REBOOTFIXUPS 1283 bool "Enable X86 board specific fixups for reboot" 1284 depends on X86_32 1285 help 1286 This enables chipset and/or board specific fixups to be done 1287 in order to get reboot to work correctly. This is only needed on 1288 some combinations of hardware and BIOS. The symptom, for which 1289 this config is intended, is when reboot ends with a stalled/hung 1290 system. 1291 1292 Currently, the only fixup is for the Geode machines using 1293 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1294 1295 Say Y if you want to enable the fixup. Currently, it's safe to 1296 enable this option even if you don't need it. 1297 Say N otherwise. 1298 1299config MICROCODE 1300 bool "CPU microcode loading support" 1301 default y 1302 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1303 help 1304 If you say Y here, you will be able to update the microcode on 1305 Intel and AMD processors. The Intel support is for the IA32 family, 1306 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1307 AMD support is for families 0x10 and later. You will obviously need 1308 the actual microcode binary data itself which is not shipped with 1309 the Linux kernel. 1310 1311 The preferred method to load microcode from a detached initrd is described 1312 in Documentation/x86/microcode.rst. For that you need to enable 1313 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1314 initrd for microcode blobs. 1315 1316 In addition, you can build the microcode into the kernel. For that you 1317 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1318 config option. 1319 1320config MICROCODE_INTEL 1321 bool "Intel microcode loading support" 1322 depends on MICROCODE 1323 default MICROCODE 1324 help 1325 This options enables microcode patch loading support for Intel 1326 processors. 1327 1328 For the current Intel microcode data package go to 1329 <https://downloadcenter.intel.com> and search for 1330 'Linux Processor Microcode Data File'. 1331 1332config MICROCODE_AMD 1333 bool "AMD microcode loading support" 1334 depends on MICROCODE 1335 help 1336 If you select this option, microcode patch loading support for AMD 1337 processors will be enabled. 1338 1339config MICROCODE_OLD_INTERFACE 1340 bool "Ancient loading interface (DEPRECATED)" 1341 default n 1342 depends on MICROCODE 1343 help 1344 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1345 which was used by userspace tools like iucode_tool and microcode.ctl. 1346 It is inadequate because it runs too late to be able to properly 1347 load microcode on a machine and it needs special tools. Instead, you 1348 should've switched to the early loading method with the initrd or 1349 builtin microcode by now: Documentation/x86/microcode.rst 1350 1351config X86_MSR 1352 tristate "/dev/cpu/*/msr - Model-specific register support" 1353 help 1354 This device gives privileged processes access to the x86 1355 Model-Specific Registers (MSRs). It is a character device with 1356 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1357 MSR accesses are directed to a specific CPU on multi-processor 1358 systems. 1359 1360config X86_CPUID 1361 tristate "/dev/cpu/*/cpuid - CPU information support" 1362 help 1363 This device gives processes access to the x86 CPUID instruction to 1364 be executed on a specific processor. It is a character device 1365 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1366 /dev/cpu/31/cpuid. 1367 1368choice 1369 prompt "High Memory Support" 1370 default HIGHMEM4G 1371 depends on X86_32 1372 1373config NOHIGHMEM 1374 bool "off" 1375 help 1376 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1377 However, the address space of 32-bit x86 processors is only 4 1378 Gigabytes large. That means that, if you have a large amount of 1379 physical memory, not all of it can be "permanently mapped" by the 1380 kernel. The physical memory that's not permanently mapped is called 1381 "high memory". 1382 1383 If you are compiling a kernel which will never run on a machine with 1384 more than 1 Gigabyte total physical RAM, answer "off" here (default 1385 choice and suitable for most users). This will result in a "3GB/1GB" 1386 split: 3GB are mapped so that each process sees a 3GB virtual memory 1387 space and the remaining part of the 4GB virtual memory space is used 1388 by the kernel to permanently map as much physical memory as 1389 possible. 1390 1391 If the machine has between 1 and 4 Gigabytes physical RAM, then 1392 answer "4GB" here. 1393 1394 If more than 4 Gigabytes is used then answer "64GB" here. This 1395 selection turns Intel PAE (Physical Address Extension) mode on. 1396 PAE implements 3-level paging on IA32 processors. PAE is fully 1397 supported by Linux, PAE mode is implemented on all recent Intel 1398 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1399 then the kernel will not boot on CPUs that don't support PAE! 1400 1401 The actual amount of total physical memory will either be 1402 auto detected or can be forced by using a kernel command line option 1403 such as "mem=256M". (Try "man bootparam" or see the documentation of 1404 your boot loader (lilo or loadlin) about how to pass options to the 1405 kernel at boot time.) 1406 1407 If unsure, say "off". 1408 1409config HIGHMEM4G 1410 bool "4GB" 1411 help 1412 Select this if you have a 32-bit processor and between 1 and 4 1413 gigabytes of physical RAM. 1414 1415config HIGHMEM64G 1416 bool "64GB" 1417 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1418 select X86_PAE 1419 help 1420 Select this if you have a 32-bit processor and more than 4 1421 gigabytes of physical RAM. 1422 1423endchoice 1424 1425choice 1426 prompt "Memory split" if EXPERT 1427 default VMSPLIT_3G 1428 depends on X86_32 1429 help 1430 Select the desired split between kernel and user memory. 1431 1432 If the address range available to the kernel is less than the 1433 physical memory installed, the remaining memory will be available 1434 as "high memory". Accessing high memory is a little more costly 1435 than low memory, as it needs to be mapped into the kernel first. 1436 Note that increasing the kernel address space limits the range 1437 available to user programs, making the address space there 1438 tighter. Selecting anything other than the default 3G/1G split 1439 will also likely make your kernel incompatible with binary-only 1440 kernel modules. 1441 1442 If you are not absolutely sure what you are doing, leave this 1443 option alone! 1444 1445 config VMSPLIT_3G 1446 bool "3G/1G user/kernel split" 1447 config VMSPLIT_3G_OPT 1448 depends on !X86_PAE 1449 bool "3G/1G user/kernel split (for full 1G low memory)" 1450 config VMSPLIT_2G 1451 bool "2G/2G user/kernel split" 1452 config VMSPLIT_2G_OPT 1453 depends on !X86_PAE 1454 bool "2G/2G user/kernel split (for full 2G low memory)" 1455 config VMSPLIT_1G 1456 bool "1G/3G user/kernel split" 1457endchoice 1458 1459config PAGE_OFFSET 1460 hex 1461 default 0xB0000000 if VMSPLIT_3G_OPT 1462 default 0x80000000 if VMSPLIT_2G 1463 default 0x78000000 if VMSPLIT_2G_OPT 1464 default 0x40000000 if VMSPLIT_1G 1465 default 0xC0000000 1466 depends on X86_32 1467 1468config HIGHMEM 1469 def_bool y 1470 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1471 1472config X86_PAE 1473 bool "PAE (Physical Address Extension) Support" 1474 depends on X86_32 && !HIGHMEM4G 1475 select PHYS_ADDR_T_64BIT 1476 select SWIOTLB 1477 help 1478 PAE is required for NX support, and furthermore enables 1479 larger swapspace support for non-overcommit purposes. It 1480 has the cost of more pagetable lookup overhead, and also 1481 consumes more pagetable space per process. 1482 1483config X86_5LEVEL 1484 bool "Enable 5-level page tables support" 1485 default y 1486 select DYNAMIC_MEMORY_LAYOUT 1487 select SPARSEMEM_VMEMMAP 1488 depends on X86_64 1489 help 1490 5-level paging enables access to larger address space: 1491 upto 128 PiB of virtual address space and 4 PiB of 1492 physical address space. 1493 1494 It will be supported by future Intel CPUs. 1495 1496 A kernel with the option enabled can be booted on machines that 1497 support 4- or 5-level paging. 1498 1499 See Documentation/x86/x86_64/5level-paging.rst for more 1500 information. 1501 1502 Say N if unsure. 1503 1504config X86_DIRECT_GBPAGES 1505 def_bool y 1506 depends on X86_64 1507 help 1508 Certain kernel features effectively disable kernel 1509 linear 1 GB mappings (even if the CPU otherwise 1510 supports them), so don't confuse the user by printing 1511 that we have them enabled. 1512 1513config X86_CPA_STATISTICS 1514 bool "Enable statistic for Change Page Attribute" 1515 depends on DEBUG_FS 1516 help 1517 Expose statistics about the Change Page Attribute mechanism, which 1518 helps to determine the effectiveness of preserving large and huge 1519 page mappings when mapping protections are changed. 1520 1521config X86_MEM_ENCRYPT 1522 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1523 select DYNAMIC_PHYSICAL_MASK 1524 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 1525 def_bool n 1526 1527config AMD_MEM_ENCRYPT 1528 bool "AMD Secure Memory Encryption (SME) support" 1529 depends on X86_64 && CPU_SUP_AMD 1530 select DMA_COHERENT_POOL 1531 select ARCH_USE_MEMREMAP_PROT 1532 select INSTRUCTION_DECODER 1533 select ARCH_HAS_CC_PLATFORM 1534 select X86_MEM_ENCRYPT 1535 help 1536 Say yes to enable support for the encryption of system memory. 1537 This requires an AMD processor that supports Secure Memory 1538 Encryption (SME). 1539 1540config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1541 bool "Activate AMD Secure Memory Encryption (SME) by default" 1542 depends on AMD_MEM_ENCRYPT 1543 help 1544 Say yes to have system memory encrypted by default if running on 1545 an AMD processor that supports Secure Memory Encryption (SME). 1546 1547 If set to Y, then the encryption of system memory can be 1548 deactivated with the mem_encrypt=off command line option. 1549 1550 If set to N, then the encryption of system memory can be 1551 activated with the mem_encrypt=on command line option. 1552 1553# Common NUMA Features 1554config NUMA 1555 bool "NUMA Memory Allocation and Scheduler Support" 1556 depends on SMP 1557 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1558 default y if X86_BIGSMP 1559 select USE_PERCPU_NUMA_NODE_ID 1560 help 1561 Enable NUMA (Non-Uniform Memory Access) support. 1562 1563 The kernel will try to allocate memory used by a CPU on the 1564 local memory controller of the CPU and add some more 1565 NUMA awareness to the kernel. 1566 1567 For 64-bit this is recommended if the system is Intel Core i7 1568 (or later), AMD Opteron, or EM64T NUMA. 1569 1570 For 32-bit this is only needed if you boot a 32-bit 1571 kernel on a 64-bit NUMA platform. 1572 1573 Otherwise, you should say N. 1574 1575config AMD_NUMA 1576 def_bool y 1577 prompt "Old style AMD Opteron NUMA detection" 1578 depends on X86_64 && NUMA && PCI 1579 help 1580 Enable AMD NUMA node topology detection. You should say Y here if 1581 you have a multi processor AMD system. This uses an old method to 1582 read the NUMA configuration directly from the builtin Northbridge 1583 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1584 which also takes priority if both are compiled in. 1585 1586config X86_64_ACPI_NUMA 1587 def_bool y 1588 prompt "ACPI NUMA detection" 1589 depends on X86_64 && NUMA && ACPI && PCI 1590 select ACPI_NUMA 1591 help 1592 Enable ACPI SRAT based node topology detection. 1593 1594config NUMA_EMU 1595 bool "NUMA emulation" 1596 depends on NUMA 1597 help 1598 Enable NUMA emulation. A flat machine will be split 1599 into virtual nodes when booted with "numa=fake=N", where N is the 1600 number of nodes. This is only useful for debugging. 1601 1602config NODES_SHIFT 1603 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1604 range 1 10 1605 default "10" if MAXSMP 1606 default "6" if X86_64 1607 default "3" 1608 depends on NUMA 1609 help 1610 Specify the maximum number of NUMA Nodes available on the target 1611 system. Increases memory reserved to accommodate various tables. 1612 1613config ARCH_FLATMEM_ENABLE 1614 def_bool y 1615 depends on X86_32 && !NUMA 1616 1617config ARCH_SPARSEMEM_ENABLE 1618 def_bool y 1619 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1620 select SPARSEMEM_STATIC if X86_32 1621 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1622 1623config ARCH_SPARSEMEM_DEFAULT 1624 def_bool X86_64 || (NUMA && X86_32) 1625 1626config ARCH_SELECT_MEMORY_MODEL 1627 def_bool y 1628 depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1629 1630config ARCH_MEMORY_PROBE 1631 bool "Enable sysfs memory/probe interface" 1632 depends on MEMORY_HOTPLUG 1633 help 1634 This option enables a sysfs memory/probe interface for testing. 1635 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1636 If you are unsure how to answer this question, answer N. 1637 1638config ARCH_PROC_KCORE_TEXT 1639 def_bool y 1640 depends on X86_64 && PROC_KCORE 1641 1642config ILLEGAL_POINTER_VALUE 1643 hex 1644 default 0 if X86_32 1645 default 0xdead000000000000 if X86_64 1646 1647config X86_PMEM_LEGACY_DEVICE 1648 bool 1649 1650config X86_PMEM_LEGACY 1651 tristate "Support non-standard NVDIMMs and ADR protected memory" 1652 depends on PHYS_ADDR_T_64BIT 1653 depends on BLK_DEV 1654 select X86_PMEM_LEGACY_DEVICE 1655 select NUMA_KEEP_MEMINFO if NUMA 1656 select LIBNVDIMM 1657 help 1658 Treat memory marked using the non-standard e820 type of 12 as used 1659 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1660 The kernel will offer these regions to the 'pmem' driver so 1661 they can be used for persistent storage. 1662 1663 Say Y if unsure. 1664 1665config HIGHPTE 1666 bool "Allocate 3rd-level pagetables from highmem" 1667 depends on HIGHMEM 1668 help 1669 The VM uses one page table entry for each page of physical memory. 1670 For systems with a lot of RAM, this can be wasteful of precious 1671 low memory. Setting this option will put user-space page table 1672 entries in high memory. 1673 1674config X86_CHECK_BIOS_CORRUPTION 1675 bool "Check for low memory corruption" 1676 help 1677 Periodically check for memory corruption in low memory, which 1678 is suspected to be caused by BIOS. Even when enabled in the 1679 configuration, it is disabled at runtime. Enable it by 1680 setting "memory_corruption_check=1" on the kernel command 1681 line. By default it scans the low 64k of memory every 60 1682 seconds; see the memory_corruption_check_size and 1683 memory_corruption_check_period parameters in 1684 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1685 1686 When enabled with the default parameters, this option has 1687 almost no overhead, as it reserves a relatively small amount 1688 of memory and scans it infrequently. It both detects corruption 1689 and prevents it from affecting the running system. 1690 1691 It is, however, intended as a diagnostic tool; if repeatable 1692 BIOS-originated corruption always affects the same memory, 1693 you can use memmap= to prevent the kernel from using that 1694 memory. 1695 1696config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1697 bool "Set the default setting of memory_corruption_check" 1698 depends on X86_CHECK_BIOS_CORRUPTION 1699 default y 1700 help 1701 Set whether the default state of memory_corruption_check is 1702 on or off. 1703 1704config MATH_EMULATION 1705 bool 1706 depends on MODIFY_LDT_SYSCALL 1707 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1708 help 1709 Linux can emulate a math coprocessor (used for floating point 1710 operations) if you don't have one. 486DX and Pentium processors have 1711 a math coprocessor built in, 486SX and 386 do not, unless you added 1712 a 487DX or 387, respectively. (The messages during boot time can 1713 give you some hints here ["man dmesg"].) Everyone needs either a 1714 coprocessor or this emulation. 1715 1716 If you don't have a math coprocessor, you need to say Y here; if you 1717 say Y here even though you have a coprocessor, the coprocessor will 1718 be used nevertheless. (This behavior can be changed with the kernel 1719 command line option "no387", which comes handy if your coprocessor 1720 is broken. Try "man bootparam" or see the documentation of your boot 1721 loader (lilo or loadlin) about how to pass options to the kernel at 1722 boot time.) This means that it is a good idea to say Y here if you 1723 intend to use this kernel on different machines. 1724 1725 More information about the internals of the Linux math coprocessor 1726 emulation can be found in <file:arch/x86/math-emu/README>. 1727 1728 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1729 kernel, it won't hurt. 1730 1731config MTRR 1732 def_bool y 1733 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1734 help 1735 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1736 the Memory Type Range Registers (MTRRs) may be used to control 1737 processor access to memory ranges. This is most useful if you have 1738 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1739 allows bus write transfers to be combined into a larger transfer 1740 before bursting over the PCI/AGP bus. This can increase performance 1741 of image write operations 2.5 times or more. Saying Y here creates a 1742 /proc/mtrr file which may be used to manipulate your processor's 1743 MTRRs. Typically the X server should use this. 1744 1745 This code has a reasonably generic interface so that similar 1746 control registers on other processors can be easily supported 1747 as well: 1748 1749 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1750 Registers (ARRs) which provide a similar functionality to MTRRs. For 1751 these, the ARRs are used to emulate the MTRRs. 1752 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1753 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1754 write-combining. All of these processors are supported by this code 1755 and it makes sense to say Y here if you have one of them. 1756 1757 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1758 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1759 can lead to all sorts of problems, so it's good to say Y here. 1760 1761 You can safely say Y even if your machine doesn't have MTRRs, you'll 1762 just add about 9 KB to your kernel. 1763 1764 See <file:Documentation/x86/mtrr.rst> for more information. 1765 1766config MTRR_SANITIZER 1767 def_bool y 1768 prompt "MTRR cleanup support" 1769 depends on MTRR 1770 help 1771 Convert MTRR layout from continuous to discrete, so X drivers can 1772 add writeback entries. 1773 1774 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1775 The largest mtrr entry size for a continuous block can be set with 1776 mtrr_chunk_size. 1777 1778 If unsure, say Y. 1779 1780config MTRR_SANITIZER_ENABLE_DEFAULT 1781 int "MTRR cleanup enable value (0-1)" 1782 range 0 1 1783 default "0" 1784 depends on MTRR_SANITIZER 1785 help 1786 Enable mtrr cleanup default value 1787 1788config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1789 int "MTRR cleanup spare reg num (0-7)" 1790 range 0 7 1791 default "1" 1792 depends on MTRR_SANITIZER 1793 help 1794 mtrr cleanup spare entries default, it can be changed via 1795 mtrr_spare_reg_nr=N on the kernel command line. 1796 1797config X86_PAT 1798 def_bool y 1799 prompt "x86 PAT support" if EXPERT 1800 depends on MTRR 1801 help 1802 Use PAT attributes to setup page level cache control. 1803 1804 PATs are the modern equivalents of MTRRs and are much more 1805 flexible than MTRRs. 1806 1807 Say N here if you see bootup problems (boot crash, boot hang, 1808 spontaneous reboots) or a non-working video driver. 1809 1810 If unsure, say Y. 1811 1812config ARCH_USES_PG_UNCACHED 1813 def_bool y 1814 depends on X86_PAT 1815 1816config ARCH_RANDOM 1817 def_bool y 1818 prompt "x86 architectural random number generator" if EXPERT 1819 help 1820 Enable the x86 architectural RDRAND instruction 1821 (Intel Bull Mountain technology) to generate random numbers. 1822 If supported, this is a high bandwidth, cryptographically 1823 secure hardware random number generator. 1824 1825config X86_SMAP 1826 def_bool y 1827 prompt "Supervisor Mode Access Prevention" if EXPERT 1828 help 1829 Supervisor Mode Access Prevention (SMAP) is a security 1830 feature in newer Intel processors. There is a small 1831 performance cost if this enabled and turned on; there is 1832 also a small increase in the kernel size if this is enabled. 1833 1834 If unsure, say Y. 1835 1836config X86_UMIP 1837 def_bool y 1838 prompt "User Mode Instruction Prevention" if EXPERT 1839 help 1840 User Mode Instruction Prevention (UMIP) is a security feature in 1841 some x86 processors. If enabled, a general protection fault is 1842 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1843 executed in user mode. These instructions unnecessarily expose 1844 information about the hardware state. 1845 1846 The vast majority of applications do not use these instructions. 1847 For the very few that do, software emulation is provided in 1848 specific cases in protected and virtual-8086 modes. Emulated 1849 results are dummy. 1850 1851config CC_HAS_IBT 1852 # GCC >= 9 and binutils >= 2.29 1853 # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1854 # Clang/LLVM >= 14 1855 # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1856 # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1857 def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1858 (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1859 $(as-instr,endbr64) 1860 1861config X86_KERNEL_IBT 1862 prompt "Indirect Branch Tracking" 1863 bool 1864 depends on X86_64 && CC_HAS_IBT && STACK_VALIDATION 1865 # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1866 depends on !LD_IS_LLD || LLD_VERSION >= 140000 1867 help 1868 Build the kernel with support for Indirect Branch Tracking, a 1869 hardware support course-grain forward-edge Control Flow Integrity 1870 protection. It enforces that all indirect calls must land on 1871 an ENDBR instruction, as such, the compiler will instrument the 1872 code with them to make this happen. 1873 1874 In addition to building the kernel with IBT, seal all functions that 1875 are not indirect call targets, avoiding them ever becoming one. 1876 1877 This requires LTO like objtool runs and will slow down the build. It 1878 does significantly reduce the number of ENDBR instructions in the 1879 kernel image. 1880 1881config X86_INTEL_MEMORY_PROTECTION_KEYS 1882 prompt "Memory Protection Keys" 1883 def_bool y 1884 # Note: only available in 64-bit mode 1885 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1886 select ARCH_USES_HIGH_VMA_FLAGS 1887 select ARCH_HAS_PKEYS 1888 help 1889 Memory Protection Keys provides a mechanism for enforcing 1890 page-based protections, but without requiring modification of the 1891 page tables when an application changes protection domains. 1892 1893 For details, see Documentation/core-api/protection-keys.rst 1894 1895 If unsure, say y. 1896 1897choice 1898 prompt "TSX enable mode" 1899 depends on CPU_SUP_INTEL 1900 default X86_INTEL_TSX_MODE_OFF 1901 help 1902 Intel's TSX (Transactional Synchronization Extensions) feature 1903 allows to optimize locking protocols through lock elision which 1904 can lead to a noticeable performance boost. 1905 1906 On the other hand it has been shown that TSX can be exploited 1907 to form side channel attacks (e.g. TAA) and chances are there 1908 will be more of those attacks discovered in the future. 1909 1910 Therefore TSX is not enabled by default (aka tsx=off). An admin 1911 might override this decision by tsx=on the command line parameter. 1912 Even with TSX enabled, the kernel will attempt to enable the best 1913 possible TAA mitigation setting depending on the microcode available 1914 for the particular machine. 1915 1916 This option allows to set the default tsx mode between tsx=on, =off 1917 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1918 details. 1919 1920 Say off if not sure, auto if TSX is in use but it should be used on safe 1921 platforms or on if TSX is in use and the security aspect of tsx is not 1922 relevant. 1923 1924config X86_INTEL_TSX_MODE_OFF 1925 bool "off" 1926 help 1927 TSX is disabled if possible - equals to tsx=off command line parameter. 1928 1929config X86_INTEL_TSX_MODE_ON 1930 bool "on" 1931 help 1932 TSX is always enabled on TSX capable HW - equals the tsx=on command 1933 line parameter. 1934 1935config X86_INTEL_TSX_MODE_AUTO 1936 bool "auto" 1937 help 1938 TSX is enabled on TSX capable HW that is believed to be safe against 1939 side channel attacks- equals the tsx=auto command line parameter. 1940endchoice 1941 1942config X86_SGX 1943 bool "Software Guard eXtensions (SGX)" 1944 depends on X86_64 && CPU_SUP_INTEL 1945 depends on CRYPTO=y 1946 depends on CRYPTO_SHA256=y 1947 select SRCU 1948 select MMU_NOTIFIER 1949 select NUMA_KEEP_MEMINFO if NUMA 1950 select XARRAY_MULTI 1951 help 1952 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1953 that can be used by applications to set aside private regions of code 1954 and data, referred to as enclaves. An enclave's private memory can 1955 only be accessed by code running within the enclave. Accesses from 1956 outside the enclave, including other enclaves, are disallowed by 1957 hardware. 1958 1959 If unsure, say N. 1960 1961config EFI 1962 bool "EFI runtime service support" 1963 depends on ACPI 1964 select UCS2_STRING 1965 select EFI_RUNTIME_WRAPPERS 1966 select ARCH_USE_MEMREMAP_PROT 1967 help 1968 This enables the kernel to use EFI runtime services that are 1969 available (such as the EFI variable services). 1970 1971 This option is only useful on systems that have EFI firmware. 1972 In addition, you should use the latest ELILO loader available 1973 at <http://elilo.sourceforge.net> in order to take advantage 1974 of EFI runtime services. However, even with this option, the 1975 resultant kernel should continue to boot on existing non-EFI 1976 platforms. 1977 1978config EFI_STUB 1979 bool "EFI stub support" 1980 depends on EFI 1981 depends on $(cc-option,-mabi=ms) || X86_32 1982 select RELOCATABLE 1983 help 1984 This kernel feature allows a bzImage to be loaded directly 1985 by EFI firmware without the use of a bootloader. 1986 1987 See Documentation/admin-guide/efi-stub.rst for more information. 1988 1989config EFI_MIXED 1990 bool "EFI mixed-mode support" 1991 depends on EFI_STUB && X86_64 1992 help 1993 Enabling this feature allows a 64-bit kernel to be booted 1994 on a 32-bit firmware, provided that your CPU supports 64-bit 1995 mode. 1996 1997 Note that it is not possible to boot a mixed-mode enabled 1998 kernel via the EFI boot stub - a bootloader that supports 1999 the EFI handover protocol must be used. 2000 2001 If unsure, say N. 2002 2003source "kernel/Kconfig.hz" 2004 2005config KEXEC 2006 bool "kexec system call" 2007 select KEXEC_CORE 2008 help 2009 kexec is a system call that implements the ability to shutdown your 2010 current kernel, and to start another kernel. It is like a reboot 2011 but it is independent of the system firmware. And like a reboot 2012 you can start any kernel with it, not just Linux. 2013 2014 The name comes from the similarity to the exec system call. 2015 2016 It is an ongoing process to be certain the hardware in a machine 2017 is properly shutdown, so do not be surprised if this code does not 2018 initially work for you. As of this writing the exact hardware 2019 interface is strongly in flux, so no good recommendation can be 2020 made. 2021 2022config KEXEC_FILE 2023 bool "kexec file based system call" 2024 select KEXEC_CORE 2025 select BUILD_BIN2C 2026 depends on X86_64 2027 depends on CRYPTO=y 2028 depends on CRYPTO_SHA256=y 2029 help 2030 This is new version of kexec system call. This system call is 2031 file based and takes file descriptors as system call argument 2032 for kernel and initramfs as opposed to list of segments as 2033 accepted by previous system call. 2034 2035config ARCH_HAS_KEXEC_PURGATORY 2036 def_bool KEXEC_FILE 2037 2038config KEXEC_SIG 2039 bool "Verify kernel signature during kexec_file_load() syscall" 2040 depends on KEXEC_FILE 2041 help 2042 2043 This option makes the kexec_file_load() syscall check for a valid 2044 signature of the kernel image. The image can still be loaded without 2045 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2046 there's a signature that we can check, then it must be valid. 2047 2048 In addition to this option, you need to enable signature 2049 verification for the corresponding kernel image type being 2050 loaded in order for this to work. 2051 2052config KEXEC_SIG_FORCE 2053 bool "Require a valid signature in kexec_file_load() syscall" 2054 depends on KEXEC_SIG 2055 help 2056 This option makes kernel signature verification mandatory for 2057 the kexec_file_load() syscall. 2058 2059config KEXEC_BZIMAGE_VERIFY_SIG 2060 bool "Enable bzImage signature verification support" 2061 depends on KEXEC_SIG 2062 depends on SIGNED_PE_FILE_VERIFICATION 2063 select SYSTEM_TRUSTED_KEYRING 2064 help 2065 Enable bzImage signature verification support. 2066 2067config CRASH_DUMP 2068 bool "kernel crash dumps" 2069 depends on X86_64 || (X86_32 && HIGHMEM) 2070 help 2071 Generate crash dump after being started by kexec. 2072 This should be normally only set in special crash dump kernels 2073 which are loaded in the main kernel with kexec-tools into 2074 a specially reserved region and then later executed after 2075 a crash by kdump/kexec. The crash dump kernel must be compiled 2076 to a memory address not used by the main kernel or BIOS using 2077 PHYSICAL_START, or it must be built as a relocatable image 2078 (CONFIG_RELOCATABLE=y). 2079 For more details see Documentation/admin-guide/kdump/kdump.rst 2080 2081config KEXEC_JUMP 2082 bool "kexec jump" 2083 depends on KEXEC && HIBERNATION 2084 help 2085 Jump between original kernel and kexeced kernel and invoke 2086 code in physical address mode via KEXEC 2087 2088config PHYSICAL_START 2089 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2090 default "0x1000000" 2091 help 2092 This gives the physical address where the kernel is loaded. 2093 2094 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2095 bzImage will decompress itself to above physical address and 2096 run from there. Otherwise, bzImage will run from the address where 2097 it has been loaded by the boot loader and will ignore above physical 2098 address. 2099 2100 In normal kdump cases one does not have to set/change this option 2101 as now bzImage can be compiled as a completely relocatable image 2102 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2103 address. This option is mainly useful for the folks who don't want 2104 to use a bzImage for capturing the crash dump and want to use a 2105 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2106 to be specifically compiled to run from a specific memory area 2107 (normally a reserved region) and this option comes handy. 2108 2109 So if you are using bzImage for capturing the crash dump, 2110 leave the value here unchanged to 0x1000000 and set 2111 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2112 for capturing the crash dump change this value to start of 2113 the reserved region. In other words, it can be set based on 2114 the "X" value as specified in the "crashkernel=YM@XM" 2115 command line boot parameter passed to the panic-ed 2116 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2117 for more details about crash dumps. 2118 2119 Usage of bzImage for capturing the crash dump is recommended as 2120 one does not have to build two kernels. Same kernel can be used 2121 as production kernel and capture kernel. Above option should have 2122 gone away after relocatable bzImage support is introduced. But it 2123 is present because there are users out there who continue to use 2124 vmlinux for dump capture. This option should go away down the 2125 line. 2126 2127 Don't change this unless you know what you are doing. 2128 2129config RELOCATABLE 2130 bool "Build a relocatable kernel" 2131 default y 2132 help 2133 This builds a kernel image that retains relocation information 2134 so it can be loaded someplace besides the default 1MB. 2135 The relocations tend to make the kernel binary about 10% larger, 2136 but are discarded at runtime. 2137 2138 One use is for the kexec on panic case where the recovery kernel 2139 must live at a different physical address than the primary 2140 kernel. 2141 2142 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2143 it has been loaded at and the compile time physical address 2144 (CONFIG_PHYSICAL_START) is used as the minimum location. 2145 2146config RANDOMIZE_BASE 2147 bool "Randomize the address of the kernel image (KASLR)" 2148 depends on RELOCATABLE 2149 default y 2150 help 2151 In support of Kernel Address Space Layout Randomization (KASLR), 2152 this randomizes the physical address at which the kernel image 2153 is decompressed and the virtual address where the kernel 2154 image is mapped, as a security feature that deters exploit 2155 attempts relying on knowledge of the location of kernel 2156 code internals. 2157 2158 On 64-bit, the kernel physical and virtual addresses are 2159 randomized separately. The physical address will be anywhere 2160 between 16MB and the top of physical memory (up to 64TB). The 2161 virtual address will be randomized from 16MB up to 1GB (9 bits 2162 of entropy). Note that this also reduces the memory space 2163 available to kernel modules from 1.5GB to 1GB. 2164 2165 On 32-bit, the kernel physical and virtual addresses are 2166 randomized together. They will be randomized from 16MB up to 2167 512MB (8 bits of entropy). 2168 2169 Entropy is generated using the RDRAND instruction if it is 2170 supported. If RDTSC is supported, its value is mixed into 2171 the entropy pool as well. If neither RDRAND nor RDTSC are 2172 supported, then entropy is read from the i8254 timer. The 2173 usable entropy is limited by the kernel being built using 2174 2GB addressing, and that PHYSICAL_ALIGN must be at a 2175 minimum of 2MB. As a result, only 10 bits of entropy are 2176 theoretically possible, but the implementations are further 2177 limited due to memory layouts. 2178 2179 If unsure, say Y. 2180 2181# Relocation on x86 needs some additional build support 2182config X86_NEED_RELOCS 2183 def_bool y 2184 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2185 2186config PHYSICAL_ALIGN 2187 hex "Alignment value to which kernel should be aligned" 2188 default "0x200000" 2189 range 0x2000 0x1000000 if X86_32 2190 range 0x200000 0x1000000 if X86_64 2191 help 2192 This value puts the alignment restrictions on physical address 2193 where kernel is loaded and run from. Kernel is compiled for an 2194 address which meets above alignment restriction. 2195 2196 If bootloader loads the kernel at a non-aligned address and 2197 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2198 address aligned to above value and run from there. 2199 2200 If bootloader loads the kernel at a non-aligned address and 2201 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2202 load address and decompress itself to the address it has been 2203 compiled for and run from there. The address for which kernel is 2204 compiled already meets above alignment restrictions. Hence the 2205 end result is that kernel runs from a physical address meeting 2206 above alignment restrictions. 2207 2208 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2209 this value must be a multiple of 0x200000. 2210 2211 Don't change this unless you know what you are doing. 2212 2213config DYNAMIC_MEMORY_LAYOUT 2214 bool 2215 help 2216 This option makes base addresses of vmalloc and vmemmap as well as 2217 __PAGE_OFFSET movable during boot. 2218 2219config RANDOMIZE_MEMORY 2220 bool "Randomize the kernel memory sections" 2221 depends on X86_64 2222 depends on RANDOMIZE_BASE 2223 select DYNAMIC_MEMORY_LAYOUT 2224 default RANDOMIZE_BASE 2225 help 2226 Randomizes the base virtual address of kernel memory sections 2227 (physical memory mapping, vmalloc & vmemmap). This security feature 2228 makes exploits relying on predictable memory locations less reliable. 2229 2230 The order of allocations remains unchanged. Entropy is generated in 2231 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2232 configuration have in average 30,000 different possible virtual 2233 addresses for each memory section. 2234 2235 If unsure, say Y. 2236 2237config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2238 hex "Physical memory mapping padding" if EXPERT 2239 depends on RANDOMIZE_MEMORY 2240 default "0xa" if MEMORY_HOTPLUG 2241 default "0x0" 2242 range 0x1 0x40 if MEMORY_HOTPLUG 2243 range 0x0 0x40 2244 help 2245 Define the padding in terabytes added to the existing physical 2246 memory size during kernel memory randomization. It is useful 2247 for memory hotplug support but reduces the entropy available for 2248 address randomization. 2249 2250 If unsure, leave at the default value. 2251 2252config HOTPLUG_CPU 2253 def_bool y 2254 depends on SMP 2255 2256config BOOTPARAM_HOTPLUG_CPU0 2257 bool "Set default setting of cpu0_hotpluggable" 2258 depends on HOTPLUG_CPU 2259 help 2260 Set whether default state of cpu0_hotpluggable is on or off. 2261 2262 Say Y here to enable CPU0 hotplug by default. If this switch 2263 is turned on, there is no need to give cpu0_hotplug kernel 2264 parameter and the CPU0 hotplug feature is enabled by default. 2265 2266 Please note: there are two known CPU0 dependencies if you want 2267 to enable the CPU0 hotplug feature either by this switch or by 2268 cpu0_hotplug kernel parameter. 2269 2270 First, resume from hibernate or suspend always starts from CPU0. 2271 So hibernate and suspend are prevented if CPU0 is offline. 2272 2273 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2274 offline if any interrupt can not migrate out of CPU0. There may 2275 be other CPU0 dependencies. 2276 2277 Please make sure the dependencies are under your control before 2278 you enable this feature. 2279 2280 Say N if you don't want to enable CPU0 hotplug feature by default. 2281 You still can enable the CPU0 hotplug feature at boot by kernel 2282 parameter cpu0_hotplug. 2283 2284config DEBUG_HOTPLUG_CPU0 2285 def_bool n 2286 prompt "Debug CPU0 hotplug" 2287 depends on HOTPLUG_CPU 2288 help 2289 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2290 soon as possible and boots up userspace with CPU0 offlined. User 2291 can online CPU0 back after boot time. 2292 2293 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2294 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2295 compilation or giving cpu0_hotplug kernel parameter at boot. 2296 2297 If unsure, say N. 2298 2299config COMPAT_VDSO 2300 def_bool n 2301 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2302 depends on COMPAT_32 2303 help 2304 Certain buggy versions of glibc will crash if they are 2305 presented with a 32-bit vDSO that is not mapped at the address 2306 indicated in its segment table. 2307 2308 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2309 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2310 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2311 the only released version with the bug, but OpenSUSE 9 2312 contains a buggy "glibc 2.3.2". 2313 2314 The symptom of the bug is that everything crashes on startup, saying: 2315 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2316 2317 Saying Y here changes the default value of the vdso32 boot 2318 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2319 This works around the glibc bug but hurts performance. 2320 2321 If unsure, say N: if you are compiling your own kernel, you 2322 are unlikely to be using a buggy version of glibc. 2323 2324choice 2325 prompt "vsyscall table for legacy applications" 2326 depends on X86_64 2327 default LEGACY_VSYSCALL_XONLY 2328 help 2329 Legacy user code that does not know how to find the vDSO expects 2330 to be able to issue three syscalls by calling fixed addresses in 2331 kernel space. Since this location is not randomized with ASLR, 2332 it can be used to assist security vulnerability exploitation. 2333 2334 This setting can be changed at boot time via the kernel command 2335 line parameter vsyscall=[emulate|xonly|none]. 2336 2337 On a system with recent enough glibc (2.14 or newer) and no 2338 static binaries, you can say None without a performance penalty 2339 to improve security. 2340 2341 If unsure, select "Emulate execution only". 2342 2343 config LEGACY_VSYSCALL_EMULATE 2344 bool "Full emulation" 2345 help 2346 The kernel traps and emulates calls into the fixed vsyscall 2347 address mapping. This makes the mapping non-executable, but 2348 it still contains readable known contents, which could be 2349 used in certain rare security vulnerability exploits. This 2350 configuration is recommended when using legacy userspace 2351 that still uses vsyscalls along with legacy binary 2352 instrumentation tools that require code to be readable. 2353 2354 An example of this type of legacy userspace is running 2355 Pin on an old binary that still uses vsyscalls. 2356 2357 config LEGACY_VSYSCALL_XONLY 2358 bool "Emulate execution only" 2359 help 2360 The kernel traps and emulates calls into the fixed vsyscall 2361 address mapping and does not allow reads. This 2362 configuration is recommended when userspace might use the 2363 legacy vsyscall area but support for legacy binary 2364 instrumentation of legacy code is not needed. It mitigates 2365 certain uses of the vsyscall area as an ASLR-bypassing 2366 buffer. 2367 2368 config LEGACY_VSYSCALL_NONE 2369 bool "None" 2370 help 2371 There will be no vsyscall mapping at all. This will 2372 eliminate any risk of ASLR bypass due to the vsyscall 2373 fixed address mapping. Attempts to use the vsyscalls 2374 will be reported to dmesg, so that either old or 2375 malicious userspace programs can be identified. 2376 2377endchoice 2378 2379config CMDLINE_BOOL 2380 bool "Built-in kernel command line" 2381 help 2382 Allow for specifying boot arguments to the kernel at 2383 build time. On some systems (e.g. embedded ones), it is 2384 necessary or convenient to provide some or all of the 2385 kernel boot arguments with the kernel itself (that is, 2386 to not rely on the boot loader to provide them.) 2387 2388 To compile command line arguments into the kernel, 2389 set this option to 'Y', then fill in the 2390 boot arguments in CONFIG_CMDLINE. 2391 2392 Systems with fully functional boot loaders (i.e. non-embedded) 2393 should leave this option set to 'N'. 2394 2395config CMDLINE 2396 string "Built-in kernel command string" 2397 depends on CMDLINE_BOOL 2398 default "" 2399 help 2400 Enter arguments here that should be compiled into the kernel 2401 image and used at boot time. If the boot loader provides a 2402 command line at boot time, it is appended to this string to 2403 form the full kernel command line, when the system boots. 2404 2405 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2406 change this behavior. 2407 2408 In most cases, the command line (whether built-in or provided 2409 by the boot loader) should specify the device for the root 2410 file system. 2411 2412config CMDLINE_OVERRIDE 2413 bool "Built-in command line overrides boot loader arguments" 2414 depends on CMDLINE_BOOL && CMDLINE != "" 2415 help 2416 Set this option to 'Y' to have the kernel ignore the boot loader 2417 command line, and use ONLY the built-in command line. 2418 2419 This is used to work around broken boot loaders. This should 2420 be set to 'N' under normal conditions. 2421 2422config MODIFY_LDT_SYSCALL 2423 bool "Enable the LDT (local descriptor table)" if EXPERT 2424 default y 2425 help 2426 Linux can allow user programs to install a per-process x86 2427 Local Descriptor Table (LDT) using the modify_ldt(2) system 2428 call. This is required to run 16-bit or segmented code such as 2429 DOSEMU or some Wine programs. It is also used by some very old 2430 threading libraries. 2431 2432 Enabling this feature adds a small amount of overhead to 2433 context switches and increases the low-level kernel attack 2434 surface. Disabling it removes the modify_ldt(2) system call. 2435 2436 Saying 'N' here may make sense for embedded or server kernels. 2437 2438config STRICT_SIGALTSTACK_SIZE 2439 bool "Enforce strict size checking for sigaltstack" 2440 depends on DYNAMIC_SIGFRAME 2441 help 2442 For historical reasons MINSIGSTKSZ is a constant which became 2443 already too small with AVX512 support. Add a mechanism to 2444 enforce strict checking of the sigaltstack size against the 2445 real size of the FPU frame. This option enables the check 2446 by default. It can also be controlled via the kernel command 2447 line option 'strict_sas_size' independent of this config 2448 switch. Enabling it might break existing applications which 2449 allocate a too small sigaltstack but 'work' because they 2450 never get a signal delivered. 2451 2452 Say 'N' unless you want to really enforce this check. 2453 2454source "kernel/livepatch/Kconfig" 2455 2456endmenu 2457 2458config ARCH_HAS_ADD_PAGES 2459 def_bool y 2460 depends on ARCH_ENABLE_MEMORY_HOTPLUG 2461 2462config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2463 def_bool y 2464 2465menu "Power management and ACPI options" 2466 2467config ARCH_HIBERNATION_HEADER 2468 def_bool y 2469 depends on HIBERNATION 2470 2471source "kernel/power/Kconfig" 2472 2473source "drivers/acpi/Kconfig" 2474 2475config X86_APM_BOOT 2476 def_bool y 2477 depends on APM 2478 2479menuconfig APM 2480 tristate "APM (Advanced Power Management) BIOS support" 2481 depends on X86_32 && PM_SLEEP 2482 help 2483 APM is a BIOS specification for saving power using several different 2484 techniques. This is mostly useful for battery powered laptops with 2485 APM compliant BIOSes. If you say Y here, the system time will be 2486 reset after a RESUME operation, the /proc/apm device will provide 2487 battery status information, and user-space programs will receive 2488 notification of APM "events" (e.g. battery status change). 2489 2490 If you select "Y" here, you can disable actual use of the APM 2491 BIOS by passing the "apm=off" option to the kernel at boot time. 2492 2493 Note that the APM support is almost completely disabled for 2494 machines with more than one CPU. 2495 2496 In order to use APM, you will need supporting software. For location 2497 and more information, read <file:Documentation/power/apm-acpi.rst> 2498 and the Battery Powered Linux mini-HOWTO, available from 2499 <http://www.tldp.org/docs.html#howto>. 2500 2501 This driver does not spin down disk drives (see the hdparm(8) 2502 manpage ("man 8 hdparm") for that), and it doesn't turn off 2503 VESA-compliant "green" monitors. 2504 2505 This driver does not support the TI 4000M TravelMate and the ACER 2506 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2507 desktop machines also don't have compliant BIOSes, and this driver 2508 may cause those machines to panic during the boot phase. 2509 2510 Generally, if you don't have a battery in your machine, there isn't 2511 much point in using this driver and you should say N. If you get 2512 random kernel OOPSes or reboots that don't seem to be related to 2513 anything, try disabling/enabling this option (or disabling/enabling 2514 APM in your BIOS). 2515 2516 Some other things you should try when experiencing seemingly random, 2517 "weird" problems: 2518 2519 1) make sure that you have enough swap space and that it is 2520 enabled. 2521 2) pass the "no-hlt" option to the kernel 2522 3) switch on floating point emulation in the kernel and pass 2523 the "no387" option to the kernel 2524 4) pass the "floppy=nodma" option to the kernel 2525 5) pass the "mem=4M" option to the kernel (thereby disabling 2526 all but the first 4 MB of RAM) 2527 6) make sure that the CPU is not over clocked. 2528 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2529 8) disable the cache from your BIOS settings 2530 9) install a fan for the video card or exchange video RAM 2531 10) install a better fan for the CPU 2532 11) exchange RAM chips 2533 12) exchange the motherboard. 2534 2535 To compile this driver as a module, choose M here: the 2536 module will be called apm. 2537 2538if APM 2539 2540config APM_IGNORE_USER_SUSPEND 2541 bool "Ignore USER SUSPEND" 2542 help 2543 This option will ignore USER SUSPEND requests. On machines with a 2544 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2545 series notebooks, it is necessary to say Y because of a BIOS bug. 2546 2547config APM_DO_ENABLE 2548 bool "Enable PM at boot time" 2549 help 2550 Enable APM features at boot time. From page 36 of the APM BIOS 2551 specification: "When disabled, the APM BIOS does not automatically 2552 power manage devices, enter the Standby State, enter the Suspend 2553 State, or take power saving steps in response to CPU Idle calls." 2554 This driver will make CPU Idle calls when Linux is idle (unless this 2555 feature is turned off -- see "Do CPU IDLE calls", below). This 2556 should always save battery power, but more complicated APM features 2557 will be dependent on your BIOS implementation. You may need to turn 2558 this option off if your computer hangs at boot time when using APM 2559 support, or if it beeps continuously instead of suspending. Turn 2560 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2561 T400CDT. This is off by default since most machines do fine without 2562 this feature. 2563 2564config APM_CPU_IDLE 2565 depends on CPU_IDLE 2566 bool "Make CPU Idle calls when idle" 2567 help 2568 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2569 On some machines, this can activate improved power savings, such as 2570 a slowed CPU clock rate, when the machine is idle. These idle calls 2571 are made after the idle loop has run for some length of time (e.g., 2572 333 mS). On some machines, this will cause a hang at boot time or 2573 whenever the CPU becomes idle. (On machines with more than one CPU, 2574 this option does nothing.) 2575 2576config APM_DISPLAY_BLANK 2577 bool "Enable console blanking using APM" 2578 help 2579 Enable console blanking using the APM. Some laptops can use this to 2580 turn off the LCD backlight when the screen blanker of the Linux 2581 virtual console blanks the screen. Note that this is only used by 2582 the virtual console screen blanker, and won't turn off the backlight 2583 when using the X Window system. This also doesn't have anything to 2584 do with your VESA-compliant power-saving monitor. Further, this 2585 option doesn't work for all laptops -- it might not turn off your 2586 backlight at all, or it might print a lot of errors to the console, 2587 especially if you are using gpm. 2588 2589config APM_ALLOW_INTS 2590 bool "Allow interrupts during APM BIOS calls" 2591 help 2592 Normally we disable external interrupts while we are making calls to 2593 the APM BIOS as a measure to lessen the effects of a badly behaving 2594 BIOS implementation. The BIOS should reenable interrupts if it 2595 needs to. Unfortunately, some BIOSes do not -- especially those in 2596 many of the newer IBM Thinkpads. If you experience hangs when you 2597 suspend, try setting this to Y. Otherwise, say N. 2598 2599endif # APM 2600 2601source "drivers/cpufreq/Kconfig" 2602 2603source "drivers/cpuidle/Kconfig" 2604 2605source "drivers/idle/Kconfig" 2606 2607endmenu 2608 2609 2610menu "Bus options (PCI etc.)" 2611 2612choice 2613 prompt "PCI access mode" 2614 depends on X86_32 && PCI 2615 default PCI_GOANY 2616 help 2617 On PCI systems, the BIOS can be used to detect the PCI devices and 2618 determine their configuration. However, some old PCI motherboards 2619 have BIOS bugs and may crash if this is done. Also, some embedded 2620 PCI-based systems don't have any BIOS at all. Linux can also try to 2621 detect the PCI hardware directly without using the BIOS. 2622 2623 With this option, you can specify how Linux should detect the 2624 PCI devices. If you choose "BIOS", the BIOS will be used, 2625 if you choose "Direct", the BIOS won't be used, and if you 2626 choose "MMConfig", then PCI Express MMCONFIG will be used. 2627 If you choose "Any", the kernel will try MMCONFIG, then the 2628 direct access method and falls back to the BIOS if that doesn't 2629 work. If unsure, go with the default, which is "Any". 2630 2631config PCI_GOBIOS 2632 bool "BIOS" 2633 2634config PCI_GOMMCONFIG 2635 bool "MMConfig" 2636 2637config PCI_GODIRECT 2638 bool "Direct" 2639 2640config PCI_GOOLPC 2641 bool "OLPC XO-1" 2642 depends on OLPC 2643 2644config PCI_GOANY 2645 bool "Any" 2646 2647endchoice 2648 2649config PCI_BIOS 2650 def_bool y 2651 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2652 2653# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2654config PCI_DIRECT 2655 def_bool y 2656 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2657 2658config PCI_MMCONFIG 2659 bool "Support mmconfig PCI config space access" if X86_64 2660 default y 2661 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2662 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2663 2664config PCI_OLPC 2665 def_bool y 2666 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2667 2668config PCI_XEN 2669 def_bool y 2670 depends on PCI && XEN 2671 2672config MMCONF_FAM10H 2673 def_bool y 2674 depends on X86_64 && PCI_MMCONFIG && ACPI 2675 2676config PCI_CNB20LE_QUIRK 2677 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2678 depends on PCI 2679 help 2680 Read the PCI windows out of the CNB20LE host bridge. This allows 2681 PCI hotplug to work on systems with the CNB20LE chipset which do 2682 not have ACPI. 2683 2684 There's no public spec for this chipset, and this functionality 2685 is known to be incomplete. 2686 2687 You should say N unless you know you need this. 2688 2689config ISA_BUS 2690 bool "ISA bus support on modern systems" if EXPERT 2691 help 2692 Expose ISA bus device drivers and options available for selection and 2693 configuration. Enable this option if your target machine has an ISA 2694 bus. ISA is an older system, displaced by PCI and newer bus 2695 architectures -- if your target machine is modern, it probably does 2696 not have an ISA bus. 2697 2698 If unsure, say N. 2699 2700# x86_64 have no ISA slots, but can have ISA-style DMA. 2701config ISA_DMA_API 2702 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2703 default y 2704 help 2705 Enables ISA-style DMA support for devices requiring such controllers. 2706 If unsure, say Y. 2707 2708if X86_32 2709 2710config ISA 2711 bool "ISA support" 2712 help 2713 Find out whether you have ISA slots on your motherboard. ISA is the 2714 name of a bus system, i.e. the way the CPU talks to the other stuff 2715 inside your box. Other bus systems are PCI, EISA, MicroChannel 2716 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2717 newer boards don't support it. If you have ISA, say Y, otherwise N. 2718 2719config SCx200 2720 tristate "NatSemi SCx200 support" 2721 help 2722 This provides basic support for National Semiconductor's 2723 (now AMD's) Geode processors. The driver probes for the 2724 PCI-IDs of several on-chip devices, so its a good dependency 2725 for other scx200_* drivers. 2726 2727 If compiled as a module, the driver is named scx200. 2728 2729config SCx200HR_TIMER 2730 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2731 depends on SCx200 2732 default y 2733 help 2734 This driver provides a clocksource built upon the on-chip 2735 27MHz high-resolution timer. Its also a workaround for 2736 NSC Geode SC-1100's buggy TSC, which loses time when the 2737 processor goes idle (as is done by the scheduler). The 2738 other workaround is idle=poll boot option. 2739 2740config OLPC 2741 bool "One Laptop Per Child support" 2742 depends on !X86_PAE 2743 select GPIOLIB 2744 select OF 2745 select OF_PROMTREE 2746 select IRQ_DOMAIN 2747 select OLPC_EC 2748 help 2749 Add support for detecting the unique features of the OLPC 2750 XO hardware. 2751 2752config OLPC_XO1_PM 2753 bool "OLPC XO-1 Power Management" 2754 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2755 help 2756 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2757 2758config OLPC_XO1_RTC 2759 bool "OLPC XO-1 Real Time Clock" 2760 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2761 help 2762 Add support for the XO-1 real time clock, which can be used as a 2763 programmable wakeup source. 2764 2765config OLPC_XO1_SCI 2766 bool "OLPC XO-1 SCI extras" 2767 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2768 depends on INPUT=y 2769 select POWER_SUPPLY 2770 help 2771 Add support for SCI-based features of the OLPC XO-1 laptop: 2772 - EC-driven system wakeups 2773 - Power button 2774 - Ebook switch 2775 - Lid switch 2776 - AC adapter status updates 2777 - Battery status updates 2778 2779config OLPC_XO15_SCI 2780 bool "OLPC XO-1.5 SCI extras" 2781 depends on OLPC && ACPI 2782 select POWER_SUPPLY 2783 help 2784 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2785 - EC-driven system wakeups 2786 - AC adapter status updates 2787 - Battery status updates 2788 2789config ALIX 2790 bool "PCEngines ALIX System Support (LED setup)" 2791 select GPIOLIB 2792 help 2793 This option enables system support for the PCEngines ALIX. 2794 At present this just sets up LEDs for GPIO control on 2795 ALIX2/3/6 boards. However, other system specific setup should 2796 get added here. 2797 2798 Note: You must still enable the drivers for GPIO and LED support 2799 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2800 2801 Note: You have to set alix.force=1 for boards with Award BIOS. 2802 2803config NET5501 2804 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2805 select GPIOLIB 2806 help 2807 This option enables system support for the Soekris Engineering net5501. 2808 2809config GEOS 2810 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2811 select GPIOLIB 2812 depends on DMI 2813 help 2814 This option enables system support for the Traverse Technologies GEOS. 2815 2816config TS5500 2817 bool "Technologic Systems TS-5500 platform support" 2818 depends on MELAN 2819 select CHECK_SIGNATURE 2820 select NEW_LEDS 2821 select LEDS_CLASS 2822 help 2823 This option enables system support for the Technologic Systems TS-5500. 2824 2825endif # X86_32 2826 2827config AMD_NB 2828 def_bool y 2829 depends on CPU_SUP_AMD && PCI 2830 2831endmenu 2832 2833 2834menu "Binary Emulations" 2835 2836config IA32_EMULATION 2837 bool "IA32 Emulation" 2838 depends on X86_64 2839 select ARCH_WANT_OLD_COMPAT_IPC 2840 select BINFMT_ELF 2841 select COMPAT_OLD_SIGACTION 2842 help 2843 Include code to run legacy 32-bit programs under a 2844 64-bit kernel. You should likely turn this on, unless you're 2845 100% sure that you don't have any 32-bit programs left. 2846 2847config IA32_AOUT 2848 tristate "IA32 a.out support" 2849 depends on IA32_EMULATION 2850 depends on BROKEN 2851 help 2852 Support old a.out binaries in the 32bit emulation. 2853 2854config X86_X32_ABI 2855 bool "x32 ABI for 64-bit mode" 2856 depends on X86_64 2857 # llvm-objcopy does not convert x86_64 .note.gnu.property or 2858 # compressed debug sections to x86_x32 properly: 2859 # https://github.com/ClangBuiltLinux/linux/issues/514 2860 # https://github.com/ClangBuiltLinux/linux/issues/1141 2861 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 2862 help 2863 Include code to run binaries for the x32 native 32-bit ABI 2864 for 64-bit processors. An x32 process gets access to the 2865 full 64-bit register file and wide data path while leaving 2866 pointers at 32 bits for smaller memory footprint. 2867 2868config COMPAT_32 2869 def_bool y 2870 depends on IA32_EMULATION || X86_32 2871 select HAVE_UID16 2872 select OLD_SIGSUSPEND3 2873 2874config COMPAT 2875 def_bool y 2876 depends on IA32_EMULATION || X86_X32_ABI 2877 2878if COMPAT 2879config COMPAT_FOR_U64_ALIGNMENT 2880 def_bool y 2881 2882config SYSVIPC_COMPAT 2883 def_bool y 2884 depends on SYSVIPC 2885endif 2886 2887endmenu 2888 2889 2890config HAVE_ATOMIC_IOMAP 2891 def_bool y 2892 depends on X86_32 2893 2894source "arch/x86/kvm/Kconfig" 2895 2896source "arch/x86/Kconfig.assembler" 2897