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 || (X86_32 && HIGHMEM) 67 select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG 68 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 69 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 70 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 71 select ARCH_HAS_CACHE_LINE_SIZE 72 select ARCH_HAS_DEBUG_VIRTUAL 73 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 74 select ARCH_HAS_DEVMEM_IS_ALLOWED 75 select ARCH_HAS_EARLY_DEBUG if KGDB 76 select ARCH_HAS_ELF_RANDOMIZE 77 select ARCH_HAS_FAST_MULTIPLIER 78 select ARCH_HAS_FILTER_PGPROT 79 select ARCH_HAS_FORTIFY_SOURCE 80 select ARCH_HAS_GCOV_PROFILE_ALL 81 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 82 select ARCH_HAS_MEM_ENCRYPT 83 select ARCH_HAS_MEMBARRIER_SYNC_CORE 84 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 85 select ARCH_HAS_PMEM_API if X86_64 86 select ARCH_HAS_PTE_DEVMAP if X86_64 87 select ARCH_HAS_PTE_SPECIAL 88 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 89 select ARCH_HAS_COPY_MC if X86_64 90 select ARCH_HAS_SET_MEMORY 91 select ARCH_HAS_SET_DIRECT_MAP 92 select ARCH_HAS_STRICT_KERNEL_RWX 93 select ARCH_HAS_STRICT_MODULE_RWX 94 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 95 select ARCH_HAS_SYSCALL_WRAPPER 96 select ARCH_HAS_UBSAN_SANITIZE_ALL 97 select ARCH_HAS_DEBUG_WX 98 select ARCH_HAS_ZONE_DMA_SET if EXPERT 99 select ARCH_HAVE_NMI_SAFE_CMPXCHG 100 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 101 select ARCH_MIGHT_HAVE_PC_PARPORT 102 select ARCH_MIGHT_HAVE_PC_SERIO 103 select ARCH_STACKWALK 104 select ARCH_SUPPORTS_ACPI 105 select ARCH_SUPPORTS_ATOMIC_RMW 106 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 107 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 108 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 109 select ARCH_SUPPORTS_LTO_CLANG 110 select ARCH_SUPPORTS_LTO_CLANG_THIN 111 select ARCH_USE_BUILTIN_BSWAP 112 select ARCH_USE_MEMTEST 113 select ARCH_USE_QUEUED_RWLOCKS 114 select ARCH_USE_QUEUED_SPINLOCKS 115 select ARCH_USE_SYM_ANNOTATIONS 116 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 117 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 118 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 119 select ARCH_WANTS_NO_INSTR 120 select ARCH_WANT_HUGE_PMD_SHARE 121 select ARCH_WANT_LD_ORPHAN_WARN 122 select ARCH_WANTS_THP_SWAP if X86_64 123 select ARCH_HAS_PARANOID_L1D_FLUSH 124 select BUILDTIME_TABLE_SORT 125 select CLKEVT_I8253 126 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 127 select CLOCKSOURCE_WATCHDOG 128 select DCACHE_WORD_ACCESS 129 select EDAC_ATOMIC_SCRUB 130 select EDAC_SUPPORT 131 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 132 select GENERIC_CLOCKEVENTS_MIN_ADJUST 133 select GENERIC_CMOS_UPDATE 134 select GENERIC_CPU_AUTOPROBE 135 select GENERIC_CPU_VULNERABILITIES 136 select GENERIC_EARLY_IOREMAP 137 select GENERIC_ENTRY 138 select GENERIC_FIND_FIRST_BIT 139 select GENERIC_IOMAP 140 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 141 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 142 select GENERIC_IRQ_MIGRATION if SMP 143 select GENERIC_IRQ_PROBE 144 select GENERIC_IRQ_RESERVATION_MODE 145 select GENERIC_IRQ_SHOW 146 select GENERIC_PENDING_IRQ if SMP 147 select GENERIC_PTDUMP 148 select GENERIC_SMP_IDLE_THREAD 149 select GENERIC_TIME_VSYSCALL 150 select GENERIC_GETTIMEOFDAY 151 select GENERIC_VDSO_TIME_NS 152 select GUP_GET_PTE_LOW_HIGH if X86_PAE 153 select HARDIRQS_SW_RESEND 154 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 155 select HAVE_ACPI_APEI if ACPI 156 select HAVE_ACPI_APEI_NMI if ACPI 157 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 158 select HAVE_ARCH_AUDITSYSCALL 159 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 160 select HAVE_ARCH_JUMP_LABEL 161 select HAVE_ARCH_JUMP_LABEL_RELATIVE 162 select HAVE_ARCH_KASAN if X86_64 163 select HAVE_ARCH_KASAN_VMALLOC if X86_64 164 select HAVE_ARCH_KFENCE 165 select HAVE_ARCH_KGDB 166 select HAVE_ARCH_MMAP_RND_BITS if MMU 167 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 168 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 169 select HAVE_ARCH_PREL32_RELOCATIONS 170 select HAVE_ARCH_SECCOMP_FILTER 171 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 172 select HAVE_ARCH_STACKLEAK 173 select HAVE_ARCH_TRACEHOOK 174 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 175 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 176 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 177 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 178 select HAVE_ARCH_VMAP_STACK if X86_64 179 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 180 select HAVE_ARCH_WITHIN_STACK_FRAMES 181 select HAVE_ASM_MODVERSIONS 182 select HAVE_CMPXCHG_DOUBLE 183 select HAVE_CMPXCHG_LOCAL 184 select HAVE_CONTEXT_TRACKING if X86_64 185 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING 186 select HAVE_C_RECORDMCOUNT 187 select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION 188 select HAVE_DEBUG_KMEMLEAK 189 select HAVE_DMA_CONTIGUOUS 190 select HAVE_DYNAMIC_FTRACE 191 select HAVE_DYNAMIC_FTRACE_WITH_REGS 192 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 193 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 194 select HAVE_EBPF_JIT 195 select HAVE_EFFICIENT_UNALIGNED_ACCESS 196 select HAVE_EISA 197 select HAVE_EXIT_THREAD 198 select HAVE_FAST_GUP 199 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 200 select HAVE_FTRACE_MCOUNT_RECORD 201 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 202 select HAVE_FUNCTION_TRACER 203 select HAVE_GCC_PLUGINS 204 select HAVE_HW_BREAKPOINT 205 select HAVE_IOREMAP_PROT 206 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 207 select HAVE_IRQ_TIME_ACCOUNTING 208 select HAVE_KERNEL_BZIP2 209 select HAVE_KERNEL_GZIP 210 select HAVE_KERNEL_LZ4 211 select HAVE_KERNEL_LZMA 212 select HAVE_KERNEL_LZO 213 select HAVE_KERNEL_XZ 214 select HAVE_KERNEL_ZSTD 215 select HAVE_KPROBES 216 select HAVE_KPROBES_ON_FTRACE 217 select HAVE_FUNCTION_ERROR_INJECTION 218 select HAVE_KRETPROBES 219 select HAVE_KVM 220 select HAVE_LIVEPATCH if X86_64 221 select HAVE_MIXED_BREAKPOINTS_REGS 222 select HAVE_MOD_ARCH_SPECIFIC 223 select HAVE_MOVE_PMD 224 select HAVE_MOVE_PUD 225 select HAVE_NMI 226 select HAVE_OPTPROBES 227 select HAVE_PCSPKR_PLATFORM 228 select HAVE_PERF_EVENTS 229 select HAVE_PERF_EVENTS_NMI 230 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 231 select HAVE_PCI 232 select HAVE_PERF_REGS 233 select HAVE_PERF_USER_STACK_DUMP 234 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 235 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 236 select HAVE_REGS_AND_STACK_ACCESS_API 237 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 238 select HAVE_FUNCTION_ARG_ACCESS_API 239 select HAVE_SOFTIRQ_ON_OWN_STACK 240 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 241 select HAVE_STACK_VALIDATION if X86_64 242 select HAVE_STATIC_CALL 243 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 244 select HAVE_PREEMPT_DYNAMIC 245 select HAVE_RSEQ 246 select HAVE_SYSCALL_TRACEPOINTS 247 select HAVE_UNSTABLE_SCHED_CLOCK 248 select HAVE_USER_RETURN_NOTIFIER 249 select HAVE_GENERIC_VDSO 250 select HOTPLUG_SMT if SMP 251 select IRQ_FORCED_THREADING 252 select NEED_SG_DMA_LENGTH 253 select PCI_DOMAINS if PCI 254 select PCI_LOCKLESS_CONFIG if PCI 255 select PERF_EVENTS 256 select RTC_LIB 257 select RTC_MC146818_LIB 258 select SPARSE_IRQ 259 select SRCU 260 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 261 select SYSCTL_EXCEPTION_TRACE 262 select THREAD_INFO_IN_TASK 263 select TRACE_IRQFLAGS_SUPPORT 264 select USER_STACKTRACE_SUPPORT 265 select VIRT_TO_BUS 266 select HAVE_ARCH_KCSAN if X86_64 267 select X86_FEATURE_NAMES if PROC_FS 268 select PROC_PID_ARCH_STATUS if PROC_FS 269 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 270 271config INSTRUCTION_DECODER 272 def_bool y 273 depends on KPROBES || PERF_EVENTS || UPROBES 274 275config OUTPUT_FORMAT 276 string 277 default "elf32-i386" if X86_32 278 default "elf64-x86-64" if X86_64 279 280config LOCKDEP_SUPPORT 281 def_bool y 282 283config STACKTRACE_SUPPORT 284 def_bool y 285 286config MMU 287 def_bool y 288 289config ARCH_MMAP_RND_BITS_MIN 290 default 28 if 64BIT 291 default 8 292 293config ARCH_MMAP_RND_BITS_MAX 294 default 32 if 64BIT 295 default 16 296 297config ARCH_MMAP_RND_COMPAT_BITS_MIN 298 default 8 299 300config ARCH_MMAP_RND_COMPAT_BITS_MAX 301 default 16 302 303config SBUS 304 bool 305 306config GENERIC_ISA_DMA 307 def_bool y 308 depends on ISA_DMA_API 309 310config GENERIC_BUG 311 def_bool y 312 depends on BUG 313 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 314 315config GENERIC_BUG_RELATIVE_POINTERS 316 bool 317 318config ARCH_MAY_HAVE_PC_FDC 319 def_bool y 320 depends on ISA_DMA_API 321 322config GENERIC_CALIBRATE_DELAY 323 def_bool y 324 325config ARCH_HAS_CPU_RELAX 326 def_bool y 327 328config ARCH_HAS_FILTER_PGPROT 329 def_bool y 330 331config HAVE_SETUP_PER_CPU_AREA 332 def_bool y 333 334config NEED_PER_CPU_EMBED_FIRST_CHUNK 335 def_bool y 336 337config NEED_PER_CPU_PAGE_FIRST_CHUNK 338 def_bool y 339 340config ARCH_HIBERNATION_POSSIBLE 341 def_bool y 342 343config ARCH_NR_GPIO 344 int 345 default 1024 if X86_64 346 default 512 347 348config ARCH_SUSPEND_POSSIBLE 349 def_bool y 350 351config ARCH_WANT_GENERAL_HUGETLB 352 def_bool y 353 354config AUDIT_ARCH 355 def_bool y if X86_64 356 357config KASAN_SHADOW_OFFSET 358 hex 359 depends on KASAN 360 default 0xdffffc0000000000 361 362config HAVE_INTEL_TXT 363 def_bool y 364 depends on INTEL_IOMMU && ACPI 365 366config X86_32_SMP 367 def_bool y 368 depends on X86_32 && SMP 369 370config X86_64_SMP 371 def_bool y 372 depends on X86_64 && SMP 373 374config ARCH_SUPPORTS_UPROBES 375 def_bool y 376 377config FIX_EARLYCON_MEM 378 def_bool y 379 380config DYNAMIC_PHYSICAL_MASK 381 bool 382 383config PGTABLE_LEVELS 384 int 385 default 5 if X86_5LEVEL 386 default 4 if X86_64 387 default 3 if X86_PAE 388 default 2 389 390config CC_HAS_SANE_STACKPROTECTOR 391 bool 392 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 393 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 394 help 395 We have to make sure stack protector is unconditionally disabled if 396 the compiler produces broken code or if it does not let us control 397 the segment on 32-bit kernels. 398 399menu "Processor type and features" 400 401config SMP 402 bool "Symmetric multi-processing support" 403 help 404 This enables support for systems with more than one CPU. If you have 405 a system with only one CPU, say N. If you have a system with more 406 than one CPU, say Y. 407 408 If you say N here, the kernel will run on uni- and multiprocessor 409 machines, but will use only one CPU of a multiprocessor machine. If 410 you say Y here, the kernel will run on many, but not all, 411 uniprocessor machines. On a uniprocessor machine, the kernel 412 will run faster if you say N here. 413 414 Note that if you say Y here and choose architecture "586" or 415 "Pentium" under "Processor family", the kernel will not work on 486 416 architectures. Similarly, multiprocessor kernels for the "PPro" 417 architecture may not work on all Pentium based boards. 418 419 People using multiprocessor machines who say Y here should also say 420 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 421 Management" code will be disabled if you say Y here. 422 423 See also <file:Documentation/x86/i386/IO-APIC.rst>, 424 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 425 <http://www.tldp.org/docs.html#howto>. 426 427 If you don't know what to do here, say N. 428 429config X86_FEATURE_NAMES 430 bool "Processor feature human-readable names" if EMBEDDED 431 default y 432 help 433 This option compiles in a table of x86 feature bits and corresponding 434 names. This is required to support /proc/cpuinfo and a few kernel 435 messages. You can disable this to save space, at the expense of 436 making those few kernel messages show numeric feature bits instead. 437 438 If in doubt, say Y. 439 440config X86_X2APIC 441 bool "Support x2apic" 442 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 443 help 444 This enables x2apic support on CPUs that have this feature. 445 446 This allows 32-bit apic IDs (so it can support very large systems), 447 and accesses the local apic via MSRs not via mmio. 448 449 If you don't know what to do here, say N. 450 451config X86_MPPARSE 452 bool "Enable MPS table" if ACPI 453 default y 454 depends on X86_LOCAL_APIC 455 help 456 For old smp systems that do not have proper acpi support. Newer systems 457 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 458 459config GOLDFISH 460 def_bool y 461 depends on X86_GOLDFISH 462 463config RETPOLINE 464 bool "Avoid speculative indirect branches in kernel" 465 default y 466 help 467 Compile kernel with the retpoline compiler options to guard against 468 kernel-to-user data leaks by avoiding speculative indirect 469 branches. Requires a compiler with -mindirect-branch=thunk-extern 470 support for full protection. The kernel may run slower. 471 472config X86_CPU_RESCTRL 473 bool "x86 CPU resource control support" 474 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 475 select KERNFS 476 select PROC_CPU_RESCTRL if PROC_FS 477 help 478 Enable x86 CPU resource control support. 479 480 Provide support for the allocation and monitoring of system resources 481 usage by the CPU. 482 483 Intel calls this Intel Resource Director Technology 484 (Intel(R) RDT). More information about RDT can be found in the 485 Intel x86 Architecture Software Developer Manual. 486 487 AMD calls this AMD Platform Quality of Service (AMD QoS). 488 More information about AMD QoS can be found in the AMD64 Technology 489 Platform Quality of Service Extensions manual. 490 491 Say N if unsure. 492 493if X86_32 494config X86_BIGSMP 495 bool "Support for big SMP systems with more than 8 CPUs" 496 depends on SMP 497 help 498 This option is needed for the systems that have more than 8 CPUs. 499 500config X86_EXTENDED_PLATFORM 501 bool "Support for extended (non-PC) x86 platforms" 502 default y 503 help 504 If you disable this option then the kernel will only support 505 standard PC platforms. (which covers the vast majority of 506 systems out there.) 507 508 If you enable this option then you'll be able to select support 509 for the following (non-PC) 32 bit x86 platforms: 510 Goldfish (Android emulator) 511 AMD Elan 512 RDC R-321x SoC 513 SGI 320/540 (Visual Workstation) 514 STA2X11-based (e.g. Northville) 515 Moorestown MID devices 516 517 If you have one of these systems, or if you want to build a 518 generic distribution kernel, say Y here - otherwise say N. 519endif 520 521if X86_64 522config X86_EXTENDED_PLATFORM 523 bool "Support for extended (non-PC) x86 platforms" 524 default y 525 help 526 If you disable this option then the kernel will only support 527 standard PC platforms. (which covers the vast majority of 528 systems out there.) 529 530 If you enable this option then you'll be able to select support 531 for the following (non-PC) 64 bit x86 platforms: 532 Numascale NumaChip 533 ScaleMP vSMP 534 SGI Ultraviolet 535 536 If you have one of these systems, or if you want to build a 537 generic distribution kernel, say Y here - otherwise say N. 538endif 539# This is an alphabetically sorted list of 64 bit extended platforms 540# Please maintain the alphabetic order if and when there are additions 541config X86_NUMACHIP 542 bool "Numascale NumaChip" 543 depends on X86_64 544 depends on X86_EXTENDED_PLATFORM 545 depends on NUMA 546 depends on SMP 547 depends on X86_X2APIC 548 depends on PCI_MMCONFIG 549 help 550 Adds support for Numascale NumaChip large-SMP systems. Needed to 551 enable more than ~168 cores. 552 If you don't have one of these, you should say N here. 553 554config X86_VSMP 555 bool "ScaleMP vSMP" 556 select HYPERVISOR_GUEST 557 select PARAVIRT 558 depends on X86_64 && PCI 559 depends on X86_EXTENDED_PLATFORM 560 depends on SMP 561 help 562 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 563 supposed to run on these EM64T-based machines. Only choose this option 564 if you have one of these machines. 565 566config X86_UV 567 bool "SGI Ultraviolet" 568 depends on X86_64 569 depends on X86_EXTENDED_PLATFORM 570 depends on NUMA 571 depends on EFI 572 depends on KEXEC_CORE 573 depends on X86_X2APIC 574 depends on PCI 575 help 576 This option is needed in order to support SGI Ultraviolet systems. 577 If you don't have one of these, you should say N here. 578 579# Following is an alphabetically sorted list of 32 bit extended platforms 580# Please maintain the alphabetic order if and when there are additions 581 582config X86_GOLDFISH 583 bool "Goldfish (Virtual Platform)" 584 depends on X86_EXTENDED_PLATFORM 585 help 586 Enable support for the Goldfish virtual platform used primarily 587 for Android development. Unless you are building for the Android 588 Goldfish emulator say N here. 589 590config X86_INTEL_CE 591 bool "CE4100 TV platform" 592 depends on PCI 593 depends on PCI_GODIRECT 594 depends on X86_IO_APIC 595 depends on X86_32 596 depends on X86_EXTENDED_PLATFORM 597 select X86_REBOOTFIXUPS 598 select OF 599 select OF_EARLY_FLATTREE 600 help 601 Select for the Intel CE media processor (CE4100) SOC. 602 This option compiles in support for the CE4100 SOC for settop 603 boxes and media devices. 604 605config X86_INTEL_MID 606 bool "Intel MID platform support" 607 depends on X86_EXTENDED_PLATFORM 608 depends on X86_PLATFORM_DEVICES 609 depends on PCI 610 depends on X86_64 || (PCI_GOANY && X86_32) 611 depends on X86_IO_APIC 612 select I2C 613 select DW_APB_TIMER 614 select APB_TIMER 615 select INTEL_SCU_PCI 616 select MFD_INTEL_MSIC 617 help 618 Select to build a kernel capable of supporting Intel MID (Mobile 619 Internet Device) platform systems which do not have the PCI legacy 620 interfaces. If you are building for a PC class system say N here. 621 622 Intel MID platforms are based on an Intel processor and chipset which 623 consume less power than most of the x86 derivatives. 624 625config X86_INTEL_QUARK 626 bool "Intel Quark platform support" 627 depends on X86_32 628 depends on X86_EXTENDED_PLATFORM 629 depends on X86_PLATFORM_DEVICES 630 depends on X86_TSC 631 depends on PCI 632 depends on PCI_GOANY 633 depends on X86_IO_APIC 634 select IOSF_MBI 635 select INTEL_IMR 636 select COMMON_CLK 637 help 638 Select to include support for Quark X1000 SoC. 639 Say Y here if you have a Quark based system such as the Arduino 640 compatible Intel Galileo. 641 642config X86_INTEL_LPSS 643 bool "Intel Low Power Subsystem Support" 644 depends on X86 && ACPI && PCI 645 select COMMON_CLK 646 select PINCTRL 647 select IOSF_MBI 648 help 649 Select to build support for Intel Low Power Subsystem such as 650 found on Intel Lynxpoint PCH. Selecting this option enables 651 things like clock tree (common clock framework) and pincontrol 652 which are needed by the LPSS peripheral drivers. 653 654config X86_AMD_PLATFORM_DEVICE 655 bool "AMD ACPI2Platform devices support" 656 depends on ACPI 657 select COMMON_CLK 658 select PINCTRL 659 help 660 Select to interpret AMD specific ACPI device to platform device 661 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 662 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 663 implemented under PINCTRL subsystem. 664 665config IOSF_MBI 666 tristate "Intel SoC IOSF Sideband support for SoC platforms" 667 depends on PCI 668 help 669 This option enables sideband register access support for Intel SoC 670 platforms. On these platforms the IOSF sideband is used in lieu of 671 MSR's for some register accesses, mostly but not limited to thermal 672 and power. Drivers may query the availability of this device to 673 determine if they need the sideband in order to work on these 674 platforms. The sideband is available on the following SoC products. 675 This list is not meant to be exclusive. 676 - BayTrail 677 - Braswell 678 - Quark 679 680 You should say Y if you are running a kernel on one of these SoC's. 681 682config IOSF_MBI_DEBUG 683 bool "Enable IOSF sideband access through debugfs" 684 depends on IOSF_MBI && DEBUG_FS 685 help 686 Select this option to expose the IOSF sideband access registers (MCR, 687 MDR, MCRX) through debugfs to write and read register information from 688 different units on the SoC. This is most useful for obtaining device 689 state information for debug and analysis. As this is a general access 690 mechanism, users of this option would have specific knowledge of the 691 device they want to access. 692 693 If you don't require the option or are in doubt, say N. 694 695config X86_RDC321X 696 bool "RDC R-321x SoC" 697 depends on X86_32 698 depends on X86_EXTENDED_PLATFORM 699 select M486 700 select X86_REBOOTFIXUPS 701 help 702 This option is needed for RDC R-321x system-on-chip, also known 703 as R-8610-(G). 704 If you don't have one of these chips, you should say N here. 705 706config X86_32_NON_STANDARD 707 bool "Support non-standard 32-bit SMP architectures" 708 depends on X86_32 && SMP 709 depends on X86_EXTENDED_PLATFORM 710 help 711 This option compiles in the bigsmp and STA2X11 default 712 subarchitectures. It is intended for a generic binary 713 kernel. If you select them all, kernel will probe it one by 714 one and will fallback to default. 715 716# Alphabetically sorted list of Non standard 32 bit platforms 717 718config X86_SUPPORTS_MEMORY_FAILURE 719 def_bool y 720 # MCE code calls memory_failure(): 721 depends on X86_MCE 722 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 723 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 724 depends on X86_64 || !SPARSEMEM 725 select ARCH_SUPPORTS_MEMORY_FAILURE 726 727config STA2X11 728 bool "STA2X11 Companion Chip Support" 729 depends on X86_32_NON_STANDARD && PCI 730 select SWIOTLB 731 select MFD_STA2X11 732 select GPIOLIB 733 help 734 This adds support for boards based on the STA2X11 IO-Hub, 735 a.k.a. "ConneXt". The chip is used in place of the standard 736 PC chipset, so all "standard" peripherals are missing. If this 737 option is selected the kernel will still be able to boot on 738 standard PC machines. 739 740config X86_32_IRIS 741 tristate "Eurobraille/Iris poweroff module" 742 depends on X86_32 743 help 744 The Iris machines from EuroBraille do not have APM or ACPI support 745 to shut themselves down properly. A special I/O sequence is 746 needed to do so, which is what this module does at 747 kernel shutdown. 748 749 This is only for Iris machines from EuroBraille. 750 751 If unused, say N. 752 753config SCHED_OMIT_FRAME_POINTER 754 def_bool y 755 prompt "Single-depth WCHAN output" 756 depends on X86 757 help 758 Calculate simpler /proc/<PID>/wchan values. If this option 759 is disabled then wchan values will recurse back to the 760 caller function. This provides more accurate wchan values, 761 at the expense of slightly more scheduling overhead. 762 763 If in doubt, say "Y". 764 765menuconfig HYPERVISOR_GUEST 766 bool "Linux guest support" 767 help 768 Say Y here to enable options for running Linux under various hyper- 769 visors. This option enables basic hypervisor detection and platform 770 setup. 771 772 If you say N, all options in this submenu will be skipped and 773 disabled, and Linux guest support won't be built in. 774 775if HYPERVISOR_GUEST 776 777config PARAVIRT 778 bool "Enable paravirtualization code" 779 depends on HAVE_STATIC_CALL 780 help 781 This changes the kernel so it can modify itself when it is run 782 under a hypervisor, potentially improving performance significantly 783 over full virtualization. However, when run without a hypervisor 784 the kernel is theoretically slower and slightly larger. 785 786config PARAVIRT_XXL 787 bool 788 789config PARAVIRT_DEBUG 790 bool "paravirt-ops debugging" 791 depends on PARAVIRT && DEBUG_KERNEL 792 help 793 Enable to debug paravirt_ops internals. Specifically, BUG if 794 a paravirt_op is missing when it is called. 795 796config PARAVIRT_SPINLOCKS 797 bool "Paravirtualization layer for spinlocks" 798 depends on PARAVIRT && SMP 799 help 800 Paravirtualized spinlocks allow a pvops backend to replace the 801 spinlock implementation with something virtualization-friendly 802 (for example, block the virtual CPU rather than spinning). 803 804 It has a minimal impact on native kernels and gives a nice performance 805 benefit on paravirtualized KVM / Xen kernels. 806 807 If you are unsure how to answer this question, answer Y. 808 809config X86_HV_CALLBACK_VECTOR 810 def_bool n 811 812source "arch/x86/xen/Kconfig" 813 814config KVM_GUEST 815 bool "KVM Guest support (including kvmclock)" 816 depends on PARAVIRT 817 select PARAVIRT_CLOCK 818 select ARCH_CPUIDLE_HALTPOLL 819 select X86_HV_CALLBACK_VECTOR 820 default y 821 help 822 This option enables various optimizations for running under the KVM 823 hypervisor. It includes a paravirtualized clock, so that instead 824 of relying on a PIT (or probably other) emulation by the 825 underlying device model, the host provides the guest with 826 timing infrastructure such as time of day, and system time 827 828config ARCH_CPUIDLE_HALTPOLL 829 def_bool n 830 prompt "Disable host haltpoll when loading haltpoll driver" 831 help 832 If virtualized under KVM, disable host haltpoll. 833 834config PVH 835 bool "Support for running PVH guests" 836 help 837 This option enables the PVH entry point for guest virtual machines 838 as specified in the x86/HVM direct boot ABI. 839 840config PARAVIRT_TIME_ACCOUNTING 841 bool "Paravirtual steal time accounting" 842 depends on PARAVIRT 843 help 844 Select this option to enable fine granularity task steal time 845 accounting. Time spent executing other tasks in parallel with 846 the current vCPU is discounted from the vCPU power. To account for 847 that, there can be a small performance impact. 848 849 If in doubt, say N here. 850 851config PARAVIRT_CLOCK 852 bool 853 854config JAILHOUSE_GUEST 855 bool "Jailhouse non-root cell support" 856 depends on X86_64 && PCI 857 select X86_PM_TIMER 858 help 859 This option allows to run Linux as guest in a Jailhouse non-root 860 cell. You can leave this option disabled if you only want to start 861 Jailhouse and run Linux afterwards in the root cell. 862 863config ACRN_GUEST 864 bool "ACRN Guest support" 865 depends on X86_64 866 select X86_HV_CALLBACK_VECTOR 867 help 868 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 869 a flexible, lightweight reference open-source hypervisor, built with 870 real-time and safety-criticality in mind. It is built for embedded 871 IOT with small footprint and real-time features. More details can be 872 found in https://projectacrn.org/. 873 874endif #HYPERVISOR_GUEST 875 876source "arch/x86/Kconfig.cpu" 877 878config HPET_TIMER 879 def_bool X86_64 880 prompt "HPET Timer Support" if X86_32 881 help 882 Use the IA-PC HPET (High Precision Event Timer) to manage 883 time in preference to the PIT and RTC, if a HPET is 884 present. 885 HPET is the next generation timer replacing legacy 8254s. 886 The HPET provides a stable time base on SMP 887 systems, unlike the TSC, but it is more expensive to access, 888 as it is off-chip. The interface used is documented 889 in the HPET spec, revision 1. 890 891 You can safely choose Y here. However, HPET will only be 892 activated if the platform and the BIOS support this feature. 893 Otherwise the 8254 will be used for timing services. 894 895 Choose N to continue using the legacy 8254 timer. 896 897config HPET_EMULATE_RTC 898 def_bool y 899 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 900 901# Mark as expert because too many people got it wrong. 902# The code disables itself when not needed. 903config DMI 904 default y 905 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 906 bool "Enable DMI scanning" if EXPERT 907 help 908 Enabled scanning of DMI to identify machine quirks. Say Y 909 here unless you have verified that your setup is not 910 affected by entries in the DMI blacklist. Required by PNP 911 BIOS code. 912 913config GART_IOMMU 914 bool "Old AMD GART IOMMU support" 915 select DMA_OPS 916 select IOMMU_HELPER 917 select SWIOTLB 918 depends on X86_64 && PCI && AMD_NB 919 help 920 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 921 GART based hardware IOMMUs. 922 923 The GART supports full DMA access for devices with 32-bit access 924 limitations, on systems with more than 3 GB. This is usually needed 925 for USB, sound, many IDE/SATA chipsets and some other devices. 926 927 Newer systems typically have a modern AMD IOMMU, supported via 928 the CONFIG_AMD_IOMMU=y config option. 929 930 In normal configurations this driver is only active when needed: 931 there's more than 3 GB of memory and the system contains a 932 32-bit limited device. 933 934 If unsure, say Y. 935 936config MAXSMP 937 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 938 depends on X86_64 && SMP && DEBUG_KERNEL 939 select CPUMASK_OFFSTACK 940 help 941 Enable maximum number of CPUS and NUMA Nodes for this architecture. 942 If unsure, say N. 943 944# 945# The maximum number of CPUs supported: 946# 947# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 948# and which can be configured interactively in the 949# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 950# 951# The ranges are different on 32-bit and 64-bit kernels, depending on 952# hardware capabilities and scalability features of the kernel. 953# 954# ( If MAXSMP is enabled we just use the highest possible value and disable 955# interactive configuration. ) 956# 957 958config NR_CPUS_RANGE_BEGIN 959 int 960 default NR_CPUS_RANGE_END if MAXSMP 961 default 1 if !SMP 962 default 2 963 964config NR_CPUS_RANGE_END 965 int 966 depends on X86_32 967 default 64 if SMP && X86_BIGSMP 968 default 8 if SMP && !X86_BIGSMP 969 default 1 if !SMP 970 971config NR_CPUS_RANGE_END 972 int 973 depends on X86_64 974 default 8192 if SMP && CPUMASK_OFFSTACK 975 default 512 if SMP && !CPUMASK_OFFSTACK 976 default 1 if !SMP 977 978config NR_CPUS_DEFAULT 979 int 980 depends on X86_32 981 default 32 if X86_BIGSMP 982 default 8 if SMP 983 default 1 if !SMP 984 985config NR_CPUS_DEFAULT 986 int 987 depends on X86_64 988 default 8192 if MAXSMP 989 default 64 if SMP 990 default 1 if !SMP 991 992config NR_CPUS 993 int "Maximum number of CPUs" if SMP && !MAXSMP 994 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 995 default NR_CPUS_DEFAULT 996 help 997 This allows you to specify the maximum number of CPUs which this 998 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 999 supported value is 8192, otherwise the maximum value is 512. The 1000 minimum value which makes sense is 2. 1001 1002 This is purely to save memory: each supported CPU adds about 8KB 1003 to the kernel image. 1004 1005config SCHED_SMT 1006 def_bool y if SMP 1007 1008config SCHED_MC 1009 def_bool y 1010 prompt "Multi-core scheduler support" 1011 depends on SMP 1012 help 1013 Multi-core scheduler support improves the CPU scheduler's decision 1014 making when dealing with multi-core CPU chips at a cost of slightly 1015 increased overhead in some places. If unsure say N here. 1016 1017config SCHED_MC_PRIO 1018 bool "CPU core priorities scheduler support" 1019 depends on SCHED_MC && CPU_SUP_INTEL 1020 select X86_INTEL_PSTATE 1021 select CPU_FREQ 1022 default y 1023 help 1024 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1025 core ordering determined at manufacturing time, which allows 1026 certain cores to reach higher turbo frequencies (when running 1027 single threaded workloads) than others. 1028 1029 Enabling this kernel feature teaches the scheduler about 1030 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1031 scheduler's CPU selection logic accordingly, so that higher 1032 overall system performance can be achieved. 1033 1034 This feature will have no effect on CPUs without this feature. 1035 1036 If unsure say Y here. 1037 1038config UP_LATE_INIT 1039 def_bool y 1040 depends on !SMP && X86_LOCAL_APIC 1041 1042config X86_UP_APIC 1043 bool "Local APIC support on uniprocessors" if !PCI_MSI 1044 default PCI_MSI 1045 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1046 help 1047 A local APIC (Advanced Programmable Interrupt Controller) is an 1048 integrated interrupt controller in the CPU. If you have a single-CPU 1049 system which has a processor with a local APIC, you can say Y here to 1050 enable and use it. If you say Y here even though your machine doesn't 1051 have a local APIC, then the kernel will still run with no slowdown at 1052 all. The local APIC supports CPU-generated self-interrupts (timer, 1053 performance counters), and the NMI watchdog which detects hard 1054 lockups. 1055 1056config X86_UP_IOAPIC 1057 bool "IO-APIC support on uniprocessors" 1058 depends on X86_UP_APIC 1059 help 1060 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1061 SMP-capable replacement for PC-style interrupt controllers. Most 1062 SMP systems and many recent uniprocessor systems have one. 1063 1064 If you have a single-CPU system with an IO-APIC, you can say Y here 1065 to use it. If you say Y here even though your machine doesn't have 1066 an IO-APIC, then the kernel will still run with no slowdown at all. 1067 1068config X86_LOCAL_APIC 1069 def_bool y 1070 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1071 select IRQ_DOMAIN_HIERARCHY 1072 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1073 1074config X86_IO_APIC 1075 def_bool y 1076 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1077 1078config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1079 bool "Reroute for broken boot IRQs" 1080 depends on X86_IO_APIC 1081 help 1082 This option enables a workaround that fixes a source of 1083 spurious interrupts. This is recommended when threaded 1084 interrupt handling is used on systems where the generation of 1085 superfluous "boot interrupts" cannot be disabled. 1086 1087 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1088 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1089 kernel does during interrupt handling). On chipsets where this 1090 boot IRQ generation cannot be disabled, this workaround keeps 1091 the original IRQ line masked so that only the equivalent "boot 1092 IRQ" is delivered to the CPUs. The workaround also tells the 1093 kernel to set up the IRQ handler on the boot IRQ line. In this 1094 way only one interrupt is delivered to the kernel. Otherwise 1095 the spurious second interrupt may cause the kernel to bring 1096 down (vital) interrupt lines. 1097 1098 Only affects "broken" chipsets. Interrupt sharing may be 1099 increased on these systems. 1100 1101config X86_MCE 1102 bool "Machine Check / overheating reporting" 1103 select GENERIC_ALLOCATOR 1104 default y 1105 help 1106 Machine Check support allows the processor to notify the 1107 kernel if it detects a problem (e.g. overheating, data corruption). 1108 The action the kernel takes depends on the severity of the problem, 1109 ranging from warning messages to halting the machine. 1110 1111config X86_MCELOG_LEGACY 1112 bool "Support for deprecated /dev/mcelog character device" 1113 depends on X86_MCE 1114 help 1115 Enable support for /dev/mcelog which is needed by the old mcelog 1116 userspace logging daemon. Consider switching to the new generation 1117 rasdaemon solution. 1118 1119config X86_MCE_INTEL 1120 def_bool y 1121 prompt "Intel MCE features" 1122 depends on X86_MCE && X86_LOCAL_APIC 1123 help 1124 Additional support for intel specific MCE features such as 1125 the thermal monitor. 1126 1127config X86_MCE_AMD 1128 def_bool y 1129 prompt "AMD MCE features" 1130 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1131 help 1132 Additional support for AMD specific MCE features such as 1133 the DRAM Error Threshold. 1134 1135config X86_ANCIENT_MCE 1136 bool "Support for old Pentium 5 / WinChip machine checks" 1137 depends on X86_32 && X86_MCE 1138 help 1139 Include support for machine check handling on old Pentium 5 or WinChip 1140 systems. These typically need to be enabled explicitly on the command 1141 line. 1142 1143config X86_MCE_THRESHOLD 1144 depends on X86_MCE_AMD || X86_MCE_INTEL 1145 def_bool y 1146 1147config X86_MCE_INJECT 1148 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1149 tristate "Machine check injector support" 1150 help 1151 Provide support for injecting machine checks for testing purposes. 1152 If you don't know what a machine check is and you don't do kernel 1153 QA it is safe to say n. 1154 1155source "arch/x86/events/Kconfig" 1156 1157config X86_LEGACY_VM86 1158 bool "Legacy VM86 support" 1159 depends on X86_32 1160 help 1161 This option allows user programs to put the CPU into V8086 1162 mode, which is an 80286-era approximation of 16-bit real mode. 1163 1164 Some very old versions of X and/or vbetool require this option 1165 for user mode setting. Similarly, DOSEMU will use it if 1166 available to accelerate real mode DOS programs. However, any 1167 recent version of DOSEMU, X, or vbetool should be fully 1168 functional even without kernel VM86 support, as they will all 1169 fall back to software emulation. Nevertheless, if you are using 1170 a 16-bit DOS program where 16-bit performance matters, vm86 1171 mode might be faster than emulation and you might want to 1172 enable this option. 1173 1174 Note that any app that works on a 64-bit kernel is unlikely to 1175 need this option, as 64-bit kernels don't, and can't, support 1176 V8086 mode. This option is also unrelated to 16-bit protected 1177 mode and is not needed to run most 16-bit programs under Wine. 1178 1179 Enabling this option increases the complexity of the kernel 1180 and slows down exception handling a tiny bit. 1181 1182 If unsure, say N here. 1183 1184config VM86 1185 bool 1186 default X86_LEGACY_VM86 1187 1188config X86_16BIT 1189 bool "Enable support for 16-bit segments" if EXPERT 1190 default y 1191 depends on MODIFY_LDT_SYSCALL 1192 help 1193 This option is required by programs like Wine to run 16-bit 1194 protected mode legacy code on x86 processors. Disabling 1195 this option saves about 300 bytes on i386, or around 6K text 1196 plus 16K runtime memory on x86-64, 1197 1198config X86_ESPFIX32 1199 def_bool y 1200 depends on X86_16BIT && X86_32 1201 1202config X86_ESPFIX64 1203 def_bool y 1204 depends on X86_16BIT && X86_64 1205 1206config X86_VSYSCALL_EMULATION 1207 bool "Enable vsyscall emulation" if EXPERT 1208 default y 1209 depends on X86_64 1210 help 1211 This enables emulation of the legacy vsyscall page. Disabling 1212 it is roughly equivalent to booting with vsyscall=none, except 1213 that it will also disable the helpful warning if a program 1214 tries to use a vsyscall. With this option set to N, offending 1215 programs will just segfault, citing addresses of the form 1216 0xffffffffff600?00. 1217 1218 This option is required by many programs built before 2013, and 1219 care should be used even with newer programs if set to N. 1220 1221 Disabling this option saves about 7K of kernel size and 1222 possibly 4K of additional runtime pagetable memory. 1223 1224config X86_IOPL_IOPERM 1225 bool "IOPERM and IOPL Emulation" 1226 default y 1227 help 1228 This enables the ioperm() and iopl() syscalls which are necessary 1229 for legacy applications. 1230 1231 Legacy IOPL support is an overbroad mechanism which allows user 1232 space aside of accessing all 65536 I/O ports also to disable 1233 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1234 capabilities and permission from potentially active security 1235 modules. 1236 1237 The emulation restricts the functionality of the syscall to 1238 only allowing the full range I/O port access, but prevents the 1239 ability to disable interrupts from user space which would be 1240 granted if the hardware IOPL mechanism would be used. 1241 1242config TOSHIBA 1243 tristate "Toshiba Laptop support" 1244 depends on X86_32 1245 help 1246 This adds a driver to safely access the System Management Mode of 1247 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1248 not work on models with a Phoenix BIOS. The System Management Mode 1249 is used to set the BIOS and power saving options on Toshiba portables. 1250 1251 For information on utilities to make use of this driver see the 1252 Toshiba Linux utilities web site at: 1253 <http://www.buzzard.org.uk/toshiba/>. 1254 1255 Say Y if you intend to run this kernel on a Toshiba portable. 1256 Say N otherwise. 1257 1258config I8K 1259 tristate "Dell i8k legacy laptop support" 1260 select HWMON 1261 select SENSORS_DELL_SMM 1262 help 1263 This option enables legacy /proc/i8k userspace interface in hwmon 1264 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1265 temperature and allows controlling fan speeds of Dell laptops via 1266 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1267 it reports also power and hotkey status. For fan speed control is 1268 needed userspace package i8kutils. 1269 1270 Say Y if you intend to run this kernel on old Dell laptops or want to 1271 use userspace package i8kutils. 1272 Say N otherwise. 1273 1274config X86_REBOOTFIXUPS 1275 bool "Enable X86 board specific fixups for reboot" 1276 depends on X86_32 1277 help 1278 This enables chipset and/or board specific fixups to be done 1279 in order to get reboot to work correctly. This is only needed on 1280 some combinations of hardware and BIOS. The symptom, for which 1281 this config is intended, is when reboot ends with a stalled/hung 1282 system. 1283 1284 Currently, the only fixup is for the Geode machines using 1285 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1286 1287 Say Y if you want to enable the fixup. Currently, it's safe to 1288 enable this option even if you don't need it. 1289 Say N otherwise. 1290 1291config MICROCODE 1292 bool "CPU microcode loading support" 1293 default y 1294 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1295 help 1296 If you say Y here, you will be able to update the microcode on 1297 Intel and AMD processors. The Intel support is for the IA32 family, 1298 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1299 AMD support is for families 0x10 and later. You will obviously need 1300 the actual microcode binary data itself which is not shipped with 1301 the Linux kernel. 1302 1303 The preferred method to load microcode from a detached initrd is described 1304 in Documentation/x86/microcode.rst. For that you need to enable 1305 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1306 initrd for microcode blobs. 1307 1308 In addition, you can build the microcode into the kernel. For that you 1309 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1310 config option. 1311 1312config MICROCODE_INTEL 1313 bool "Intel microcode loading support" 1314 depends on MICROCODE 1315 default MICROCODE 1316 help 1317 This options enables microcode patch loading support for Intel 1318 processors. 1319 1320 For the current Intel microcode data package go to 1321 <https://downloadcenter.intel.com> and search for 1322 'Linux Processor Microcode Data File'. 1323 1324config MICROCODE_AMD 1325 bool "AMD microcode loading support" 1326 depends on MICROCODE 1327 help 1328 If you select this option, microcode patch loading support for AMD 1329 processors will be enabled. 1330 1331config MICROCODE_OLD_INTERFACE 1332 bool "Ancient loading interface (DEPRECATED)" 1333 default n 1334 depends on MICROCODE 1335 help 1336 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1337 which was used by userspace tools like iucode_tool and microcode.ctl. 1338 It is inadequate because it runs too late to be able to properly 1339 load microcode on a machine and it needs special tools. Instead, you 1340 should've switched to the early loading method with the initrd or 1341 builtin microcode by now: Documentation/x86/microcode.rst 1342 1343config X86_MSR 1344 tristate "/dev/cpu/*/msr - Model-specific register support" 1345 help 1346 This device gives privileged processes access to the x86 1347 Model-Specific Registers (MSRs). It is a character device with 1348 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1349 MSR accesses are directed to a specific CPU on multi-processor 1350 systems. 1351 1352config X86_CPUID 1353 tristate "/dev/cpu/*/cpuid - CPU information support" 1354 help 1355 This device gives processes access to the x86 CPUID instruction to 1356 be executed on a specific processor. It is a character device 1357 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1358 /dev/cpu/31/cpuid. 1359 1360choice 1361 prompt "High Memory Support" 1362 default HIGHMEM4G 1363 depends on X86_32 1364 1365config NOHIGHMEM 1366 bool "off" 1367 help 1368 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1369 However, the address space of 32-bit x86 processors is only 4 1370 Gigabytes large. That means that, if you have a large amount of 1371 physical memory, not all of it can be "permanently mapped" by the 1372 kernel. The physical memory that's not permanently mapped is called 1373 "high memory". 1374 1375 If you are compiling a kernel which will never run on a machine with 1376 more than 1 Gigabyte total physical RAM, answer "off" here (default 1377 choice and suitable for most users). This will result in a "3GB/1GB" 1378 split: 3GB are mapped so that each process sees a 3GB virtual memory 1379 space and the remaining part of the 4GB virtual memory space is used 1380 by the kernel to permanently map as much physical memory as 1381 possible. 1382 1383 If the machine has between 1 and 4 Gigabytes physical RAM, then 1384 answer "4GB" here. 1385 1386 If more than 4 Gigabytes is used then answer "64GB" here. This 1387 selection turns Intel PAE (Physical Address Extension) mode on. 1388 PAE implements 3-level paging on IA32 processors. PAE is fully 1389 supported by Linux, PAE mode is implemented on all recent Intel 1390 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1391 then the kernel will not boot on CPUs that don't support PAE! 1392 1393 The actual amount of total physical memory will either be 1394 auto detected or can be forced by using a kernel command line option 1395 such as "mem=256M". (Try "man bootparam" or see the documentation of 1396 your boot loader (lilo or loadlin) about how to pass options to the 1397 kernel at boot time.) 1398 1399 If unsure, say "off". 1400 1401config HIGHMEM4G 1402 bool "4GB" 1403 help 1404 Select this if you have a 32-bit processor and between 1 and 4 1405 gigabytes of physical RAM. 1406 1407config HIGHMEM64G 1408 bool "64GB" 1409 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1410 select X86_PAE 1411 help 1412 Select this if you have a 32-bit processor and more than 4 1413 gigabytes of physical RAM. 1414 1415endchoice 1416 1417choice 1418 prompt "Memory split" if EXPERT 1419 default VMSPLIT_3G 1420 depends on X86_32 1421 help 1422 Select the desired split between kernel and user memory. 1423 1424 If the address range available to the kernel is less than the 1425 physical memory installed, the remaining memory will be available 1426 as "high memory". Accessing high memory is a little more costly 1427 than low memory, as it needs to be mapped into the kernel first. 1428 Note that increasing the kernel address space limits the range 1429 available to user programs, making the address space there 1430 tighter. Selecting anything other than the default 3G/1G split 1431 will also likely make your kernel incompatible with binary-only 1432 kernel modules. 1433 1434 If you are not absolutely sure what you are doing, leave this 1435 option alone! 1436 1437 config VMSPLIT_3G 1438 bool "3G/1G user/kernel split" 1439 config VMSPLIT_3G_OPT 1440 depends on !X86_PAE 1441 bool "3G/1G user/kernel split (for full 1G low memory)" 1442 config VMSPLIT_2G 1443 bool "2G/2G user/kernel split" 1444 config VMSPLIT_2G_OPT 1445 depends on !X86_PAE 1446 bool "2G/2G user/kernel split (for full 2G low memory)" 1447 config VMSPLIT_1G 1448 bool "1G/3G user/kernel split" 1449endchoice 1450 1451config PAGE_OFFSET 1452 hex 1453 default 0xB0000000 if VMSPLIT_3G_OPT 1454 default 0x80000000 if VMSPLIT_2G 1455 default 0x78000000 if VMSPLIT_2G_OPT 1456 default 0x40000000 if VMSPLIT_1G 1457 default 0xC0000000 1458 depends on X86_32 1459 1460config HIGHMEM 1461 def_bool y 1462 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1463 1464config X86_PAE 1465 bool "PAE (Physical Address Extension) Support" 1466 depends on X86_32 && !HIGHMEM4G 1467 select PHYS_ADDR_T_64BIT 1468 select SWIOTLB 1469 help 1470 PAE is required for NX support, and furthermore enables 1471 larger swapspace support for non-overcommit purposes. It 1472 has the cost of more pagetable lookup overhead, and also 1473 consumes more pagetable space per process. 1474 1475config X86_5LEVEL 1476 bool "Enable 5-level page tables support" 1477 default y 1478 select DYNAMIC_MEMORY_LAYOUT 1479 select SPARSEMEM_VMEMMAP 1480 depends on X86_64 1481 help 1482 5-level paging enables access to larger address space: 1483 upto 128 PiB of virtual address space and 4 PiB of 1484 physical address space. 1485 1486 It will be supported by future Intel CPUs. 1487 1488 A kernel with the option enabled can be booted on machines that 1489 support 4- or 5-level paging. 1490 1491 See Documentation/x86/x86_64/5level-paging.rst for more 1492 information. 1493 1494 Say N if unsure. 1495 1496config X86_DIRECT_GBPAGES 1497 def_bool y 1498 depends on X86_64 1499 help 1500 Certain kernel features effectively disable kernel 1501 linear 1 GB mappings (even if the CPU otherwise 1502 supports them), so don't confuse the user by printing 1503 that we have them enabled. 1504 1505config X86_CPA_STATISTICS 1506 bool "Enable statistic for Change Page Attribute" 1507 depends on DEBUG_FS 1508 help 1509 Expose statistics about the Change Page Attribute mechanism, which 1510 helps to determine the effectiveness of preserving large and huge 1511 page mappings when mapping protections are changed. 1512 1513config AMD_MEM_ENCRYPT 1514 bool "AMD Secure Memory Encryption (SME) support" 1515 depends on X86_64 && CPU_SUP_AMD 1516 select DMA_COHERENT_POOL 1517 select DYNAMIC_PHYSICAL_MASK 1518 select ARCH_USE_MEMREMAP_PROT 1519 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1520 select INSTRUCTION_DECODER 1521 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 1522 help 1523 Say yes to enable support for the encryption of system memory. 1524 This requires an AMD processor that supports Secure Memory 1525 Encryption (SME). 1526 1527config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1528 bool "Activate AMD Secure Memory Encryption (SME) by default" 1529 default y 1530 depends on AMD_MEM_ENCRYPT 1531 help 1532 Say yes to have system memory encrypted by default if running on 1533 an AMD processor that supports Secure Memory Encryption (SME). 1534 1535 If set to Y, then the encryption of system memory can be 1536 deactivated with the mem_encrypt=off command line option. 1537 1538 If set to N, then the encryption of system memory can be 1539 activated with the mem_encrypt=on command line option. 1540 1541# Common NUMA Features 1542config NUMA 1543 bool "NUMA Memory Allocation and Scheduler Support" 1544 depends on SMP 1545 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1546 default y if X86_BIGSMP 1547 help 1548 Enable NUMA (Non-Uniform Memory Access) support. 1549 1550 The kernel will try to allocate memory used by a CPU on the 1551 local memory controller of the CPU and add some more 1552 NUMA awareness to the kernel. 1553 1554 For 64-bit this is recommended if the system is Intel Core i7 1555 (or later), AMD Opteron, or EM64T NUMA. 1556 1557 For 32-bit this is only needed if you boot a 32-bit 1558 kernel on a 64-bit NUMA platform. 1559 1560 Otherwise, you should say N. 1561 1562config AMD_NUMA 1563 def_bool y 1564 prompt "Old style AMD Opteron NUMA detection" 1565 depends on X86_64 && NUMA && PCI 1566 help 1567 Enable AMD NUMA node topology detection. You should say Y here if 1568 you have a multi processor AMD system. This uses an old method to 1569 read the NUMA configuration directly from the builtin Northbridge 1570 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1571 which also takes priority if both are compiled in. 1572 1573config X86_64_ACPI_NUMA 1574 def_bool y 1575 prompt "ACPI NUMA detection" 1576 depends on X86_64 && NUMA && ACPI && PCI 1577 select ACPI_NUMA 1578 help 1579 Enable ACPI SRAT based node topology detection. 1580 1581config NUMA_EMU 1582 bool "NUMA emulation" 1583 depends on NUMA 1584 help 1585 Enable NUMA emulation. A flat machine will be split 1586 into virtual nodes when booted with "numa=fake=N", where N is the 1587 number of nodes. This is only useful for debugging. 1588 1589config NODES_SHIFT 1590 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1591 range 1 10 1592 default "10" if MAXSMP 1593 default "6" if X86_64 1594 default "3" 1595 depends on NUMA 1596 help 1597 Specify the maximum number of NUMA Nodes available on the target 1598 system. Increases memory reserved to accommodate various tables. 1599 1600config ARCH_FLATMEM_ENABLE 1601 def_bool y 1602 depends on X86_32 && !NUMA 1603 1604config ARCH_SPARSEMEM_ENABLE 1605 def_bool y 1606 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1607 select SPARSEMEM_STATIC if X86_32 1608 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1609 1610config ARCH_SPARSEMEM_DEFAULT 1611 def_bool X86_64 || (NUMA && X86_32) 1612 1613config ARCH_SELECT_MEMORY_MODEL 1614 def_bool y 1615 depends on ARCH_SPARSEMEM_ENABLE 1616 1617config ARCH_MEMORY_PROBE 1618 bool "Enable sysfs memory/probe interface" 1619 depends on X86_64 && MEMORY_HOTPLUG 1620 help 1621 This option enables a sysfs memory/probe interface for testing. 1622 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1623 If you are unsure how to answer this question, answer N. 1624 1625config ARCH_PROC_KCORE_TEXT 1626 def_bool y 1627 depends on X86_64 && PROC_KCORE 1628 1629config ILLEGAL_POINTER_VALUE 1630 hex 1631 default 0 if X86_32 1632 default 0xdead000000000000 if X86_64 1633 1634config X86_PMEM_LEGACY_DEVICE 1635 bool 1636 1637config X86_PMEM_LEGACY 1638 tristate "Support non-standard NVDIMMs and ADR protected memory" 1639 depends on PHYS_ADDR_T_64BIT 1640 depends on BLK_DEV 1641 select X86_PMEM_LEGACY_DEVICE 1642 select NUMA_KEEP_MEMINFO if NUMA 1643 select LIBNVDIMM 1644 help 1645 Treat memory marked using the non-standard e820 type of 12 as used 1646 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1647 The kernel will offer these regions to the 'pmem' driver so 1648 they can be used for persistent storage. 1649 1650 Say Y if unsure. 1651 1652config HIGHPTE 1653 bool "Allocate 3rd-level pagetables from highmem" 1654 depends on HIGHMEM 1655 help 1656 The VM uses one page table entry for each page of physical memory. 1657 For systems with a lot of RAM, this can be wasteful of precious 1658 low memory. Setting this option will put user-space page table 1659 entries in high memory. 1660 1661config X86_CHECK_BIOS_CORRUPTION 1662 bool "Check for low memory corruption" 1663 help 1664 Periodically check for memory corruption in low memory, which 1665 is suspected to be caused by BIOS. Even when enabled in the 1666 configuration, it is disabled at runtime. Enable it by 1667 setting "memory_corruption_check=1" on the kernel command 1668 line. By default it scans the low 64k of memory every 60 1669 seconds; see the memory_corruption_check_size and 1670 memory_corruption_check_period parameters in 1671 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1672 1673 When enabled with the default parameters, this option has 1674 almost no overhead, as it reserves a relatively small amount 1675 of memory and scans it infrequently. It both detects corruption 1676 and prevents it from affecting the running system. 1677 1678 It is, however, intended as a diagnostic tool; if repeatable 1679 BIOS-originated corruption always affects the same memory, 1680 you can use memmap= to prevent the kernel from using that 1681 memory. 1682 1683config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1684 bool "Set the default setting of memory_corruption_check" 1685 depends on X86_CHECK_BIOS_CORRUPTION 1686 default y 1687 help 1688 Set whether the default state of memory_corruption_check is 1689 on or off. 1690 1691config MATH_EMULATION 1692 bool 1693 depends on MODIFY_LDT_SYSCALL 1694 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1695 help 1696 Linux can emulate a math coprocessor (used for floating point 1697 operations) if you don't have one. 486DX and Pentium processors have 1698 a math coprocessor built in, 486SX and 386 do not, unless you added 1699 a 487DX or 387, respectively. (The messages during boot time can 1700 give you some hints here ["man dmesg"].) Everyone needs either a 1701 coprocessor or this emulation. 1702 1703 If you don't have a math coprocessor, you need to say Y here; if you 1704 say Y here even though you have a coprocessor, the coprocessor will 1705 be used nevertheless. (This behavior can be changed with the kernel 1706 command line option "no387", which comes handy if your coprocessor 1707 is broken. Try "man bootparam" or see the documentation of your boot 1708 loader (lilo or loadlin) about how to pass options to the kernel at 1709 boot time.) This means that it is a good idea to say Y here if you 1710 intend to use this kernel on different machines. 1711 1712 More information about the internals of the Linux math coprocessor 1713 emulation can be found in <file:arch/x86/math-emu/README>. 1714 1715 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1716 kernel, it won't hurt. 1717 1718config MTRR 1719 def_bool y 1720 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1721 help 1722 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1723 the Memory Type Range Registers (MTRRs) may be used to control 1724 processor access to memory ranges. This is most useful if you have 1725 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1726 allows bus write transfers to be combined into a larger transfer 1727 before bursting over the PCI/AGP bus. This can increase performance 1728 of image write operations 2.5 times or more. Saying Y here creates a 1729 /proc/mtrr file which may be used to manipulate your processor's 1730 MTRRs. Typically the X server should use this. 1731 1732 This code has a reasonably generic interface so that similar 1733 control registers on other processors can be easily supported 1734 as well: 1735 1736 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1737 Registers (ARRs) which provide a similar functionality to MTRRs. For 1738 these, the ARRs are used to emulate the MTRRs. 1739 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1740 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1741 write-combining. All of these processors are supported by this code 1742 and it makes sense to say Y here if you have one of them. 1743 1744 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1745 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1746 can lead to all sorts of problems, so it's good to say Y here. 1747 1748 You can safely say Y even if your machine doesn't have MTRRs, you'll 1749 just add about 9 KB to your kernel. 1750 1751 See <file:Documentation/x86/mtrr.rst> for more information. 1752 1753config MTRR_SANITIZER 1754 def_bool y 1755 prompt "MTRR cleanup support" 1756 depends on MTRR 1757 help 1758 Convert MTRR layout from continuous to discrete, so X drivers can 1759 add writeback entries. 1760 1761 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1762 The largest mtrr entry size for a continuous block can be set with 1763 mtrr_chunk_size. 1764 1765 If unsure, say Y. 1766 1767config MTRR_SANITIZER_ENABLE_DEFAULT 1768 int "MTRR cleanup enable value (0-1)" 1769 range 0 1 1770 default "0" 1771 depends on MTRR_SANITIZER 1772 help 1773 Enable mtrr cleanup default value 1774 1775config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1776 int "MTRR cleanup spare reg num (0-7)" 1777 range 0 7 1778 default "1" 1779 depends on MTRR_SANITIZER 1780 help 1781 mtrr cleanup spare entries default, it can be changed via 1782 mtrr_spare_reg_nr=N on the kernel command line. 1783 1784config X86_PAT 1785 def_bool y 1786 prompt "x86 PAT support" if EXPERT 1787 depends on MTRR 1788 help 1789 Use PAT attributes to setup page level cache control. 1790 1791 PATs are the modern equivalents of MTRRs and are much more 1792 flexible than MTRRs. 1793 1794 Say N here if you see bootup problems (boot crash, boot hang, 1795 spontaneous reboots) or a non-working video driver. 1796 1797 If unsure, say Y. 1798 1799config ARCH_USES_PG_UNCACHED 1800 def_bool y 1801 depends on X86_PAT 1802 1803config ARCH_RANDOM 1804 def_bool y 1805 prompt "x86 architectural random number generator" if EXPERT 1806 help 1807 Enable the x86 architectural RDRAND instruction 1808 (Intel Bull Mountain technology) to generate random numbers. 1809 If supported, this is a high bandwidth, cryptographically 1810 secure hardware random number generator. 1811 1812config X86_SMAP 1813 def_bool y 1814 prompt "Supervisor Mode Access Prevention" if EXPERT 1815 help 1816 Supervisor Mode Access Prevention (SMAP) is a security 1817 feature in newer Intel processors. There is a small 1818 performance cost if this enabled and turned on; there is 1819 also a small increase in the kernel size if this is enabled. 1820 1821 If unsure, say Y. 1822 1823config X86_UMIP 1824 def_bool y 1825 prompt "User Mode Instruction Prevention" if EXPERT 1826 help 1827 User Mode Instruction Prevention (UMIP) is a security feature in 1828 some x86 processors. If enabled, a general protection fault is 1829 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1830 executed in user mode. These instructions unnecessarily expose 1831 information about the hardware state. 1832 1833 The vast majority of applications do not use these instructions. 1834 For the very few that do, software emulation is provided in 1835 specific cases in protected and virtual-8086 modes. Emulated 1836 results are dummy. 1837 1838config X86_INTEL_MEMORY_PROTECTION_KEYS 1839 prompt "Memory Protection Keys" 1840 def_bool y 1841 # Note: only available in 64-bit mode 1842 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1843 select ARCH_USES_HIGH_VMA_FLAGS 1844 select ARCH_HAS_PKEYS 1845 help 1846 Memory Protection Keys provides a mechanism for enforcing 1847 page-based protections, but without requiring modification of the 1848 page tables when an application changes protection domains. 1849 1850 For details, see Documentation/core-api/protection-keys.rst 1851 1852 If unsure, say y. 1853 1854choice 1855 prompt "TSX enable mode" 1856 depends on CPU_SUP_INTEL 1857 default X86_INTEL_TSX_MODE_OFF 1858 help 1859 Intel's TSX (Transactional Synchronization Extensions) feature 1860 allows to optimize locking protocols through lock elision which 1861 can lead to a noticeable performance boost. 1862 1863 On the other hand it has been shown that TSX can be exploited 1864 to form side channel attacks (e.g. TAA) and chances are there 1865 will be more of those attacks discovered in the future. 1866 1867 Therefore TSX is not enabled by default (aka tsx=off). An admin 1868 might override this decision by tsx=on the command line parameter. 1869 Even with TSX enabled, the kernel will attempt to enable the best 1870 possible TAA mitigation setting depending on the microcode available 1871 for the particular machine. 1872 1873 This option allows to set the default tsx mode between tsx=on, =off 1874 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1875 details. 1876 1877 Say off if not sure, auto if TSX is in use but it should be used on safe 1878 platforms or on if TSX is in use and the security aspect of tsx is not 1879 relevant. 1880 1881config X86_INTEL_TSX_MODE_OFF 1882 bool "off" 1883 help 1884 TSX is disabled if possible - equals to tsx=off command line parameter. 1885 1886config X86_INTEL_TSX_MODE_ON 1887 bool "on" 1888 help 1889 TSX is always enabled on TSX capable HW - equals the tsx=on command 1890 line parameter. 1891 1892config X86_INTEL_TSX_MODE_AUTO 1893 bool "auto" 1894 help 1895 TSX is enabled on TSX capable HW that is believed to be safe against 1896 side channel attacks- equals the tsx=auto command line parameter. 1897endchoice 1898 1899config X86_SGX 1900 bool "Software Guard eXtensions (SGX)" 1901 depends on X86_64 && CPU_SUP_INTEL 1902 depends on CRYPTO=y 1903 depends on CRYPTO_SHA256=y 1904 select SRCU 1905 select MMU_NOTIFIER 1906 select NUMA_KEEP_MEMINFO if NUMA 1907 help 1908 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1909 that can be used by applications to set aside private regions of code 1910 and data, referred to as enclaves. An enclave's private memory can 1911 only be accessed by code running within the enclave. Accesses from 1912 outside the enclave, including other enclaves, are disallowed by 1913 hardware. 1914 1915 If unsure, say N. 1916 1917config EFI 1918 bool "EFI runtime service support" 1919 depends on ACPI 1920 select UCS2_STRING 1921 select EFI_RUNTIME_WRAPPERS 1922 help 1923 This enables the kernel to use EFI runtime services that are 1924 available (such as the EFI variable services). 1925 1926 This option is only useful on systems that have EFI firmware. 1927 In addition, you should use the latest ELILO loader available 1928 at <http://elilo.sourceforge.net> in order to take advantage 1929 of EFI runtime services. However, even with this option, the 1930 resultant kernel should continue to boot on existing non-EFI 1931 platforms. 1932 1933config EFI_STUB 1934 bool "EFI stub support" 1935 depends on EFI && !X86_USE_3DNOW 1936 depends on $(cc-option,-mabi=ms) || X86_32 1937 select RELOCATABLE 1938 help 1939 This kernel feature allows a bzImage to be loaded directly 1940 by EFI firmware without the use of a bootloader. 1941 1942 See Documentation/admin-guide/efi-stub.rst for more information. 1943 1944config EFI_MIXED 1945 bool "EFI mixed-mode support" 1946 depends on EFI_STUB && X86_64 1947 help 1948 Enabling this feature allows a 64-bit kernel to be booted 1949 on a 32-bit firmware, provided that your CPU supports 64-bit 1950 mode. 1951 1952 Note that it is not possible to boot a mixed-mode enabled 1953 kernel via the EFI boot stub - a bootloader that supports 1954 the EFI handover protocol must be used. 1955 1956 If unsure, say N. 1957 1958source "kernel/Kconfig.hz" 1959 1960config KEXEC 1961 bool "kexec system call" 1962 select KEXEC_CORE 1963 help 1964 kexec is a system call that implements the ability to shutdown your 1965 current kernel, and to start another kernel. It is like a reboot 1966 but it is independent of the system firmware. And like a reboot 1967 you can start any kernel with it, not just Linux. 1968 1969 The name comes from the similarity to the exec system call. 1970 1971 It is an ongoing process to be certain the hardware in a machine 1972 is properly shutdown, so do not be surprised if this code does not 1973 initially work for you. As of this writing the exact hardware 1974 interface is strongly in flux, so no good recommendation can be 1975 made. 1976 1977config KEXEC_FILE 1978 bool "kexec file based system call" 1979 select KEXEC_CORE 1980 select BUILD_BIN2C 1981 depends on X86_64 1982 depends on CRYPTO=y 1983 depends on CRYPTO_SHA256=y 1984 help 1985 This is new version of kexec system call. This system call is 1986 file based and takes file descriptors as system call argument 1987 for kernel and initramfs as opposed to list of segments as 1988 accepted by previous system call. 1989 1990config ARCH_HAS_KEXEC_PURGATORY 1991 def_bool KEXEC_FILE 1992 1993config KEXEC_SIG 1994 bool "Verify kernel signature during kexec_file_load() syscall" 1995 depends on KEXEC_FILE 1996 help 1997 1998 This option makes the kexec_file_load() syscall check for a valid 1999 signature of the kernel image. The image can still be loaded without 2000 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2001 there's a signature that we can check, then it must be valid. 2002 2003 In addition to this option, you need to enable signature 2004 verification for the corresponding kernel image type being 2005 loaded in order for this to work. 2006 2007config KEXEC_SIG_FORCE 2008 bool "Require a valid signature in kexec_file_load() syscall" 2009 depends on KEXEC_SIG 2010 help 2011 This option makes kernel signature verification mandatory for 2012 the kexec_file_load() syscall. 2013 2014config KEXEC_BZIMAGE_VERIFY_SIG 2015 bool "Enable bzImage signature verification support" 2016 depends on KEXEC_SIG 2017 depends on SIGNED_PE_FILE_VERIFICATION 2018 select SYSTEM_TRUSTED_KEYRING 2019 help 2020 Enable bzImage signature verification support. 2021 2022config CRASH_DUMP 2023 bool "kernel crash dumps" 2024 depends on X86_64 || (X86_32 && HIGHMEM) 2025 help 2026 Generate crash dump after being started by kexec. 2027 This should be normally only set in special crash dump kernels 2028 which are loaded in the main kernel with kexec-tools into 2029 a specially reserved region and then later executed after 2030 a crash by kdump/kexec. The crash dump kernel must be compiled 2031 to a memory address not used by the main kernel or BIOS using 2032 PHYSICAL_START, or it must be built as a relocatable image 2033 (CONFIG_RELOCATABLE=y). 2034 For more details see Documentation/admin-guide/kdump/kdump.rst 2035 2036config KEXEC_JUMP 2037 bool "kexec jump" 2038 depends on KEXEC && HIBERNATION 2039 help 2040 Jump between original kernel and kexeced kernel and invoke 2041 code in physical address mode via KEXEC 2042 2043config PHYSICAL_START 2044 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2045 default "0x1000000" 2046 help 2047 This gives the physical address where the kernel is loaded. 2048 2049 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2050 bzImage will decompress itself to above physical address and 2051 run from there. Otherwise, bzImage will run from the address where 2052 it has been loaded by the boot loader and will ignore above physical 2053 address. 2054 2055 In normal kdump cases one does not have to set/change this option 2056 as now bzImage can be compiled as a completely relocatable image 2057 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2058 address. This option is mainly useful for the folks who don't want 2059 to use a bzImage for capturing the crash dump and want to use a 2060 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2061 to be specifically compiled to run from a specific memory area 2062 (normally a reserved region) and this option comes handy. 2063 2064 So if you are using bzImage for capturing the crash dump, 2065 leave the value here unchanged to 0x1000000 and set 2066 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2067 for capturing the crash dump change this value to start of 2068 the reserved region. In other words, it can be set based on 2069 the "X" value as specified in the "crashkernel=YM@XM" 2070 command line boot parameter passed to the panic-ed 2071 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2072 for more details about crash dumps. 2073 2074 Usage of bzImage for capturing the crash dump is recommended as 2075 one does not have to build two kernels. Same kernel can be used 2076 as production kernel and capture kernel. Above option should have 2077 gone away after relocatable bzImage support is introduced. But it 2078 is present because there are users out there who continue to use 2079 vmlinux for dump capture. This option should go away down the 2080 line. 2081 2082 Don't change this unless you know what you are doing. 2083 2084config RELOCATABLE 2085 bool "Build a relocatable kernel" 2086 default y 2087 help 2088 This builds a kernel image that retains relocation information 2089 so it can be loaded someplace besides the default 1MB. 2090 The relocations tend to make the kernel binary about 10% larger, 2091 but are discarded at runtime. 2092 2093 One use is for the kexec on panic case where the recovery kernel 2094 must live at a different physical address than the primary 2095 kernel. 2096 2097 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2098 it has been loaded at and the compile time physical address 2099 (CONFIG_PHYSICAL_START) is used as the minimum location. 2100 2101config RANDOMIZE_BASE 2102 bool "Randomize the address of the kernel image (KASLR)" 2103 depends on RELOCATABLE 2104 default y 2105 help 2106 In support of Kernel Address Space Layout Randomization (KASLR), 2107 this randomizes the physical address at which the kernel image 2108 is decompressed and the virtual address where the kernel 2109 image is mapped, as a security feature that deters exploit 2110 attempts relying on knowledge of the location of kernel 2111 code internals. 2112 2113 On 64-bit, the kernel physical and virtual addresses are 2114 randomized separately. The physical address will be anywhere 2115 between 16MB and the top of physical memory (up to 64TB). The 2116 virtual address will be randomized from 16MB up to 1GB (9 bits 2117 of entropy). Note that this also reduces the memory space 2118 available to kernel modules from 1.5GB to 1GB. 2119 2120 On 32-bit, the kernel physical and virtual addresses are 2121 randomized together. They will be randomized from 16MB up to 2122 512MB (8 bits of entropy). 2123 2124 Entropy is generated using the RDRAND instruction if it is 2125 supported. If RDTSC is supported, its value is mixed into 2126 the entropy pool as well. If neither RDRAND nor RDTSC are 2127 supported, then entropy is read from the i8254 timer. The 2128 usable entropy is limited by the kernel being built using 2129 2GB addressing, and that PHYSICAL_ALIGN must be at a 2130 minimum of 2MB. As a result, only 10 bits of entropy are 2131 theoretically possible, but the implementations are further 2132 limited due to memory layouts. 2133 2134 If unsure, say Y. 2135 2136# Relocation on x86 needs some additional build support 2137config X86_NEED_RELOCS 2138 def_bool y 2139 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2140 2141config PHYSICAL_ALIGN 2142 hex "Alignment value to which kernel should be aligned" 2143 default "0x200000" 2144 range 0x2000 0x1000000 if X86_32 2145 range 0x200000 0x1000000 if X86_64 2146 help 2147 This value puts the alignment restrictions on physical address 2148 where kernel is loaded and run from. Kernel is compiled for an 2149 address which meets above alignment restriction. 2150 2151 If bootloader loads the kernel at a non-aligned address and 2152 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2153 address aligned to above value and run from there. 2154 2155 If bootloader loads the kernel at a non-aligned address and 2156 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2157 load address and decompress itself to the address it has been 2158 compiled for and run from there. The address for which kernel is 2159 compiled already meets above alignment restrictions. Hence the 2160 end result is that kernel runs from a physical address meeting 2161 above alignment restrictions. 2162 2163 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2164 this value must be a multiple of 0x200000. 2165 2166 Don't change this unless you know what you are doing. 2167 2168config DYNAMIC_MEMORY_LAYOUT 2169 bool 2170 help 2171 This option makes base addresses of vmalloc and vmemmap as well as 2172 __PAGE_OFFSET movable during boot. 2173 2174config RANDOMIZE_MEMORY 2175 bool "Randomize the kernel memory sections" 2176 depends on X86_64 2177 depends on RANDOMIZE_BASE 2178 select DYNAMIC_MEMORY_LAYOUT 2179 default RANDOMIZE_BASE 2180 help 2181 Randomizes the base virtual address of kernel memory sections 2182 (physical memory mapping, vmalloc & vmemmap). This security feature 2183 makes exploits relying on predictable memory locations less reliable. 2184 2185 The order of allocations remains unchanged. Entropy is generated in 2186 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2187 configuration have in average 30,000 different possible virtual 2188 addresses for each memory section. 2189 2190 If unsure, say Y. 2191 2192config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2193 hex "Physical memory mapping padding" if EXPERT 2194 depends on RANDOMIZE_MEMORY 2195 default "0xa" if MEMORY_HOTPLUG 2196 default "0x0" 2197 range 0x1 0x40 if MEMORY_HOTPLUG 2198 range 0x0 0x40 2199 help 2200 Define the padding in terabytes added to the existing physical 2201 memory size during kernel memory randomization. It is useful 2202 for memory hotplug support but reduces the entropy available for 2203 address randomization. 2204 2205 If unsure, leave at the default value. 2206 2207config HOTPLUG_CPU 2208 def_bool y 2209 depends on SMP 2210 2211config BOOTPARAM_HOTPLUG_CPU0 2212 bool "Set default setting of cpu0_hotpluggable" 2213 depends on HOTPLUG_CPU 2214 help 2215 Set whether default state of cpu0_hotpluggable is on or off. 2216 2217 Say Y here to enable CPU0 hotplug by default. If this switch 2218 is turned on, there is no need to give cpu0_hotplug kernel 2219 parameter and the CPU0 hotplug feature is enabled by default. 2220 2221 Please note: there are two known CPU0 dependencies if you want 2222 to enable the CPU0 hotplug feature either by this switch or by 2223 cpu0_hotplug kernel parameter. 2224 2225 First, resume from hibernate or suspend always starts from CPU0. 2226 So hibernate and suspend are prevented if CPU0 is offline. 2227 2228 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2229 offline if any interrupt can not migrate out of CPU0. There may 2230 be other CPU0 dependencies. 2231 2232 Please make sure the dependencies are under your control before 2233 you enable this feature. 2234 2235 Say N if you don't want to enable CPU0 hotplug feature by default. 2236 You still can enable the CPU0 hotplug feature at boot by kernel 2237 parameter cpu0_hotplug. 2238 2239config DEBUG_HOTPLUG_CPU0 2240 def_bool n 2241 prompt "Debug CPU0 hotplug" 2242 depends on HOTPLUG_CPU 2243 help 2244 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2245 soon as possible and boots up userspace with CPU0 offlined. User 2246 can online CPU0 back after boot time. 2247 2248 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2249 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2250 compilation or giving cpu0_hotplug kernel parameter at boot. 2251 2252 If unsure, say N. 2253 2254config COMPAT_VDSO 2255 def_bool n 2256 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2257 depends on COMPAT_32 2258 help 2259 Certain buggy versions of glibc will crash if they are 2260 presented with a 32-bit vDSO that is not mapped at the address 2261 indicated in its segment table. 2262 2263 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2264 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2265 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2266 the only released version with the bug, but OpenSUSE 9 2267 contains a buggy "glibc 2.3.2". 2268 2269 The symptom of the bug is that everything crashes on startup, saying: 2270 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2271 2272 Saying Y here changes the default value of the vdso32 boot 2273 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2274 This works around the glibc bug but hurts performance. 2275 2276 If unsure, say N: if you are compiling your own kernel, you 2277 are unlikely to be using a buggy version of glibc. 2278 2279choice 2280 prompt "vsyscall table for legacy applications" 2281 depends on X86_64 2282 default LEGACY_VSYSCALL_XONLY 2283 help 2284 Legacy user code that does not know how to find the vDSO expects 2285 to be able to issue three syscalls by calling fixed addresses in 2286 kernel space. Since this location is not randomized with ASLR, 2287 it can be used to assist security vulnerability exploitation. 2288 2289 This setting can be changed at boot time via the kernel command 2290 line parameter vsyscall=[emulate|xonly|none]. 2291 2292 On a system with recent enough glibc (2.14 or newer) and no 2293 static binaries, you can say None without a performance penalty 2294 to improve security. 2295 2296 If unsure, select "Emulate execution only". 2297 2298 config LEGACY_VSYSCALL_EMULATE 2299 bool "Full emulation" 2300 help 2301 The kernel traps and emulates calls into the fixed vsyscall 2302 address mapping. This makes the mapping non-executable, but 2303 it still contains readable known contents, which could be 2304 used in certain rare security vulnerability exploits. This 2305 configuration is recommended when using legacy userspace 2306 that still uses vsyscalls along with legacy binary 2307 instrumentation tools that require code to be readable. 2308 2309 An example of this type of legacy userspace is running 2310 Pin on an old binary that still uses vsyscalls. 2311 2312 config LEGACY_VSYSCALL_XONLY 2313 bool "Emulate execution only" 2314 help 2315 The kernel traps and emulates calls into the fixed vsyscall 2316 address mapping and does not allow reads. This 2317 configuration is recommended when userspace might use the 2318 legacy vsyscall area but support for legacy binary 2319 instrumentation of legacy code is not needed. It mitigates 2320 certain uses of the vsyscall area as an ASLR-bypassing 2321 buffer. 2322 2323 config LEGACY_VSYSCALL_NONE 2324 bool "None" 2325 help 2326 There will be no vsyscall mapping at all. This will 2327 eliminate any risk of ASLR bypass due to the vsyscall 2328 fixed address mapping. Attempts to use the vsyscalls 2329 will be reported to dmesg, so that either old or 2330 malicious userspace programs can be identified. 2331 2332endchoice 2333 2334config CMDLINE_BOOL 2335 bool "Built-in kernel command line" 2336 help 2337 Allow for specifying boot arguments to the kernel at 2338 build time. On some systems (e.g. embedded ones), it is 2339 necessary or convenient to provide some or all of the 2340 kernel boot arguments with the kernel itself (that is, 2341 to not rely on the boot loader to provide them.) 2342 2343 To compile command line arguments into the kernel, 2344 set this option to 'Y', then fill in the 2345 boot arguments in CONFIG_CMDLINE. 2346 2347 Systems with fully functional boot loaders (i.e. non-embedded) 2348 should leave this option set to 'N'. 2349 2350config CMDLINE 2351 string "Built-in kernel command string" 2352 depends on CMDLINE_BOOL 2353 default "" 2354 help 2355 Enter arguments here that should be compiled into the kernel 2356 image and used at boot time. If the boot loader provides a 2357 command line at boot time, it is appended to this string to 2358 form the full kernel command line, when the system boots. 2359 2360 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2361 change this behavior. 2362 2363 In most cases, the command line (whether built-in or provided 2364 by the boot loader) should specify the device for the root 2365 file system. 2366 2367config CMDLINE_OVERRIDE 2368 bool "Built-in command line overrides boot loader arguments" 2369 depends on CMDLINE_BOOL && CMDLINE != "" 2370 help 2371 Set this option to 'Y' to have the kernel ignore the boot loader 2372 command line, and use ONLY the built-in command line. 2373 2374 This is used to work around broken boot loaders. This should 2375 be set to 'N' under normal conditions. 2376 2377config MODIFY_LDT_SYSCALL 2378 bool "Enable the LDT (local descriptor table)" if EXPERT 2379 default y 2380 help 2381 Linux can allow user programs to install a per-process x86 2382 Local Descriptor Table (LDT) using the modify_ldt(2) system 2383 call. This is required to run 16-bit or segmented code such as 2384 DOSEMU or some Wine programs. It is also used by some very old 2385 threading libraries. 2386 2387 Enabling this feature adds a small amount of overhead to 2388 context switches and increases the low-level kernel attack 2389 surface. Disabling it removes the modify_ldt(2) system call. 2390 2391 Saying 'N' here may make sense for embedded or server kernels. 2392 2393source "kernel/livepatch/Kconfig" 2394 2395endmenu 2396 2397config ARCH_HAS_ADD_PAGES 2398 def_bool y 2399 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2400 2401config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2402 def_bool y 2403 2404config USE_PERCPU_NUMA_NODE_ID 2405 def_bool y 2406 depends on NUMA 2407 2408menu "Power management and ACPI options" 2409 2410config ARCH_HIBERNATION_HEADER 2411 def_bool y 2412 depends on HIBERNATION 2413 2414source "kernel/power/Kconfig" 2415 2416source "drivers/acpi/Kconfig" 2417 2418config X86_APM_BOOT 2419 def_bool y 2420 depends on APM 2421 2422menuconfig APM 2423 tristate "APM (Advanced Power Management) BIOS support" 2424 depends on X86_32 && PM_SLEEP 2425 help 2426 APM is a BIOS specification for saving power using several different 2427 techniques. This is mostly useful for battery powered laptops with 2428 APM compliant BIOSes. If you say Y here, the system time will be 2429 reset after a RESUME operation, the /proc/apm device will provide 2430 battery status information, and user-space programs will receive 2431 notification of APM "events" (e.g. battery status change). 2432 2433 If you select "Y" here, you can disable actual use of the APM 2434 BIOS by passing the "apm=off" option to the kernel at boot time. 2435 2436 Note that the APM support is almost completely disabled for 2437 machines with more than one CPU. 2438 2439 In order to use APM, you will need supporting software. For location 2440 and more information, read <file:Documentation/power/apm-acpi.rst> 2441 and the Battery Powered Linux mini-HOWTO, available from 2442 <http://www.tldp.org/docs.html#howto>. 2443 2444 This driver does not spin down disk drives (see the hdparm(8) 2445 manpage ("man 8 hdparm") for that), and it doesn't turn off 2446 VESA-compliant "green" monitors. 2447 2448 This driver does not support the TI 4000M TravelMate and the ACER 2449 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2450 desktop machines also don't have compliant BIOSes, and this driver 2451 may cause those machines to panic during the boot phase. 2452 2453 Generally, if you don't have a battery in your machine, there isn't 2454 much point in using this driver and you should say N. If you get 2455 random kernel OOPSes or reboots that don't seem to be related to 2456 anything, try disabling/enabling this option (or disabling/enabling 2457 APM in your BIOS). 2458 2459 Some other things you should try when experiencing seemingly random, 2460 "weird" problems: 2461 2462 1) make sure that you have enough swap space and that it is 2463 enabled. 2464 2) pass the "no-hlt" option to the kernel 2465 3) switch on floating point emulation in the kernel and pass 2466 the "no387" option to the kernel 2467 4) pass the "floppy=nodma" option to the kernel 2468 5) pass the "mem=4M" option to the kernel (thereby disabling 2469 all but the first 4 MB of RAM) 2470 6) make sure that the CPU is not over clocked. 2471 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2472 8) disable the cache from your BIOS settings 2473 9) install a fan for the video card or exchange video RAM 2474 10) install a better fan for the CPU 2475 11) exchange RAM chips 2476 12) exchange the motherboard. 2477 2478 To compile this driver as a module, choose M here: the 2479 module will be called apm. 2480 2481if APM 2482 2483config APM_IGNORE_USER_SUSPEND 2484 bool "Ignore USER SUSPEND" 2485 help 2486 This option will ignore USER SUSPEND requests. On machines with a 2487 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2488 series notebooks, it is necessary to say Y because of a BIOS bug. 2489 2490config APM_DO_ENABLE 2491 bool "Enable PM at boot time" 2492 help 2493 Enable APM features at boot time. From page 36 of the APM BIOS 2494 specification: "When disabled, the APM BIOS does not automatically 2495 power manage devices, enter the Standby State, enter the Suspend 2496 State, or take power saving steps in response to CPU Idle calls." 2497 This driver will make CPU Idle calls when Linux is idle (unless this 2498 feature is turned off -- see "Do CPU IDLE calls", below). This 2499 should always save battery power, but more complicated APM features 2500 will be dependent on your BIOS implementation. You may need to turn 2501 this option off if your computer hangs at boot time when using APM 2502 support, or if it beeps continuously instead of suspending. Turn 2503 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2504 T400CDT. This is off by default since most machines do fine without 2505 this feature. 2506 2507config APM_CPU_IDLE 2508 depends on CPU_IDLE 2509 bool "Make CPU Idle calls when idle" 2510 help 2511 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2512 On some machines, this can activate improved power savings, such as 2513 a slowed CPU clock rate, when the machine is idle. These idle calls 2514 are made after the idle loop has run for some length of time (e.g., 2515 333 mS). On some machines, this will cause a hang at boot time or 2516 whenever the CPU becomes idle. (On machines with more than one CPU, 2517 this option does nothing.) 2518 2519config APM_DISPLAY_BLANK 2520 bool "Enable console blanking using APM" 2521 help 2522 Enable console blanking using the APM. Some laptops can use this to 2523 turn off the LCD backlight when the screen blanker of the Linux 2524 virtual console blanks the screen. Note that this is only used by 2525 the virtual console screen blanker, and won't turn off the backlight 2526 when using the X Window system. This also doesn't have anything to 2527 do with your VESA-compliant power-saving monitor. Further, this 2528 option doesn't work for all laptops -- it might not turn off your 2529 backlight at all, or it might print a lot of errors to the console, 2530 especially if you are using gpm. 2531 2532config APM_ALLOW_INTS 2533 bool "Allow interrupts during APM BIOS calls" 2534 help 2535 Normally we disable external interrupts while we are making calls to 2536 the APM BIOS as a measure to lessen the effects of a badly behaving 2537 BIOS implementation. The BIOS should reenable interrupts if it 2538 needs to. Unfortunately, some BIOSes do not -- especially those in 2539 many of the newer IBM Thinkpads. If you experience hangs when you 2540 suspend, try setting this to Y. Otherwise, say N. 2541 2542endif # APM 2543 2544source "drivers/cpufreq/Kconfig" 2545 2546source "drivers/cpuidle/Kconfig" 2547 2548source "drivers/idle/Kconfig" 2549 2550endmenu 2551 2552 2553menu "Bus options (PCI etc.)" 2554 2555choice 2556 prompt "PCI access mode" 2557 depends on X86_32 && PCI 2558 default PCI_GOANY 2559 help 2560 On PCI systems, the BIOS can be used to detect the PCI devices and 2561 determine their configuration. However, some old PCI motherboards 2562 have BIOS bugs and may crash if this is done. Also, some embedded 2563 PCI-based systems don't have any BIOS at all. Linux can also try to 2564 detect the PCI hardware directly without using the BIOS. 2565 2566 With this option, you can specify how Linux should detect the 2567 PCI devices. If you choose "BIOS", the BIOS will be used, 2568 if you choose "Direct", the BIOS won't be used, and if you 2569 choose "MMConfig", then PCI Express MMCONFIG will be used. 2570 If you choose "Any", the kernel will try MMCONFIG, then the 2571 direct access method and falls back to the BIOS if that doesn't 2572 work. If unsure, go with the default, which is "Any". 2573 2574config PCI_GOBIOS 2575 bool "BIOS" 2576 2577config PCI_GOMMCONFIG 2578 bool "MMConfig" 2579 2580config PCI_GODIRECT 2581 bool "Direct" 2582 2583config PCI_GOOLPC 2584 bool "OLPC XO-1" 2585 depends on OLPC 2586 2587config PCI_GOANY 2588 bool "Any" 2589 2590endchoice 2591 2592config PCI_BIOS 2593 def_bool y 2594 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2595 2596# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2597config PCI_DIRECT 2598 def_bool y 2599 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2600 2601config PCI_MMCONFIG 2602 bool "Support mmconfig PCI config space access" if X86_64 2603 default y 2604 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2605 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2606 2607config PCI_OLPC 2608 def_bool y 2609 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2610 2611config PCI_XEN 2612 def_bool y 2613 depends on PCI && XEN 2614 2615config MMCONF_FAM10H 2616 def_bool y 2617 depends on X86_64 && PCI_MMCONFIG && ACPI 2618 2619config PCI_CNB20LE_QUIRK 2620 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2621 depends on PCI 2622 help 2623 Read the PCI windows out of the CNB20LE host bridge. This allows 2624 PCI hotplug to work on systems with the CNB20LE chipset which do 2625 not have ACPI. 2626 2627 There's no public spec for this chipset, and this functionality 2628 is known to be incomplete. 2629 2630 You should say N unless you know you need this. 2631 2632config ISA_BUS 2633 bool "ISA bus support on modern systems" if EXPERT 2634 help 2635 Expose ISA bus device drivers and options available for selection and 2636 configuration. Enable this option if your target machine has an ISA 2637 bus. ISA is an older system, displaced by PCI and newer bus 2638 architectures -- if your target machine is modern, it probably does 2639 not have an ISA bus. 2640 2641 If unsure, say N. 2642 2643# x86_64 have no ISA slots, but can have ISA-style DMA. 2644config ISA_DMA_API 2645 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2646 default y 2647 help 2648 Enables ISA-style DMA support for devices requiring such controllers. 2649 If unsure, say Y. 2650 2651if X86_32 2652 2653config ISA 2654 bool "ISA support" 2655 help 2656 Find out whether you have ISA slots on your motherboard. ISA is the 2657 name of a bus system, i.e. the way the CPU talks to the other stuff 2658 inside your box. Other bus systems are PCI, EISA, MicroChannel 2659 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2660 newer boards don't support it. If you have ISA, say Y, otherwise N. 2661 2662config SCx200 2663 tristate "NatSemi SCx200 support" 2664 help 2665 This provides basic support for National Semiconductor's 2666 (now AMD's) Geode processors. The driver probes for the 2667 PCI-IDs of several on-chip devices, so its a good dependency 2668 for other scx200_* drivers. 2669 2670 If compiled as a module, the driver is named scx200. 2671 2672config SCx200HR_TIMER 2673 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2674 depends on SCx200 2675 default y 2676 help 2677 This driver provides a clocksource built upon the on-chip 2678 27MHz high-resolution timer. Its also a workaround for 2679 NSC Geode SC-1100's buggy TSC, which loses time when the 2680 processor goes idle (as is done by the scheduler). The 2681 other workaround is idle=poll boot option. 2682 2683config OLPC 2684 bool "One Laptop Per Child support" 2685 depends on !X86_PAE 2686 select GPIOLIB 2687 select OF 2688 select OF_PROMTREE 2689 select IRQ_DOMAIN 2690 select OLPC_EC 2691 help 2692 Add support for detecting the unique features of the OLPC 2693 XO hardware. 2694 2695config OLPC_XO1_PM 2696 bool "OLPC XO-1 Power Management" 2697 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2698 help 2699 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2700 2701config OLPC_XO1_RTC 2702 bool "OLPC XO-1 Real Time Clock" 2703 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2704 help 2705 Add support for the XO-1 real time clock, which can be used as a 2706 programmable wakeup source. 2707 2708config OLPC_XO1_SCI 2709 bool "OLPC XO-1 SCI extras" 2710 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2711 depends on INPUT=y 2712 select POWER_SUPPLY 2713 help 2714 Add support for SCI-based features of the OLPC XO-1 laptop: 2715 - EC-driven system wakeups 2716 - Power button 2717 - Ebook switch 2718 - Lid switch 2719 - AC adapter status updates 2720 - Battery status updates 2721 2722config OLPC_XO15_SCI 2723 bool "OLPC XO-1.5 SCI extras" 2724 depends on OLPC && ACPI 2725 select POWER_SUPPLY 2726 help 2727 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2728 - EC-driven system wakeups 2729 - AC adapter status updates 2730 - Battery status updates 2731 2732config ALIX 2733 bool "PCEngines ALIX System Support (LED setup)" 2734 select GPIOLIB 2735 help 2736 This option enables system support for the PCEngines ALIX. 2737 At present this just sets up LEDs for GPIO control on 2738 ALIX2/3/6 boards. However, other system specific setup should 2739 get added here. 2740 2741 Note: You must still enable the drivers for GPIO and LED support 2742 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2743 2744 Note: You have to set alix.force=1 for boards with Award BIOS. 2745 2746config NET5501 2747 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2748 select GPIOLIB 2749 help 2750 This option enables system support for the Soekris Engineering net5501. 2751 2752config GEOS 2753 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2754 select GPIOLIB 2755 depends on DMI 2756 help 2757 This option enables system support for the Traverse Technologies GEOS. 2758 2759config TS5500 2760 bool "Technologic Systems TS-5500 platform support" 2761 depends on MELAN 2762 select CHECK_SIGNATURE 2763 select NEW_LEDS 2764 select LEDS_CLASS 2765 help 2766 This option enables system support for the Technologic Systems TS-5500. 2767 2768endif # X86_32 2769 2770config AMD_NB 2771 def_bool y 2772 depends on CPU_SUP_AMD && PCI 2773 2774endmenu 2775 2776 2777menu "Binary Emulations" 2778 2779config IA32_EMULATION 2780 bool "IA32 Emulation" 2781 depends on X86_64 2782 select ARCH_WANT_OLD_COMPAT_IPC 2783 select BINFMT_ELF 2784 select COMPAT_OLD_SIGACTION 2785 help 2786 Include code to run legacy 32-bit programs under a 2787 64-bit kernel. You should likely turn this on, unless you're 2788 100% sure that you don't have any 32-bit programs left. 2789 2790config IA32_AOUT 2791 tristate "IA32 a.out support" 2792 depends on IA32_EMULATION 2793 depends on BROKEN 2794 help 2795 Support old a.out binaries in the 32bit emulation. 2796 2797config X86_X32 2798 bool "x32 ABI for 64-bit mode" 2799 depends on X86_64 2800 help 2801 Include code to run binaries for the x32 native 32-bit ABI 2802 for 64-bit processors. An x32 process gets access to the 2803 full 64-bit register file and wide data path while leaving 2804 pointers at 32 bits for smaller memory footprint. 2805 2806 You will need a recent binutils (2.22 or later) with 2807 elf32_x86_64 support enabled to compile a kernel with this 2808 option set. 2809 2810config COMPAT_32 2811 def_bool y 2812 depends on IA32_EMULATION || X86_32 2813 select HAVE_UID16 2814 select OLD_SIGSUSPEND3 2815 2816config COMPAT 2817 def_bool y 2818 depends on IA32_EMULATION || X86_X32 2819 2820if COMPAT 2821config COMPAT_FOR_U64_ALIGNMENT 2822 def_bool y 2823 2824config SYSVIPC_COMPAT 2825 def_bool y 2826 depends on SYSVIPC 2827endif 2828 2829endmenu 2830 2831 2832config HAVE_ATOMIC_IOMAP 2833 def_bool y 2834 depends on X86_32 2835 2836source "drivers/firmware/Kconfig" 2837 2838source "arch/x86/kvm/Kconfig" 2839 2840source "arch/x86/Kconfig.assembler" 2841