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_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION 65 select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 || (X86_32 && HIGHMEM) 66 select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG 67 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 68 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 69 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 70 select ARCH_HAS_CACHE_LINE_SIZE 71 select ARCH_HAS_DEBUG_VIRTUAL 72 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 73 select ARCH_HAS_DEVMEM_IS_ALLOWED 74 select ARCH_HAS_EARLY_DEBUG if KGDB 75 select ARCH_HAS_ELF_RANDOMIZE 76 select ARCH_HAS_FAST_MULTIPLIER 77 select ARCH_HAS_FILTER_PGPROT 78 select ARCH_HAS_FORTIFY_SOURCE 79 select ARCH_HAS_GCOV_PROFILE_ALL 80 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 81 select ARCH_HAS_MEM_ENCRYPT 82 select ARCH_HAS_MEMBARRIER_SYNC_CORE 83 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 84 select ARCH_HAS_PMEM_API if X86_64 85 select ARCH_HAS_PTE_DEVMAP if X86_64 86 select ARCH_HAS_PTE_SPECIAL 87 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 88 select ARCH_HAS_COPY_MC if X86_64 89 select ARCH_HAS_SET_MEMORY 90 select ARCH_HAS_SET_DIRECT_MAP 91 select ARCH_HAS_STRICT_KERNEL_RWX 92 select ARCH_HAS_STRICT_MODULE_RWX 93 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 94 select ARCH_HAS_SYSCALL_WRAPPER 95 select ARCH_HAS_UBSAN_SANITIZE_ALL 96 select ARCH_HAS_DEBUG_WX 97 select ARCH_HAS_ZONE_DMA_SET if EXPERT 98 select ARCH_HAVE_NMI_SAFE_CMPXCHG 99 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 100 select ARCH_MIGHT_HAVE_PC_PARPORT 101 select ARCH_MIGHT_HAVE_PC_SERIO 102 select ARCH_STACKWALK 103 select ARCH_SUPPORTS_ACPI 104 select ARCH_SUPPORTS_ATOMIC_RMW 105 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 106 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 107 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 108 select ARCH_SUPPORTS_LTO_CLANG 109 select ARCH_SUPPORTS_LTO_CLANG_THIN 110 select ARCH_USE_BUILTIN_BSWAP 111 select ARCH_USE_MEMTEST 112 select ARCH_USE_QUEUED_RWLOCKS 113 select ARCH_USE_QUEUED_SPINLOCKS 114 select ARCH_USE_SYM_ANNOTATIONS 115 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 116 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 117 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 118 select ARCH_WANTS_NO_INSTR 119 select ARCH_WANT_HUGE_PMD_SHARE 120 select ARCH_WANT_LD_ORPHAN_WARN 121 select ARCH_WANTS_THP_SWAP if X86_64 122 select ARCH_HAS_PARANOID_L1D_FLUSH 123 select BUILDTIME_TABLE_SORT 124 select CLKEVT_I8253 125 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 126 select CLOCKSOURCE_WATCHDOG 127 select DCACHE_WORD_ACCESS 128 select EDAC_ATOMIC_SCRUB 129 select EDAC_SUPPORT 130 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 131 select GENERIC_CLOCKEVENTS_MIN_ADJUST 132 select GENERIC_CMOS_UPDATE 133 select GENERIC_CPU_AUTOPROBE 134 select GENERIC_CPU_VULNERABILITIES 135 select GENERIC_EARLY_IOREMAP 136 select GENERIC_ENTRY 137 select GENERIC_FIND_FIRST_BIT 138 select GENERIC_IOMAP 139 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 140 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 141 select GENERIC_IRQ_MIGRATION if SMP 142 select GENERIC_IRQ_PROBE 143 select GENERIC_IRQ_RESERVATION_MODE 144 select GENERIC_IRQ_SHOW 145 select GENERIC_PENDING_IRQ if SMP 146 select GENERIC_PTDUMP 147 select GENERIC_SMP_IDLE_THREAD 148 select GENERIC_TIME_VSYSCALL 149 select GENERIC_GETTIMEOFDAY 150 select GENERIC_VDSO_TIME_NS 151 select GUP_GET_PTE_LOW_HIGH if X86_PAE 152 select HARDIRQS_SW_RESEND 153 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 154 select HAVE_ACPI_APEI if ACPI 155 select HAVE_ACPI_APEI_NMI if ACPI 156 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 157 select HAVE_ARCH_AUDITSYSCALL 158 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 159 select HAVE_ARCH_JUMP_LABEL 160 select HAVE_ARCH_JUMP_LABEL_RELATIVE 161 select HAVE_ARCH_KASAN if X86_64 162 select HAVE_ARCH_KASAN_VMALLOC if X86_64 163 select HAVE_ARCH_KFENCE 164 select HAVE_ARCH_KGDB 165 select HAVE_ARCH_MMAP_RND_BITS if MMU 166 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 167 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 168 select HAVE_ARCH_PREL32_RELOCATIONS 169 select HAVE_ARCH_SECCOMP_FILTER 170 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 171 select HAVE_ARCH_STACKLEAK 172 select HAVE_ARCH_TRACEHOOK 173 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 174 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 175 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 176 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 177 select HAVE_ARCH_VMAP_STACK if X86_64 178 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 179 select HAVE_ARCH_WITHIN_STACK_FRAMES 180 select HAVE_ASM_MODVERSIONS 181 select HAVE_CMPXCHG_DOUBLE 182 select HAVE_CMPXCHG_LOCAL 183 select HAVE_CONTEXT_TRACKING if X86_64 184 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING 185 select HAVE_C_RECORDMCOUNT 186 select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION 187 select HAVE_DEBUG_KMEMLEAK 188 select HAVE_DMA_CONTIGUOUS 189 select HAVE_DYNAMIC_FTRACE 190 select HAVE_DYNAMIC_FTRACE_WITH_REGS 191 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 192 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 193 select HAVE_EBPF_JIT 194 select HAVE_EFFICIENT_UNALIGNED_ACCESS 195 select HAVE_EISA 196 select HAVE_EXIT_THREAD 197 select HAVE_FAST_GUP 198 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 199 select HAVE_FTRACE_MCOUNT_RECORD 200 select HAVE_FUNCTION_GRAPH_TRACER 201 select HAVE_FUNCTION_TRACER 202 select HAVE_GCC_PLUGINS 203 select HAVE_HW_BREAKPOINT 204 select HAVE_IOREMAP_PROT 205 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 206 select HAVE_IRQ_TIME_ACCOUNTING 207 select HAVE_KERNEL_BZIP2 208 select HAVE_KERNEL_GZIP 209 select HAVE_KERNEL_LZ4 210 select HAVE_KERNEL_LZMA 211 select HAVE_KERNEL_LZO 212 select HAVE_KERNEL_XZ 213 select HAVE_KERNEL_ZSTD 214 select HAVE_KPROBES 215 select HAVE_KPROBES_ON_FTRACE 216 select HAVE_FUNCTION_ERROR_INJECTION 217 select HAVE_KRETPROBES 218 select HAVE_KVM 219 select HAVE_LIVEPATCH if X86_64 220 select HAVE_MIXED_BREAKPOINTS_REGS 221 select HAVE_MOD_ARCH_SPECIFIC 222 select HAVE_MOVE_PMD 223 select HAVE_MOVE_PUD 224 select HAVE_NMI 225 select HAVE_OPTPROBES 226 select HAVE_PCSPKR_PLATFORM 227 select HAVE_PERF_EVENTS 228 select HAVE_PERF_EVENTS_NMI 229 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 230 select HAVE_PCI 231 select HAVE_PERF_REGS 232 select HAVE_PERF_USER_STACK_DUMP 233 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 234 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 235 select HAVE_REGS_AND_STACK_ACCESS_API 236 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 237 select HAVE_FUNCTION_ARG_ACCESS_API 238 select HAVE_SOFTIRQ_ON_OWN_STACK 239 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 240 select HAVE_STACK_VALIDATION if X86_64 241 select HAVE_STATIC_CALL 242 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 243 select HAVE_PREEMPT_DYNAMIC 244 select HAVE_RSEQ 245 select HAVE_SYSCALL_TRACEPOINTS 246 select HAVE_UNSTABLE_SCHED_CLOCK 247 select HAVE_USER_RETURN_NOTIFIER 248 select HAVE_GENERIC_VDSO 249 select HOTPLUG_SMT if SMP 250 select IRQ_FORCED_THREADING 251 select NEED_SG_DMA_LENGTH 252 select PCI_DOMAINS if PCI 253 select PCI_LOCKLESS_CONFIG if PCI 254 select PERF_EVENTS 255 select RTC_LIB 256 select RTC_MC146818_LIB 257 select SPARSE_IRQ 258 select SRCU 259 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 260 select SYSCTL_EXCEPTION_TRACE 261 select THREAD_INFO_IN_TASK 262 select TRACE_IRQFLAGS_SUPPORT 263 select USER_STACKTRACE_SUPPORT 264 select VIRT_TO_BUS 265 select HAVE_ARCH_KCSAN if X86_64 266 select X86_FEATURE_NAMES if PROC_FS 267 select PROC_PID_ARCH_STATUS if PROC_FS 268 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 269 270config INSTRUCTION_DECODER 271 def_bool y 272 depends on KPROBES || PERF_EVENTS || UPROBES 273 274config OUTPUT_FORMAT 275 string 276 default "elf32-i386" if X86_32 277 default "elf64-x86-64" if X86_64 278 279config LOCKDEP_SUPPORT 280 def_bool y 281 282config STACKTRACE_SUPPORT 283 def_bool y 284 285config MMU 286 def_bool y 287 288config ARCH_MMAP_RND_BITS_MIN 289 default 28 if 64BIT 290 default 8 291 292config ARCH_MMAP_RND_BITS_MAX 293 default 32 if 64BIT 294 default 16 295 296config ARCH_MMAP_RND_COMPAT_BITS_MIN 297 default 8 298 299config ARCH_MMAP_RND_COMPAT_BITS_MAX 300 default 16 301 302config SBUS 303 bool 304 305config GENERIC_ISA_DMA 306 def_bool y 307 depends on ISA_DMA_API 308 309config GENERIC_BUG 310 def_bool y 311 depends on BUG 312 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 313 314config GENERIC_BUG_RELATIVE_POINTERS 315 bool 316 317config ARCH_MAY_HAVE_PC_FDC 318 def_bool y 319 depends on ISA_DMA_API 320 321config GENERIC_CALIBRATE_DELAY 322 def_bool y 323 324config ARCH_HAS_CPU_RELAX 325 def_bool y 326 327config ARCH_HAS_FILTER_PGPROT 328 def_bool y 329 330config HAVE_SETUP_PER_CPU_AREA 331 def_bool y 332 333config NEED_PER_CPU_EMBED_FIRST_CHUNK 334 def_bool y 335 336config NEED_PER_CPU_PAGE_FIRST_CHUNK 337 def_bool y 338 339config ARCH_HIBERNATION_POSSIBLE 340 def_bool y 341 342config ARCH_NR_GPIO 343 int 344 default 1024 if X86_64 345 default 512 346 347config ARCH_SUSPEND_POSSIBLE 348 def_bool y 349 350config ARCH_WANT_GENERAL_HUGETLB 351 def_bool y 352 353config AUDIT_ARCH 354 def_bool y if X86_64 355 356config KASAN_SHADOW_OFFSET 357 hex 358 depends on KASAN 359 default 0xdffffc0000000000 360 361config HAVE_INTEL_TXT 362 def_bool y 363 depends on INTEL_IOMMU && ACPI 364 365config X86_32_SMP 366 def_bool y 367 depends on X86_32 && SMP 368 369config X86_64_SMP 370 def_bool y 371 depends on X86_64 && SMP 372 373config ARCH_SUPPORTS_UPROBES 374 def_bool y 375 376config FIX_EARLYCON_MEM 377 def_bool y 378 379config DYNAMIC_PHYSICAL_MASK 380 bool 381 382config PGTABLE_LEVELS 383 int 384 default 5 if X86_5LEVEL 385 default 4 if X86_64 386 default 3 if X86_PAE 387 default 2 388 389config CC_HAS_SANE_STACKPROTECTOR 390 bool 391 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 392 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 393 help 394 We have to make sure stack protector is unconditionally disabled if 395 the compiler produces broken code or if it does not let us control 396 the segment on 32-bit kernels. 397 398menu "Processor type and features" 399 400config SMP 401 bool "Symmetric multi-processing support" 402 help 403 This enables support for systems with more than one CPU. If you have 404 a system with only one CPU, say N. If you have a system with more 405 than one CPU, say Y. 406 407 If you say N here, the kernel will run on uni- and multiprocessor 408 machines, but will use only one CPU of a multiprocessor machine. If 409 you say Y here, the kernel will run on many, but not all, 410 uniprocessor machines. On a uniprocessor machine, the kernel 411 will run faster if you say N here. 412 413 Note that if you say Y here and choose architecture "586" or 414 "Pentium" under "Processor family", the kernel will not work on 486 415 architectures. Similarly, multiprocessor kernels for the "PPro" 416 architecture may not work on all Pentium based boards. 417 418 People using multiprocessor machines who say Y here should also say 419 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 420 Management" code will be disabled if you say Y here. 421 422 See also <file:Documentation/x86/i386/IO-APIC.rst>, 423 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 424 <http://www.tldp.org/docs.html#howto>. 425 426 If you don't know what to do here, say N. 427 428config X86_FEATURE_NAMES 429 bool "Processor feature human-readable names" if EMBEDDED 430 default y 431 help 432 This option compiles in a table of x86 feature bits and corresponding 433 names. This is required to support /proc/cpuinfo and a few kernel 434 messages. You can disable this to save space, at the expense of 435 making those few kernel messages show numeric feature bits instead. 436 437 If in doubt, say Y. 438 439config X86_X2APIC 440 bool "Support x2apic" 441 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 442 help 443 This enables x2apic support on CPUs that have this feature. 444 445 This allows 32-bit apic IDs (so it can support very large systems), 446 and accesses the local apic via MSRs not via mmio. 447 448 If you don't know what to do here, say N. 449 450config X86_MPPARSE 451 bool "Enable MPS table" if ACPI 452 default y 453 depends on X86_LOCAL_APIC 454 help 455 For old smp systems that do not have proper acpi support. Newer systems 456 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 457 458config GOLDFISH 459 def_bool y 460 depends on X86_GOLDFISH 461 462config RETPOLINE 463 bool "Avoid speculative indirect branches in kernel" 464 default y 465 help 466 Compile kernel with the retpoline compiler options to guard against 467 kernel-to-user data leaks by avoiding speculative indirect 468 branches. Requires a compiler with -mindirect-branch=thunk-extern 469 support for full protection. The kernel may run slower. 470 471config X86_CPU_RESCTRL 472 bool "x86 CPU resource control support" 473 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 474 select KERNFS 475 select PROC_CPU_RESCTRL if PROC_FS 476 help 477 Enable x86 CPU resource control support. 478 479 Provide support for the allocation and monitoring of system resources 480 usage by the CPU. 481 482 Intel calls this Intel Resource Director Technology 483 (Intel(R) RDT). More information about RDT can be found in the 484 Intel x86 Architecture Software Developer Manual. 485 486 AMD calls this AMD Platform Quality of Service (AMD QoS). 487 More information about AMD QoS can be found in the AMD64 Technology 488 Platform Quality of Service Extensions manual. 489 490 Say N if unsure. 491 492if X86_32 493config X86_BIGSMP 494 bool "Support for big SMP systems with more than 8 CPUs" 495 depends on SMP 496 help 497 This option is needed for the systems that have more than 8 CPUs. 498 499config X86_EXTENDED_PLATFORM 500 bool "Support for extended (non-PC) x86 platforms" 501 default y 502 help 503 If you disable this option then the kernel will only support 504 standard PC platforms. (which covers the vast majority of 505 systems out there.) 506 507 If you enable this option then you'll be able to select support 508 for the following (non-PC) 32 bit x86 platforms: 509 Goldfish (Android emulator) 510 AMD Elan 511 RDC R-321x SoC 512 SGI 320/540 (Visual Workstation) 513 STA2X11-based (e.g. Northville) 514 Moorestown MID devices 515 516 If you have one of these systems, or if you want to build a 517 generic distribution kernel, say Y here - otherwise say N. 518endif 519 520if X86_64 521config X86_EXTENDED_PLATFORM 522 bool "Support for extended (non-PC) x86 platforms" 523 default y 524 help 525 If you disable this option then the kernel will only support 526 standard PC platforms. (which covers the vast majority of 527 systems out there.) 528 529 If you enable this option then you'll be able to select support 530 for the following (non-PC) 64 bit x86 platforms: 531 Numascale NumaChip 532 ScaleMP vSMP 533 SGI Ultraviolet 534 535 If you have one of these systems, or if you want to build a 536 generic distribution kernel, say Y here - otherwise say N. 537endif 538# This is an alphabetically sorted list of 64 bit extended platforms 539# Please maintain the alphabetic order if and when there are additions 540config X86_NUMACHIP 541 bool "Numascale NumaChip" 542 depends on X86_64 543 depends on X86_EXTENDED_PLATFORM 544 depends on NUMA 545 depends on SMP 546 depends on X86_X2APIC 547 depends on PCI_MMCONFIG 548 help 549 Adds support for Numascale NumaChip large-SMP systems. Needed to 550 enable more than ~168 cores. 551 If you don't have one of these, you should say N here. 552 553config X86_VSMP 554 bool "ScaleMP vSMP" 555 select HYPERVISOR_GUEST 556 select PARAVIRT 557 depends on X86_64 && PCI 558 depends on X86_EXTENDED_PLATFORM 559 depends on SMP 560 help 561 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 562 supposed to run on these EM64T-based machines. Only choose this option 563 if you have one of these machines. 564 565config X86_UV 566 bool "SGI Ultraviolet" 567 depends on X86_64 568 depends on X86_EXTENDED_PLATFORM 569 depends on NUMA 570 depends on EFI 571 depends on KEXEC_CORE 572 depends on X86_X2APIC 573 depends on PCI 574 help 575 This option is needed in order to support SGI Ultraviolet systems. 576 If you don't have one of these, you should say N here. 577 578# Following is an alphabetically sorted list of 32 bit extended platforms 579# Please maintain the alphabetic order if and when there are additions 580 581config X86_GOLDFISH 582 bool "Goldfish (Virtual Platform)" 583 depends on X86_EXTENDED_PLATFORM 584 help 585 Enable support for the Goldfish virtual platform used primarily 586 for Android development. Unless you are building for the Android 587 Goldfish emulator say N here. 588 589config X86_INTEL_CE 590 bool "CE4100 TV platform" 591 depends on PCI 592 depends on PCI_GODIRECT 593 depends on X86_IO_APIC 594 depends on X86_32 595 depends on X86_EXTENDED_PLATFORM 596 select X86_REBOOTFIXUPS 597 select OF 598 select OF_EARLY_FLATTREE 599 help 600 Select for the Intel CE media processor (CE4100) SOC. 601 This option compiles in support for the CE4100 SOC for settop 602 boxes and media devices. 603 604config X86_INTEL_MID 605 bool "Intel MID platform support" 606 depends on X86_EXTENDED_PLATFORM 607 depends on X86_PLATFORM_DEVICES 608 depends on PCI 609 depends on X86_64 || (PCI_GOANY && X86_32) 610 depends on X86_IO_APIC 611 select I2C 612 select DW_APB_TIMER 613 select APB_TIMER 614 select INTEL_SCU_PCI 615 select MFD_INTEL_MSIC 616 help 617 Select to build a kernel capable of supporting Intel MID (Mobile 618 Internet Device) platform systems which do not have the PCI legacy 619 interfaces. If you are building for a PC class system say N here. 620 621 Intel MID platforms are based on an Intel processor and chipset which 622 consume less power than most of the x86 derivatives. 623 624config X86_INTEL_QUARK 625 bool "Intel Quark platform support" 626 depends on X86_32 627 depends on X86_EXTENDED_PLATFORM 628 depends on X86_PLATFORM_DEVICES 629 depends on X86_TSC 630 depends on PCI 631 depends on PCI_GOANY 632 depends on X86_IO_APIC 633 select IOSF_MBI 634 select INTEL_IMR 635 select COMMON_CLK 636 help 637 Select to include support for Quark X1000 SoC. 638 Say Y here if you have a Quark based system such as the Arduino 639 compatible Intel Galileo. 640 641config X86_INTEL_LPSS 642 bool "Intel Low Power Subsystem Support" 643 depends on X86 && ACPI && PCI 644 select COMMON_CLK 645 select PINCTRL 646 select IOSF_MBI 647 help 648 Select to build support for Intel Low Power Subsystem such as 649 found on Intel Lynxpoint PCH. Selecting this option enables 650 things like clock tree (common clock framework) and pincontrol 651 which are needed by the LPSS peripheral drivers. 652 653config X86_AMD_PLATFORM_DEVICE 654 bool "AMD ACPI2Platform devices support" 655 depends on ACPI 656 select COMMON_CLK 657 select PINCTRL 658 help 659 Select to interpret AMD specific ACPI device to platform device 660 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 661 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 662 implemented under PINCTRL subsystem. 663 664config IOSF_MBI 665 tristate "Intel SoC IOSF Sideband support for SoC platforms" 666 depends on PCI 667 help 668 This option enables sideband register access support for Intel SoC 669 platforms. On these platforms the IOSF sideband is used in lieu of 670 MSR's for some register accesses, mostly but not limited to thermal 671 and power. Drivers may query the availability of this device to 672 determine if they need the sideband in order to work on these 673 platforms. The sideband is available on the following SoC products. 674 This list is not meant to be exclusive. 675 - BayTrail 676 - Braswell 677 - Quark 678 679 You should say Y if you are running a kernel on one of these SoC's. 680 681config IOSF_MBI_DEBUG 682 bool "Enable IOSF sideband access through debugfs" 683 depends on IOSF_MBI && DEBUG_FS 684 help 685 Select this option to expose the IOSF sideband access registers (MCR, 686 MDR, MCRX) through debugfs to write and read register information from 687 different units on the SoC. This is most useful for obtaining device 688 state information for debug and analysis. As this is a general access 689 mechanism, users of this option would have specific knowledge of the 690 device they want to access. 691 692 If you don't require the option or are in doubt, say N. 693 694config X86_RDC321X 695 bool "RDC R-321x SoC" 696 depends on X86_32 697 depends on X86_EXTENDED_PLATFORM 698 select M486 699 select X86_REBOOTFIXUPS 700 help 701 This option is needed for RDC R-321x system-on-chip, also known 702 as R-8610-(G). 703 If you don't have one of these chips, you should say N here. 704 705config X86_32_NON_STANDARD 706 bool "Support non-standard 32-bit SMP architectures" 707 depends on X86_32 && SMP 708 depends on X86_EXTENDED_PLATFORM 709 help 710 This option compiles in the bigsmp and STA2X11 default 711 subarchitectures. It is intended for a generic binary 712 kernel. If you select them all, kernel will probe it one by 713 one and will fallback to default. 714 715# Alphabetically sorted list of Non standard 32 bit platforms 716 717config X86_SUPPORTS_MEMORY_FAILURE 718 def_bool y 719 # MCE code calls memory_failure(): 720 depends on X86_MCE 721 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 722 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 723 depends on X86_64 || !SPARSEMEM 724 select ARCH_SUPPORTS_MEMORY_FAILURE 725 726config STA2X11 727 bool "STA2X11 Companion Chip Support" 728 depends on X86_32_NON_STANDARD && PCI 729 select SWIOTLB 730 select MFD_STA2X11 731 select GPIOLIB 732 help 733 This adds support for boards based on the STA2X11 IO-Hub, 734 a.k.a. "ConneXt". The chip is used in place of the standard 735 PC chipset, so all "standard" peripherals are missing. If this 736 option is selected the kernel will still be able to boot on 737 standard PC machines. 738 739config X86_32_IRIS 740 tristate "Eurobraille/Iris poweroff module" 741 depends on X86_32 742 help 743 The Iris machines from EuroBraille do not have APM or ACPI support 744 to shut themselves down properly. A special I/O sequence is 745 needed to do so, which is what this module does at 746 kernel shutdown. 747 748 This is only for Iris machines from EuroBraille. 749 750 If unused, say N. 751 752config SCHED_OMIT_FRAME_POINTER 753 def_bool y 754 prompt "Single-depth WCHAN output" 755 depends on X86 756 help 757 Calculate simpler /proc/<PID>/wchan values. If this option 758 is disabled then wchan values will recurse back to the 759 caller function. This provides more accurate wchan values, 760 at the expense of slightly more scheduling overhead. 761 762 If in doubt, say "Y". 763 764menuconfig HYPERVISOR_GUEST 765 bool "Linux guest support" 766 help 767 Say Y here to enable options for running Linux under various hyper- 768 visors. This option enables basic hypervisor detection and platform 769 setup. 770 771 If you say N, all options in this submenu will be skipped and 772 disabled, and Linux guest support won't be built in. 773 774if HYPERVISOR_GUEST 775 776config PARAVIRT 777 bool "Enable paravirtualization code" 778 depends on HAVE_STATIC_CALL 779 help 780 This changes the kernel so it can modify itself when it is run 781 under a hypervisor, potentially improving performance significantly 782 over full virtualization. However, when run without a hypervisor 783 the kernel is theoretically slower and slightly larger. 784 785config PARAVIRT_XXL 786 bool 787 788config PARAVIRT_DEBUG 789 bool "paravirt-ops debugging" 790 depends on PARAVIRT && DEBUG_KERNEL 791 help 792 Enable to debug paravirt_ops internals. Specifically, BUG if 793 a paravirt_op is missing when it is called. 794 795config PARAVIRT_SPINLOCKS 796 bool "Paravirtualization layer for spinlocks" 797 depends on PARAVIRT && SMP 798 help 799 Paravirtualized spinlocks allow a pvops backend to replace the 800 spinlock implementation with something virtualization-friendly 801 (for example, block the virtual CPU rather than spinning). 802 803 It has a minimal impact on native kernels and gives a nice performance 804 benefit on paravirtualized KVM / Xen kernels. 805 806 If you are unsure how to answer this question, answer Y. 807 808config X86_HV_CALLBACK_VECTOR 809 def_bool n 810 811source "arch/x86/xen/Kconfig" 812 813config KVM_GUEST 814 bool "KVM Guest support (including kvmclock)" 815 depends on PARAVIRT 816 select PARAVIRT_CLOCK 817 select ARCH_CPUIDLE_HALTPOLL 818 select X86_HV_CALLBACK_VECTOR 819 default y 820 help 821 This option enables various optimizations for running under the KVM 822 hypervisor. It includes a paravirtualized clock, so that instead 823 of relying on a PIT (or probably other) emulation by the 824 underlying device model, the host provides the guest with 825 timing infrastructure such as time of day, and system time 826 827config ARCH_CPUIDLE_HALTPOLL 828 def_bool n 829 prompt "Disable host haltpoll when loading haltpoll driver" 830 help 831 If virtualized under KVM, disable host haltpoll. 832 833config PVH 834 bool "Support for running PVH guests" 835 help 836 This option enables the PVH entry point for guest virtual machines 837 as specified in the x86/HVM direct boot ABI. 838 839config PARAVIRT_TIME_ACCOUNTING 840 bool "Paravirtual steal time accounting" 841 depends on PARAVIRT 842 help 843 Select this option to enable fine granularity task steal time 844 accounting. Time spent executing other tasks in parallel with 845 the current vCPU is discounted from the vCPU power. To account for 846 that, there can be a small performance impact. 847 848 If in doubt, say N here. 849 850config PARAVIRT_CLOCK 851 bool 852 853config JAILHOUSE_GUEST 854 bool "Jailhouse non-root cell support" 855 depends on X86_64 && PCI 856 select X86_PM_TIMER 857 help 858 This option allows to run Linux as guest in a Jailhouse non-root 859 cell. You can leave this option disabled if you only want to start 860 Jailhouse and run Linux afterwards in the root cell. 861 862config ACRN_GUEST 863 bool "ACRN Guest support" 864 depends on X86_64 865 select X86_HV_CALLBACK_VECTOR 866 help 867 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 868 a flexible, lightweight reference open-source hypervisor, built with 869 real-time and safety-criticality in mind. It is built for embedded 870 IOT with small footprint and real-time features. More details can be 871 found in https://projectacrn.org/. 872 873endif #HYPERVISOR_GUEST 874 875source "arch/x86/Kconfig.cpu" 876 877config HPET_TIMER 878 def_bool X86_64 879 prompt "HPET Timer Support" if X86_32 880 help 881 Use the IA-PC HPET (High Precision Event Timer) to manage 882 time in preference to the PIT and RTC, if a HPET is 883 present. 884 HPET is the next generation timer replacing legacy 8254s. 885 The HPET provides a stable time base on SMP 886 systems, unlike the TSC, but it is more expensive to access, 887 as it is off-chip. The interface used is documented 888 in the HPET spec, revision 1. 889 890 You can safely choose Y here. However, HPET will only be 891 activated if the platform and the BIOS support this feature. 892 Otherwise the 8254 will be used for timing services. 893 894 Choose N to continue using the legacy 8254 timer. 895 896config HPET_EMULATE_RTC 897 def_bool y 898 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 899 900# Mark as expert because too many people got it wrong. 901# The code disables itself when not needed. 902config DMI 903 default y 904 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 905 bool "Enable DMI scanning" if EXPERT 906 help 907 Enabled scanning of DMI to identify machine quirks. Say Y 908 here unless you have verified that your setup is not 909 affected by entries in the DMI blacklist. Required by PNP 910 BIOS code. 911 912config GART_IOMMU 913 bool "Old AMD GART IOMMU support" 914 select DMA_OPS 915 select IOMMU_HELPER 916 select SWIOTLB 917 depends on X86_64 && PCI && AMD_NB 918 help 919 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 920 GART based hardware IOMMUs. 921 922 The GART supports full DMA access for devices with 32-bit access 923 limitations, on systems with more than 3 GB. This is usually needed 924 for USB, sound, many IDE/SATA chipsets and some other devices. 925 926 Newer systems typically have a modern AMD IOMMU, supported via 927 the CONFIG_AMD_IOMMU=y config option. 928 929 In normal configurations this driver is only active when needed: 930 there's more than 3 GB of memory and the system contains a 931 32-bit limited device. 932 933 If unsure, say Y. 934 935config MAXSMP 936 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 937 depends on X86_64 && SMP && DEBUG_KERNEL 938 select CPUMASK_OFFSTACK 939 help 940 Enable maximum number of CPUS and NUMA Nodes for this architecture. 941 If unsure, say N. 942 943# 944# The maximum number of CPUs supported: 945# 946# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 947# and which can be configured interactively in the 948# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 949# 950# The ranges are different on 32-bit and 64-bit kernels, depending on 951# hardware capabilities and scalability features of the kernel. 952# 953# ( If MAXSMP is enabled we just use the highest possible value and disable 954# interactive configuration. ) 955# 956 957config NR_CPUS_RANGE_BEGIN 958 int 959 default NR_CPUS_RANGE_END if MAXSMP 960 default 1 if !SMP 961 default 2 962 963config NR_CPUS_RANGE_END 964 int 965 depends on X86_32 966 default 64 if SMP && X86_BIGSMP 967 default 8 if SMP && !X86_BIGSMP 968 default 1 if !SMP 969 970config NR_CPUS_RANGE_END 971 int 972 depends on X86_64 973 default 8192 if SMP && CPUMASK_OFFSTACK 974 default 512 if SMP && !CPUMASK_OFFSTACK 975 default 1 if !SMP 976 977config NR_CPUS_DEFAULT 978 int 979 depends on X86_32 980 default 32 if X86_BIGSMP 981 default 8 if SMP 982 default 1 if !SMP 983 984config NR_CPUS_DEFAULT 985 int 986 depends on X86_64 987 default 8192 if MAXSMP 988 default 64 if SMP 989 default 1 if !SMP 990 991config NR_CPUS 992 int "Maximum number of CPUs" if SMP && !MAXSMP 993 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 994 default NR_CPUS_DEFAULT 995 help 996 This allows you to specify the maximum number of CPUs which this 997 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 998 supported value is 8192, otherwise the maximum value is 512. The 999 minimum value which makes sense is 2. 1000 1001 This is purely to save memory: each supported CPU adds about 8KB 1002 to the kernel image. 1003 1004config SCHED_SMT 1005 def_bool y if SMP 1006 1007config SCHED_MC 1008 def_bool y 1009 prompt "Multi-core scheduler support" 1010 depends on SMP 1011 help 1012 Multi-core scheduler support improves the CPU scheduler's decision 1013 making when dealing with multi-core CPU chips at a cost of slightly 1014 increased overhead in some places. If unsure say N here. 1015 1016config SCHED_MC_PRIO 1017 bool "CPU core priorities scheduler support" 1018 depends on SCHED_MC && CPU_SUP_INTEL 1019 select X86_INTEL_PSTATE 1020 select CPU_FREQ 1021 default y 1022 help 1023 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1024 core ordering determined at manufacturing time, which allows 1025 certain cores to reach higher turbo frequencies (when running 1026 single threaded workloads) than others. 1027 1028 Enabling this kernel feature teaches the scheduler about 1029 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1030 scheduler's CPU selection logic accordingly, so that higher 1031 overall system performance can be achieved. 1032 1033 This feature will have no effect on CPUs without this feature. 1034 1035 If unsure say Y here. 1036 1037config UP_LATE_INIT 1038 def_bool y 1039 depends on !SMP && X86_LOCAL_APIC 1040 1041config X86_UP_APIC 1042 bool "Local APIC support on uniprocessors" if !PCI_MSI 1043 default PCI_MSI 1044 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1045 help 1046 A local APIC (Advanced Programmable Interrupt Controller) is an 1047 integrated interrupt controller in the CPU. If you have a single-CPU 1048 system which has a processor with a local APIC, you can say Y here to 1049 enable and use it. If you say Y here even though your machine doesn't 1050 have a local APIC, then the kernel will still run with no slowdown at 1051 all. The local APIC supports CPU-generated self-interrupts (timer, 1052 performance counters), and the NMI watchdog which detects hard 1053 lockups. 1054 1055config X86_UP_IOAPIC 1056 bool "IO-APIC support on uniprocessors" 1057 depends on X86_UP_APIC 1058 help 1059 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1060 SMP-capable replacement for PC-style interrupt controllers. Most 1061 SMP systems and many recent uniprocessor systems have one. 1062 1063 If you have a single-CPU system with an IO-APIC, you can say Y here 1064 to use it. If you say Y here even though your machine doesn't have 1065 an IO-APIC, then the kernel will still run with no slowdown at all. 1066 1067config X86_LOCAL_APIC 1068 def_bool y 1069 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1070 select IRQ_DOMAIN_HIERARCHY 1071 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1072 1073config X86_IO_APIC 1074 def_bool y 1075 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1076 1077config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1078 bool "Reroute for broken boot IRQs" 1079 depends on X86_IO_APIC 1080 help 1081 This option enables a workaround that fixes a source of 1082 spurious interrupts. This is recommended when threaded 1083 interrupt handling is used on systems where the generation of 1084 superfluous "boot interrupts" cannot be disabled. 1085 1086 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1087 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1088 kernel does during interrupt handling). On chipsets where this 1089 boot IRQ generation cannot be disabled, this workaround keeps 1090 the original IRQ line masked so that only the equivalent "boot 1091 IRQ" is delivered to the CPUs. The workaround also tells the 1092 kernel to set up the IRQ handler on the boot IRQ line. In this 1093 way only one interrupt is delivered to the kernel. Otherwise 1094 the spurious second interrupt may cause the kernel to bring 1095 down (vital) interrupt lines. 1096 1097 Only affects "broken" chipsets. Interrupt sharing may be 1098 increased on these systems. 1099 1100config X86_MCE 1101 bool "Machine Check / overheating reporting" 1102 select GENERIC_ALLOCATOR 1103 default y 1104 help 1105 Machine Check support allows the processor to notify the 1106 kernel if it detects a problem (e.g. overheating, data corruption). 1107 The action the kernel takes depends on the severity of the problem, 1108 ranging from warning messages to halting the machine. 1109 1110config X86_MCELOG_LEGACY 1111 bool "Support for deprecated /dev/mcelog character device" 1112 depends on X86_MCE 1113 help 1114 Enable support for /dev/mcelog which is needed by the old mcelog 1115 userspace logging daemon. Consider switching to the new generation 1116 rasdaemon solution. 1117 1118config X86_MCE_INTEL 1119 def_bool y 1120 prompt "Intel MCE features" 1121 depends on X86_MCE && X86_LOCAL_APIC 1122 help 1123 Additional support for intel specific MCE features such as 1124 the thermal monitor. 1125 1126config X86_MCE_AMD 1127 def_bool y 1128 prompt "AMD MCE features" 1129 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1130 help 1131 Additional support for AMD specific MCE features such as 1132 the DRAM Error Threshold. 1133 1134config X86_ANCIENT_MCE 1135 bool "Support for old Pentium 5 / WinChip machine checks" 1136 depends on X86_32 && X86_MCE 1137 help 1138 Include support for machine check handling on old Pentium 5 or WinChip 1139 systems. These typically need to be enabled explicitly on the command 1140 line. 1141 1142config X86_MCE_THRESHOLD 1143 depends on X86_MCE_AMD || X86_MCE_INTEL 1144 def_bool y 1145 1146config X86_MCE_INJECT 1147 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1148 tristate "Machine check injector support" 1149 help 1150 Provide support for injecting machine checks for testing purposes. 1151 If you don't know what a machine check is and you don't do kernel 1152 QA it is safe to say n. 1153 1154source "arch/x86/events/Kconfig" 1155 1156config X86_LEGACY_VM86 1157 bool "Legacy VM86 support" 1158 depends on X86_32 1159 help 1160 This option allows user programs to put the CPU into V8086 1161 mode, which is an 80286-era approximation of 16-bit real mode. 1162 1163 Some very old versions of X and/or vbetool require this option 1164 for user mode setting. Similarly, DOSEMU will use it if 1165 available to accelerate real mode DOS programs. However, any 1166 recent version of DOSEMU, X, or vbetool should be fully 1167 functional even without kernel VM86 support, as they will all 1168 fall back to software emulation. Nevertheless, if you are using 1169 a 16-bit DOS program where 16-bit performance matters, vm86 1170 mode might be faster than emulation and you might want to 1171 enable this option. 1172 1173 Note that any app that works on a 64-bit kernel is unlikely to 1174 need this option, as 64-bit kernels don't, and can't, support 1175 V8086 mode. This option is also unrelated to 16-bit protected 1176 mode and is not needed to run most 16-bit programs under Wine. 1177 1178 Enabling this option increases the complexity of the kernel 1179 and slows down exception handling a tiny bit. 1180 1181 If unsure, say N here. 1182 1183config VM86 1184 bool 1185 default X86_LEGACY_VM86 1186 1187config X86_16BIT 1188 bool "Enable support for 16-bit segments" if EXPERT 1189 default y 1190 depends on MODIFY_LDT_SYSCALL 1191 help 1192 This option is required by programs like Wine to run 16-bit 1193 protected mode legacy code on x86 processors. Disabling 1194 this option saves about 300 bytes on i386, or around 6K text 1195 plus 16K runtime memory on x86-64, 1196 1197config X86_ESPFIX32 1198 def_bool y 1199 depends on X86_16BIT && X86_32 1200 1201config X86_ESPFIX64 1202 def_bool y 1203 depends on X86_16BIT && X86_64 1204 1205config X86_VSYSCALL_EMULATION 1206 bool "Enable vsyscall emulation" if EXPERT 1207 default y 1208 depends on X86_64 1209 help 1210 This enables emulation of the legacy vsyscall page. Disabling 1211 it is roughly equivalent to booting with vsyscall=none, except 1212 that it will also disable the helpful warning if a program 1213 tries to use a vsyscall. With this option set to N, offending 1214 programs will just segfault, citing addresses of the form 1215 0xffffffffff600?00. 1216 1217 This option is required by many programs built before 2013, and 1218 care should be used even with newer programs if set to N. 1219 1220 Disabling this option saves about 7K of kernel size and 1221 possibly 4K of additional runtime pagetable memory. 1222 1223config X86_IOPL_IOPERM 1224 bool "IOPERM and IOPL Emulation" 1225 default y 1226 help 1227 This enables the ioperm() and iopl() syscalls which are necessary 1228 for legacy applications. 1229 1230 Legacy IOPL support is an overbroad mechanism which allows user 1231 space aside of accessing all 65536 I/O ports also to disable 1232 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1233 capabilities and permission from potentially active security 1234 modules. 1235 1236 The emulation restricts the functionality of the syscall to 1237 only allowing the full range I/O port access, but prevents the 1238 ability to disable interrupts from user space which would be 1239 granted if the hardware IOPL mechanism would be used. 1240 1241config TOSHIBA 1242 tristate "Toshiba Laptop support" 1243 depends on X86_32 1244 help 1245 This adds a driver to safely access the System Management Mode of 1246 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1247 not work on models with a Phoenix BIOS. The System Management Mode 1248 is used to set the BIOS and power saving options on Toshiba portables. 1249 1250 For information on utilities to make use of this driver see the 1251 Toshiba Linux utilities web site at: 1252 <http://www.buzzard.org.uk/toshiba/>. 1253 1254 Say Y if you intend to run this kernel on a Toshiba portable. 1255 Say N otherwise. 1256 1257config I8K 1258 tristate "Dell i8k legacy laptop support" 1259 select HWMON 1260 select SENSORS_DELL_SMM 1261 help 1262 This option enables legacy /proc/i8k userspace interface in hwmon 1263 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1264 temperature and allows controlling fan speeds of Dell laptops via 1265 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1266 it reports also power and hotkey status. For fan speed control is 1267 needed userspace package i8kutils. 1268 1269 Say Y if you intend to run this kernel on old Dell laptops or want to 1270 use userspace package i8kutils. 1271 Say N otherwise. 1272 1273config X86_REBOOTFIXUPS 1274 bool "Enable X86 board specific fixups for reboot" 1275 depends on X86_32 1276 help 1277 This enables chipset and/or board specific fixups to be done 1278 in order to get reboot to work correctly. This is only needed on 1279 some combinations of hardware and BIOS. The symptom, for which 1280 this config is intended, is when reboot ends with a stalled/hung 1281 system. 1282 1283 Currently, the only fixup is for the Geode machines using 1284 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1285 1286 Say Y if you want to enable the fixup. Currently, it's safe to 1287 enable this option even if you don't need it. 1288 Say N otherwise. 1289 1290config MICROCODE 1291 bool "CPU microcode loading support" 1292 default y 1293 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1294 help 1295 If you say Y here, you will be able to update the microcode on 1296 Intel and AMD processors. The Intel support is for the IA32 family, 1297 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1298 AMD support is for families 0x10 and later. You will obviously need 1299 the actual microcode binary data itself which is not shipped with 1300 the Linux kernel. 1301 1302 The preferred method to load microcode from a detached initrd is described 1303 in Documentation/x86/microcode.rst. For that you need to enable 1304 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1305 initrd for microcode blobs. 1306 1307 In addition, you can build the microcode into the kernel. For that you 1308 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1309 config option. 1310 1311config MICROCODE_INTEL 1312 bool "Intel microcode loading support" 1313 depends on MICROCODE 1314 default MICROCODE 1315 help 1316 This options enables microcode patch loading support for Intel 1317 processors. 1318 1319 For the current Intel microcode data package go to 1320 <https://downloadcenter.intel.com> and search for 1321 'Linux Processor Microcode Data File'. 1322 1323config MICROCODE_AMD 1324 bool "AMD microcode loading support" 1325 depends on MICROCODE 1326 help 1327 If you select this option, microcode patch loading support for AMD 1328 processors will be enabled. 1329 1330config MICROCODE_OLD_INTERFACE 1331 bool "Ancient loading interface (DEPRECATED)" 1332 default n 1333 depends on MICROCODE 1334 help 1335 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1336 which was used by userspace tools like iucode_tool and microcode.ctl. 1337 It is inadequate because it runs too late to be able to properly 1338 load microcode on a machine and it needs special tools. Instead, you 1339 should've switched to the early loading method with the initrd or 1340 builtin microcode by now: Documentation/x86/microcode.rst 1341 1342config X86_MSR 1343 tristate "/dev/cpu/*/msr - Model-specific register support" 1344 help 1345 This device gives privileged processes access to the x86 1346 Model-Specific Registers (MSRs). It is a character device with 1347 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1348 MSR accesses are directed to a specific CPU on multi-processor 1349 systems. 1350 1351config X86_CPUID 1352 tristate "/dev/cpu/*/cpuid - CPU information support" 1353 help 1354 This device gives processes access to the x86 CPUID instruction to 1355 be executed on a specific processor. It is a character device 1356 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1357 /dev/cpu/31/cpuid. 1358 1359choice 1360 prompt "High Memory Support" 1361 default HIGHMEM4G 1362 depends on X86_32 1363 1364config NOHIGHMEM 1365 bool "off" 1366 help 1367 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1368 However, the address space of 32-bit x86 processors is only 4 1369 Gigabytes large. That means that, if you have a large amount of 1370 physical memory, not all of it can be "permanently mapped" by the 1371 kernel. The physical memory that's not permanently mapped is called 1372 "high memory". 1373 1374 If you are compiling a kernel which will never run on a machine with 1375 more than 1 Gigabyte total physical RAM, answer "off" here (default 1376 choice and suitable for most users). This will result in a "3GB/1GB" 1377 split: 3GB are mapped so that each process sees a 3GB virtual memory 1378 space and the remaining part of the 4GB virtual memory space is used 1379 by the kernel to permanently map as much physical memory as 1380 possible. 1381 1382 If the machine has between 1 and 4 Gigabytes physical RAM, then 1383 answer "4GB" here. 1384 1385 If more than 4 Gigabytes is used then answer "64GB" here. This 1386 selection turns Intel PAE (Physical Address Extension) mode on. 1387 PAE implements 3-level paging on IA32 processors. PAE is fully 1388 supported by Linux, PAE mode is implemented on all recent Intel 1389 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1390 then the kernel will not boot on CPUs that don't support PAE! 1391 1392 The actual amount of total physical memory will either be 1393 auto detected or can be forced by using a kernel command line option 1394 such as "mem=256M". (Try "man bootparam" or see the documentation of 1395 your boot loader (lilo or loadlin) about how to pass options to the 1396 kernel at boot time.) 1397 1398 If unsure, say "off". 1399 1400config HIGHMEM4G 1401 bool "4GB" 1402 help 1403 Select this if you have a 32-bit processor and between 1 and 4 1404 gigabytes of physical RAM. 1405 1406config HIGHMEM64G 1407 bool "64GB" 1408 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1409 select X86_PAE 1410 help 1411 Select this if you have a 32-bit processor and more than 4 1412 gigabytes of physical RAM. 1413 1414endchoice 1415 1416choice 1417 prompt "Memory split" if EXPERT 1418 default VMSPLIT_3G 1419 depends on X86_32 1420 help 1421 Select the desired split between kernel and user memory. 1422 1423 If the address range available to the kernel is less than the 1424 physical memory installed, the remaining memory will be available 1425 as "high memory". Accessing high memory is a little more costly 1426 than low memory, as it needs to be mapped into the kernel first. 1427 Note that increasing the kernel address space limits the range 1428 available to user programs, making the address space there 1429 tighter. Selecting anything other than the default 3G/1G split 1430 will also likely make your kernel incompatible with binary-only 1431 kernel modules. 1432 1433 If you are not absolutely sure what you are doing, leave this 1434 option alone! 1435 1436 config VMSPLIT_3G 1437 bool "3G/1G user/kernel split" 1438 config VMSPLIT_3G_OPT 1439 depends on !X86_PAE 1440 bool "3G/1G user/kernel split (for full 1G low memory)" 1441 config VMSPLIT_2G 1442 bool "2G/2G user/kernel split" 1443 config VMSPLIT_2G_OPT 1444 depends on !X86_PAE 1445 bool "2G/2G user/kernel split (for full 2G low memory)" 1446 config VMSPLIT_1G 1447 bool "1G/3G user/kernel split" 1448endchoice 1449 1450config PAGE_OFFSET 1451 hex 1452 default 0xB0000000 if VMSPLIT_3G_OPT 1453 default 0x80000000 if VMSPLIT_2G 1454 default 0x78000000 if VMSPLIT_2G_OPT 1455 default 0x40000000 if VMSPLIT_1G 1456 default 0xC0000000 1457 depends on X86_32 1458 1459config HIGHMEM 1460 def_bool y 1461 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1462 1463config X86_PAE 1464 bool "PAE (Physical Address Extension) Support" 1465 depends on X86_32 && !HIGHMEM4G 1466 select PHYS_ADDR_T_64BIT 1467 select SWIOTLB 1468 help 1469 PAE is required for NX support, and furthermore enables 1470 larger swapspace support for non-overcommit purposes. It 1471 has the cost of more pagetable lookup overhead, and also 1472 consumes more pagetable space per process. 1473 1474config X86_5LEVEL 1475 bool "Enable 5-level page tables support" 1476 default y 1477 select DYNAMIC_MEMORY_LAYOUT 1478 select SPARSEMEM_VMEMMAP 1479 depends on X86_64 1480 help 1481 5-level paging enables access to larger address space: 1482 upto 128 PiB of virtual address space and 4 PiB of 1483 physical address space. 1484 1485 It will be supported by future Intel CPUs. 1486 1487 A kernel with the option enabled can be booted on machines that 1488 support 4- or 5-level paging. 1489 1490 See Documentation/x86/x86_64/5level-paging.rst for more 1491 information. 1492 1493 Say N if unsure. 1494 1495config X86_DIRECT_GBPAGES 1496 def_bool y 1497 depends on X86_64 1498 help 1499 Certain kernel features effectively disable kernel 1500 linear 1 GB mappings (even if the CPU otherwise 1501 supports them), so don't confuse the user by printing 1502 that we have them enabled. 1503 1504config X86_CPA_STATISTICS 1505 bool "Enable statistic for Change Page Attribute" 1506 depends on DEBUG_FS 1507 help 1508 Expose statistics about the Change Page Attribute mechanism, which 1509 helps to determine the effectiveness of preserving large and huge 1510 page mappings when mapping protections are changed. 1511 1512config AMD_MEM_ENCRYPT 1513 bool "AMD Secure Memory Encryption (SME) support" 1514 depends on X86_64 && CPU_SUP_AMD 1515 select DMA_COHERENT_POOL 1516 select DYNAMIC_PHYSICAL_MASK 1517 select ARCH_USE_MEMREMAP_PROT 1518 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1519 select INSTRUCTION_DECODER 1520 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 1521 help 1522 Say yes to enable support for the encryption of system memory. 1523 This requires an AMD processor that supports Secure Memory 1524 Encryption (SME). 1525 1526config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1527 bool "Activate AMD Secure Memory Encryption (SME) by default" 1528 default y 1529 depends on AMD_MEM_ENCRYPT 1530 help 1531 Say yes to have system memory encrypted by default if running on 1532 an AMD processor that supports Secure Memory Encryption (SME). 1533 1534 If set to Y, then the encryption of system memory can be 1535 deactivated with the mem_encrypt=off command line option. 1536 1537 If set to N, then the encryption of system memory can be 1538 activated with the mem_encrypt=on command line option. 1539 1540# Common NUMA Features 1541config NUMA 1542 bool "NUMA Memory Allocation and Scheduler Support" 1543 depends on SMP 1544 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1545 default y if X86_BIGSMP 1546 help 1547 Enable NUMA (Non-Uniform Memory Access) support. 1548 1549 The kernel will try to allocate memory used by a CPU on the 1550 local memory controller of the CPU and add some more 1551 NUMA awareness to the kernel. 1552 1553 For 64-bit this is recommended if the system is Intel Core i7 1554 (or later), AMD Opteron, or EM64T NUMA. 1555 1556 For 32-bit this is only needed if you boot a 32-bit 1557 kernel on a 64-bit NUMA platform. 1558 1559 Otherwise, you should say N. 1560 1561config AMD_NUMA 1562 def_bool y 1563 prompt "Old style AMD Opteron NUMA detection" 1564 depends on X86_64 && NUMA && PCI 1565 help 1566 Enable AMD NUMA node topology detection. You should say Y here if 1567 you have a multi processor AMD system. This uses an old method to 1568 read the NUMA configuration directly from the builtin Northbridge 1569 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1570 which also takes priority if both are compiled in. 1571 1572config X86_64_ACPI_NUMA 1573 def_bool y 1574 prompt "ACPI NUMA detection" 1575 depends on X86_64 && NUMA && ACPI && PCI 1576 select ACPI_NUMA 1577 help 1578 Enable ACPI SRAT based node topology detection. 1579 1580config NUMA_EMU 1581 bool "NUMA emulation" 1582 depends on NUMA 1583 help 1584 Enable NUMA emulation. A flat machine will be split 1585 into virtual nodes when booted with "numa=fake=N", where N is the 1586 number of nodes. This is only useful for debugging. 1587 1588config NODES_SHIFT 1589 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1590 range 1 10 1591 default "10" if MAXSMP 1592 default "6" if X86_64 1593 default "3" 1594 depends on NUMA 1595 help 1596 Specify the maximum number of NUMA Nodes available on the target 1597 system. Increases memory reserved to accommodate various tables. 1598 1599config ARCH_FLATMEM_ENABLE 1600 def_bool y 1601 depends on X86_32 && !NUMA 1602 1603config ARCH_SPARSEMEM_ENABLE 1604 def_bool y 1605 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1606 select SPARSEMEM_STATIC if X86_32 1607 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1608 1609config ARCH_SPARSEMEM_DEFAULT 1610 def_bool X86_64 || (NUMA && X86_32) 1611 1612config ARCH_SELECT_MEMORY_MODEL 1613 def_bool y 1614 depends on ARCH_SPARSEMEM_ENABLE 1615 1616config ARCH_MEMORY_PROBE 1617 bool "Enable sysfs memory/probe interface" 1618 depends on X86_64 && MEMORY_HOTPLUG 1619 help 1620 This option enables a sysfs memory/probe interface for testing. 1621 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1622 If you are unsure how to answer this question, answer N. 1623 1624config ARCH_PROC_KCORE_TEXT 1625 def_bool y 1626 depends on X86_64 && PROC_KCORE 1627 1628config ILLEGAL_POINTER_VALUE 1629 hex 1630 default 0 if X86_32 1631 default 0xdead000000000000 if X86_64 1632 1633config X86_PMEM_LEGACY_DEVICE 1634 bool 1635 1636config X86_PMEM_LEGACY 1637 tristate "Support non-standard NVDIMMs and ADR protected memory" 1638 depends on PHYS_ADDR_T_64BIT 1639 depends on BLK_DEV 1640 select X86_PMEM_LEGACY_DEVICE 1641 select NUMA_KEEP_MEMINFO if NUMA 1642 select LIBNVDIMM 1643 help 1644 Treat memory marked using the non-standard e820 type of 12 as used 1645 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1646 The kernel will offer these regions to the 'pmem' driver so 1647 they can be used for persistent storage. 1648 1649 Say Y if unsure. 1650 1651config HIGHPTE 1652 bool "Allocate 3rd-level pagetables from highmem" 1653 depends on HIGHMEM 1654 help 1655 The VM uses one page table entry for each page of physical memory. 1656 For systems with a lot of RAM, this can be wasteful of precious 1657 low memory. Setting this option will put user-space page table 1658 entries in high memory. 1659 1660config X86_CHECK_BIOS_CORRUPTION 1661 bool "Check for low memory corruption" 1662 help 1663 Periodically check for memory corruption in low memory, which 1664 is suspected to be caused by BIOS. Even when enabled in the 1665 configuration, it is disabled at runtime. Enable it by 1666 setting "memory_corruption_check=1" on the kernel command 1667 line. By default it scans the low 64k of memory every 60 1668 seconds; see the memory_corruption_check_size and 1669 memory_corruption_check_period parameters in 1670 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1671 1672 When enabled with the default parameters, this option has 1673 almost no overhead, as it reserves a relatively small amount 1674 of memory and scans it infrequently. It both detects corruption 1675 and prevents it from affecting the running system. 1676 1677 It is, however, intended as a diagnostic tool; if repeatable 1678 BIOS-originated corruption always affects the same memory, 1679 you can use memmap= to prevent the kernel from using that 1680 memory. 1681 1682config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1683 bool "Set the default setting of memory_corruption_check" 1684 depends on X86_CHECK_BIOS_CORRUPTION 1685 default y 1686 help 1687 Set whether the default state of memory_corruption_check is 1688 on or off. 1689 1690config MATH_EMULATION 1691 bool 1692 depends on MODIFY_LDT_SYSCALL 1693 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1694 help 1695 Linux can emulate a math coprocessor (used for floating point 1696 operations) if you don't have one. 486DX and Pentium processors have 1697 a math coprocessor built in, 486SX and 386 do not, unless you added 1698 a 487DX or 387, respectively. (The messages during boot time can 1699 give you some hints here ["man dmesg"].) Everyone needs either a 1700 coprocessor or this emulation. 1701 1702 If you don't have a math coprocessor, you need to say Y here; if you 1703 say Y here even though you have a coprocessor, the coprocessor will 1704 be used nevertheless. (This behavior can be changed with the kernel 1705 command line option "no387", which comes handy if your coprocessor 1706 is broken. Try "man bootparam" or see the documentation of your boot 1707 loader (lilo or loadlin) about how to pass options to the kernel at 1708 boot time.) This means that it is a good idea to say Y here if you 1709 intend to use this kernel on different machines. 1710 1711 More information about the internals of the Linux math coprocessor 1712 emulation can be found in <file:arch/x86/math-emu/README>. 1713 1714 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1715 kernel, it won't hurt. 1716 1717config MTRR 1718 def_bool y 1719 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1720 help 1721 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1722 the Memory Type Range Registers (MTRRs) may be used to control 1723 processor access to memory ranges. This is most useful if you have 1724 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1725 allows bus write transfers to be combined into a larger transfer 1726 before bursting over the PCI/AGP bus. This can increase performance 1727 of image write operations 2.5 times or more. Saying Y here creates a 1728 /proc/mtrr file which may be used to manipulate your processor's 1729 MTRRs. Typically the X server should use this. 1730 1731 This code has a reasonably generic interface so that similar 1732 control registers on other processors can be easily supported 1733 as well: 1734 1735 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1736 Registers (ARRs) which provide a similar functionality to MTRRs. For 1737 these, the ARRs are used to emulate the MTRRs. 1738 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1739 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1740 write-combining. All of these processors are supported by this code 1741 and it makes sense to say Y here if you have one of them. 1742 1743 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1744 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1745 can lead to all sorts of problems, so it's good to say Y here. 1746 1747 You can safely say Y even if your machine doesn't have MTRRs, you'll 1748 just add about 9 KB to your kernel. 1749 1750 See <file:Documentation/x86/mtrr.rst> for more information. 1751 1752config MTRR_SANITIZER 1753 def_bool y 1754 prompt "MTRR cleanup support" 1755 depends on MTRR 1756 help 1757 Convert MTRR layout from continuous to discrete, so X drivers can 1758 add writeback entries. 1759 1760 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1761 The largest mtrr entry size for a continuous block can be set with 1762 mtrr_chunk_size. 1763 1764 If unsure, say Y. 1765 1766config MTRR_SANITIZER_ENABLE_DEFAULT 1767 int "MTRR cleanup enable value (0-1)" 1768 range 0 1 1769 default "0" 1770 depends on MTRR_SANITIZER 1771 help 1772 Enable mtrr cleanup default value 1773 1774config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1775 int "MTRR cleanup spare reg num (0-7)" 1776 range 0 7 1777 default "1" 1778 depends on MTRR_SANITIZER 1779 help 1780 mtrr cleanup spare entries default, it can be changed via 1781 mtrr_spare_reg_nr=N on the kernel command line. 1782 1783config X86_PAT 1784 def_bool y 1785 prompt "x86 PAT support" if EXPERT 1786 depends on MTRR 1787 help 1788 Use PAT attributes to setup page level cache control. 1789 1790 PATs are the modern equivalents of MTRRs and are much more 1791 flexible than MTRRs. 1792 1793 Say N here if you see bootup problems (boot crash, boot hang, 1794 spontaneous reboots) or a non-working video driver. 1795 1796 If unsure, say Y. 1797 1798config ARCH_USES_PG_UNCACHED 1799 def_bool y 1800 depends on X86_PAT 1801 1802config ARCH_RANDOM 1803 def_bool y 1804 prompt "x86 architectural random number generator" if EXPERT 1805 help 1806 Enable the x86 architectural RDRAND instruction 1807 (Intel Bull Mountain technology) to generate random numbers. 1808 If supported, this is a high bandwidth, cryptographically 1809 secure hardware random number generator. 1810 1811config X86_SMAP 1812 def_bool y 1813 prompt "Supervisor Mode Access Prevention" if EXPERT 1814 help 1815 Supervisor Mode Access Prevention (SMAP) is a security 1816 feature in newer Intel processors. There is a small 1817 performance cost if this enabled and turned on; there is 1818 also a small increase in the kernel size if this is enabled. 1819 1820 If unsure, say Y. 1821 1822config X86_UMIP 1823 def_bool y 1824 prompt "User Mode Instruction Prevention" if EXPERT 1825 help 1826 User Mode Instruction Prevention (UMIP) is a security feature in 1827 some x86 processors. If enabled, a general protection fault is 1828 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1829 executed in user mode. These instructions unnecessarily expose 1830 information about the hardware state. 1831 1832 The vast majority of applications do not use these instructions. 1833 For the very few that do, software emulation is provided in 1834 specific cases in protected and virtual-8086 modes. Emulated 1835 results are dummy. 1836 1837config X86_INTEL_MEMORY_PROTECTION_KEYS 1838 prompt "Memory Protection Keys" 1839 def_bool y 1840 # Note: only available in 64-bit mode 1841 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1842 select ARCH_USES_HIGH_VMA_FLAGS 1843 select ARCH_HAS_PKEYS 1844 help 1845 Memory Protection Keys provides a mechanism for enforcing 1846 page-based protections, but without requiring modification of the 1847 page tables when an application changes protection domains. 1848 1849 For details, see Documentation/core-api/protection-keys.rst 1850 1851 If unsure, say y. 1852 1853choice 1854 prompt "TSX enable mode" 1855 depends on CPU_SUP_INTEL 1856 default X86_INTEL_TSX_MODE_OFF 1857 help 1858 Intel's TSX (Transactional Synchronization Extensions) feature 1859 allows to optimize locking protocols through lock elision which 1860 can lead to a noticeable performance boost. 1861 1862 On the other hand it has been shown that TSX can be exploited 1863 to form side channel attacks (e.g. TAA) and chances are there 1864 will be more of those attacks discovered in the future. 1865 1866 Therefore TSX is not enabled by default (aka tsx=off). An admin 1867 might override this decision by tsx=on the command line parameter. 1868 Even with TSX enabled, the kernel will attempt to enable the best 1869 possible TAA mitigation setting depending on the microcode available 1870 for the particular machine. 1871 1872 This option allows to set the default tsx mode between tsx=on, =off 1873 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1874 details. 1875 1876 Say off if not sure, auto if TSX is in use but it should be used on safe 1877 platforms or on if TSX is in use and the security aspect of tsx is not 1878 relevant. 1879 1880config X86_INTEL_TSX_MODE_OFF 1881 bool "off" 1882 help 1883 TSX is disabled if possible - equals to tsx=off command line parameter. 1884 1885config X86_INTEL_TSX_MODE_ON 1886 bool "on" 1887 help 1888 TSX is always enabled on TSX capable HW - equals the tsx=on command 1889 line parameter. 1890 1891config X86_INTEL_TSX_MODE_AUTO 1892 bool "auto" 1893 help 1894 TSX is enabled on TSX capable HW that is believed to be safe against 1895 side channel attacks- equals the tsx=auto command line parameter. 1896endchoice 1897 1898config X86_SGX 1899 bool "Software Guard eXtensions (SGX)" 1900 depends on X86_64 && CPU_SUP_INTEL 1901 depends on CRYPTO=y 1902 depends on CRYPTO_SHA256=y 1903 select SRCU 1904 select MMU_NOTIFIER 1905 select NUMA_KEEP_MEMINFO if NUMA 1906 help 1907 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1908 that can be used by applications to set aside private regions of code 1909 and data, referred to as enclaves. An enclave's private memory can 1910 only be accessed by code running within the enclave. Accesses from 1911 outside the enclave, including other enclaves, are disallowed by 1912 hardware. 1913 1914 If unsure, say N. 1915 1916config EFI 1917 bool "EFI runtime service support" 1918 depends on ACPI 1919 select UCS2_STRING 1920 select EFI_RUNTIME_WRAPPERS 1921 help 1922 This enables the kernel to use EFI runtime services that are 1923 available (such as the EFI variable services). 1924 1925 This option is only useful on systems that have EFI firmware. 1926 In addition, you should use the latest ELILO loader available 1927 at <http://elilo.sourceforge.net> in order to take advantage 1928 of EFI runtime services. However, even with this option, the 1929 resultant kernel should continue to boot on existing non-EFI 1930 platforms. 1931 1932config EFI_STUB 1933 bool "EFI stub support" 1934 depends on EFI && !X86_USE_3DNOW 1935 depends on $(cc-option,-mabi=ms) || X86_32 1936 select RELOCATABLE 1937 help 1938 This kernel feature allows a bzImage to be loaded directly 1939 by EFI firmware without the use of a bootloader. 1940 1941 See Documentation/admin-guide/efi-stub.rst for more information. 1942 1943config EFI_MIXED 1944 bool "EFI mixed-mode support" 1945 depends on EFI_STUB && X86_64 1946 help 1947 Enabling this feature allows a 64-bit kernel to be booted 1948 on a 32-bit firmware, provided that your CPU supports 64-bit 1949 mode. 1950 1951 Note that it is not possible to boot a mixed-mode enabled 1952 kernel via the EFI boot stub - a bootloader that supports 1953 the EFI handover protocol must be used. 1954 1955 If unsure, say N. 1956 1957source "kernel/Kconfig.hz" 1958 1959config KEXEC 1960 bool "kexec system call" 1961 select KEXEC_CORE 1962 help 1963 kexec is a system call that implements the ability to shutdown your 1964 current kernel, and to start another kernel. It is like a reboot 1965 but it is independent of the system firmware. And like a reboot 1966 you can start any kernel with it, not just Linux. 1967 1968 The name comes from the similarity to the exec system call. 1969 1970 It is an ongoing process to be certain the hardware in a machine 1971 is properly shutdown, so do not be surprised if this code does not 1972 initially work for you. As of this writing the exact hardware 1973 interface is strongly in flux, so no good recommendation can be 1974 made. 1975 1976config KEXEC_FILE 1977 bool "kexec file based system call" 1978 select KEXEC_CORE 1979 select BUILD_BIN2C 1980 depends on X86_64 1981 depends on CRYPTO=y 1982 depends on CRYPTO_SHA256=y 1983 help 1984 This is new version of kexec system call. This system call is 1985 file based and takes file descriptors as system call argument 1986 for kernel and initramfs as opposed to list of segments as 1987 accepted by previous system call. 1988 1989config ARCH_HAS_KEXEC_PURGATORY 1990 def_bool KEXEC_FILE 1991 1992config KEXEC_SIG 1993 bool "Verify kernel signature during kexec_file_load() syscall" 1994 depends on KEXEC_FILE 1995 help 1996 1997 This option makes the kexec_file_load() syscall check for a valid 1998 signature of the kernel image. The image can still be loaded without 1999 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2000 there's a signature that we can check, then it must be valid. 2001 2002 In addition to this option, you need to enable signature 2003 verification for the corresponding kernel image type being 2004 loaded in order for this to work. 2005 2006config KEXEC_SIG_FORCE 2007 bool "Require a valid signature in kexec_file_load() syscall" 2008 depends on KEXEC_SIG 2009 help 2010 This option makes kernel signature verification mandatory for 2011 the kexec_file_load() syscall. 2012 2013config KEXEC_BZIMAGE_VERIFY_SIG 2014 bool "Enable bzImage signature verification support" 2015 depends on KEXEC_SIG 2016 depends on SIGNED_PE_FILE_VERIFICATION 2017 select SYSTEM_TRUSTED_KEYRING 2018 help 2019 Enable bzImage signature verification support. 2020 2021config CRASH_DUMP 2022 bool "kernel crash dumps" 2023 depends on X86_64 || (X86_32 && HIGHMEM) 2024 help 2025 Generate crash dump after being started by kexec. 2026 This should be normally only set in special crash dump kernels 2027 which are loaded in the main kernel with kexec-tools into 2028 a specially reserved region and then later executed after 2029 a crash by kdump/kexec. The crash dump kernel must be compiled 2030 to a memory address not used by the main kernel or BIOS using 2031 PHYSICAL_START, or it must be built as a relocatable image 2032 (CONFIG_RELOCATABLE=y). 2033 For more details see Documentation/admin-guide/kdump/kdump.rst 2034 2035config KEXEC_JUMP 2036 bool "kexec jump" 2037 depends on KEXEC && HIBERNATION 2038 help 2039 Jump between original kernel and kexeced kernel and invoke 2040 code in physical address mode via KEXEC 2041 2042config PHYSICAL_START 2043 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2044 default "0x1000000" 2045 help 2046 This gives the physical address where the kernel is loaded. 2047 2048 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2049 bzImage will decompress itself to above physical address and 2050 run from there. Otherwise, bzImage will run from the address where 2051 it has been loaded by the boot loader and will ignore above physical 2052 address. 2053 2054 In normal kdump cases one does not have to set/change this option 2055 as now bzImage can be compiled as a completely relocatable image 2056 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2057 address. This option is mainly useful for the folks who don't want 2058 to use a bzImage for capturing the crash dump and want to use a 2059 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2060 to be specifically compiled to run from a specific memory area 2061 (normally a reserved region) and this option comes handy. 2062 2063 So if you are using bzImage for capturing the crash dump, 2064 leave the value here unchanged to 0x1000000 and set 2065 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2066 for capturing the crash dump change this value to start of 2067 the reserved region. In other words, it can be set based on 2068 the "X" value as specified in the "crashkernel=YM@XM" 2069 command line boot parameter passed to the panic-ed 2070 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2071 for more details about crash dumps. 2072 2073 Usage of bzImage for capturing the crash dump is recommended as 2074 one does not have to build two kernels. Same kernel can be used 2075 as production kernel and capture kernel. Above option should have 2076 gone away after relocatable bzImage support is introduced. But it 2077 is present because there are users out there who continue to use 2078 vmlinux for dump capture. This option should go away down the 2079 line. 2080 2081 Don't change this unless you know what you are doing. 2082 2083config RELOCATABLE 2084 bool "Build a relocatable kernel" 2085 default y 2086 help 2087 This builds a kernel image that retains relocation information 2088 so it can be loaded someplace besides the default 1MB. 2089 The relocations tend to make the kernel binary about 10% larger, 2090 but are discarded at runtime. 2091 2092 One use is for the kexec on panic case where the recovery kernel 2093 must live at a different physical address than the primary 2094 kernel. 2095 2096 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2097 it has been loaded at and the compile time physical address 2098 (CONFIG_PHYSICAL_START) is used as the minimum location. 2099 2100config RANDOMIZE_BASE 2101 bool "Randomize the address of the kernel image (KASLR)" 2102 depends on RELOCATABLE 2103 default y 2104 help 2105 In support of Kernel Address Space Layout Randomization (KASLR), 2106 this randomizes the physical address at which the kernel image 2107 is decompressed and the virtual address where the kernel 2108 image is mapped, as a security feature that deters exploit 2109 attempts relying on knowledge of the location of kernel 2110 code internals. 2111 2112 On 64-bit, the kernel physical and virtual addresses are 2113 randomized separately. The physical address will be anywhere 2114 between 16MB and the top of physical memory (up to 64TB). The 2115 virtual address will be randomized from 16MB up to 1GB (9 bits 2116 of entropy). Note that this also reduces the memory space 2117 available to kernel modules from 1.5GB to 1GB. 2118 2119 On 32-bit, the kernel physical and virtual addresses are 2120 randomized together. They will be randomized from 16MB up to 2121 512MB (8 bits of entropy). 2122 2123 Entropy is generated using the RDRAND instruction if it is 2124 supported. If RDTSC is supported, its value is mixed into 2125 the entropy pool as well. If neither RDRAND nor RDTSC are 2126 supported, then entropy is read from the i8254 timer. The 2127 usable entropy is limited by the kernel being built using 2128 2GB addressing, and that PHYSICAL_ALIGN must be at a 2129 minimum of 2MB. As a result, only 10 bits of entropy are 2130 theoretically possible, but the implementations are further 2131 limited due to memory layouts. 2132 2133 If unsure, say Y. 2134 2135# Relocation on x86 needs some additional build support 2136config X86_NEED_RELOCS 2137 def_bool y 2138 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2139 2140config PHYSICAL_ALIGN 2141 hex "Alignment value to which kernel should be aligned" 2142 default "0x200000" 2143 range 0x2000 0x1000000 if X86_32 2144 range 0x200000 0x1000000 if X86_64 2145 help 2146 This value puts the alignment restrictions on physical address 2147 where kernel is loaded and run from. Kernel is compiled for an 2148 address which meets above alignment restriction. 2149 2150 If bootloader loads the kernel at a non-aligned address and 2151 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2152 address aligned to above value and run from there. 2153 2154 If bootloader loads the kernel at a non-aligned address and 2155 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2156 load address and decompress itself to the address it has been 2157 compiled for and run from there. The address for which kernel is 2158 compiled already meets above alignment restrictions. Hence the 2159 end result is that kernel runs from a physical address meeting 2160 above alignment restrictions. 2161 2162 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2163 this value must be a multiple of 0x200000. 2164 2165 Don't change this unless you know what you are doing. 2166 2167config DYNAMIC_MEMORY_LAYOUT 2168 bool 2169 help 2170 This option makes base addresses of vmalloc and vmemmap as well as 2171 __PAGE_OFFSET movable during boot. 2172 2173config RANDOMIZE_MEMORY 2174 bool "Randomize the kernel memory sections" 2175 depends on X86_64 2176 depends on RANDOMIZE_BASE 2177 select DYNAMIC_MEMORY_LAYOUT 2178 default RANDOMIZE_BASE 2179 help 2180 Randomizes the base virtual address of kernel memory sections 2181 (physical memory mapping, vmalloc & vmemmap). This security feature 2182 makes exploits relying on predictable memory locations less reliable. 2183 2184 The order of allocations remains unchanged. Entropy is generated in 2185 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2186 configuration have in average 30,000 different possible virtual 2187 addresses for each memory section. 2188 2189 If unsure, say Y. 2190 2191config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2192 hex "Physical memory mapping padding" if EXPERT 2193 depends on RANDOMIZE_MEMORY 2194 default "0xa" if MEMORY_HOTPLUG 2195 default "0x0" 2196 range 0x1 0x40 if MEMORY_HOTPLUG 2197 range 0x0 0x40 2198 help 2199 Define the padding in terabytes added to the existing physical 2200 memory size during kernel memory randomization. It is useful 2201 for memory hotplug support but reduces the entropy available for 2202 address randomization. 2203 2204 If unsure, leave at the default value. 2205 2206config HOTPLUG_CPU 2207 def_bool y 2208 depends on SMP 2209 2210config BOOTPARAM_HOTPLUG_CPU0 2211 bool "Set default setting of cpu0_hotpluggable" 2212 depends on HOTPLUG_CPU 2213 help 2214 Set whether default state of cpu0_hotpluggable is on or off. 2215 2216 Say Y here to enable CPU0 hotplug by default. If this switch 2217 is turned on, there is no need to give cpu0_hotplug kernel 2218 parameter and the CPU0 hotplug feature is enabled by default. 2219 2220 Please note: there are two known CPU0 dependencies if you want 2221 to enable the CPU0 hotplug feature either by this switch or by 2222 cpu0_hotplug kernel parameter. 2223 2224 First, resume from hibernate or suspend always starts from CPU0. 2225 So hibernate and suspend are prevented if CPU0 is offline. 2226 2227 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2228 offline if any interrupt can not migrate out of CPU0. There may 2229 be other CPU0 dependencies. 2230 2231 Please make sure the dependencies are under your control before 2232 you enable this feature. 2233 2234 Say N if you don't want to enable CPU0 hotplug feature by default. 2235 You still can enable the CPU0 hotplug feature at boot by kernel 2236 parameter cpu0_hotplug. 2237 2238config DEBUG_HOTPLUG_CPU0 2239 def_bool n 2240 prompt "Debug CPU0 hotplug" 2241 depends on HOTPLUG_CPU 2242 help 2243 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2244 soon as possible and boots up userspace with CPU0 offlined. User 2245 can online CPU0 back after boot time. 2246 2247 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2248 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2249 compilation or giving cpu0_hotplug kernel parameter at boot. 2250 2251 If unsure, say N. 2252 2253config COMPAT_VDSO 2254 def_bool n 2255 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2256 depends on COMPAT_32 2257 help 2258 Certain buggy versions of glibc will crash if they are 2259 presented with a 32-bit vDSO that is not mapped at the address 2260 indicated in its segment table. 2261 2262 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2263 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2264 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2265 the only released version with the bug, but OpenSUSE 9 2266 contains a buggy "glibc 2.3.2". 2267 2268 The symptom of the bug is that everything crashes on startup, saying: 2269 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2270 2271 Saying Y here changes the default value of the vdso32 boot 2272 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2273 This works around the glibc bug but hurts performance. 2274 2275 If unsure, say N: if you are compiling your own kernel, you 2276 are unlikely to be using a buggy version of glibc. 2277 2278choice 2279 prompt "vsyscall table for legacy applications" 2280 depends on X86_64 2281 default LEGACY_VSYSCALL_XONLY 2282 help 2283 Legacy user code that does not know how to find the vDSO expects 2284 to be able to issue three syscalls by calling fixed addresses in 2285 kernel space. Since this location is not randomized with ASLR, 2286 it can be used to assist security vulnerability exploitation. 2287 2288 This setting can be changed at boot time via the kernel command 2289 line parameter vsyscall=[emulate|xonly|none]. 2290 2291 On a system with recent enough glibc (2.14 or newer) and no 2292 static binaries, you can say None without a performance penalty 2293 to improve security. 2294 2295 If unsure, select "Emulate execution only". 2296 2297 config LEGACY_VSYSCALL_EMULATE 2298 bool "Full emulation" 2299 help 2300 The kernel traps and emulates calls into the fixed vsyscall 2301 address mapping. This makes the mapping non-executable, but 2302 it still contains readable known contents, which could be 2303 used in certain rare security vulnerability exploits. This 2304 configuration is recommended when using legacy userspace 2305 that still uses vsyscalls along with legacy binary 2306 instrumentation tools that require code to be readable. 2307 2308 An example of this type of legacy userspace is running 2309 Pin on an old binary that still uses vsyscalls. 2310 2311 config LEGACY_VSYSCALL_XONLY 2312 bool "Emulate execution only" 2313 help 2314 The kernel traps and emulates calls into the fixed vsyscall 2315 address mapping and does not allow reads. This 2316 configuration is recommended when userspace might use the 2317 legacy vsyscall area but support for legacy binary 2318 instrumentation of legacy code is not needed. It mitigates 2319 certain uses of the vsyscall area as an ASLR-bypassing 2320 buffer. 2321 2322 config LEGACY_VSYSCALL_NONE 2323 bool "None" 2324 help 2325 There will be no vsyscall mapping at all. This will 2326 eliminate any risk of ASLR bypass due to the vsyscall 2327 fixed address mapping. Attempts to use the vsyscalls 2328 will be reported to dmesg, so that either old or 2329 malicious userspace programs can be identified. 2330 2331endchoice 2332 2333config CMDLINE_BOOL 2334 bool "Built-in kernel command line" 2335 help 2336 Allow for specifying boot arguments to the kernel at 2337 build time. On some systems (e.g. embedded ones), it is 2338 necessary or convenient to provide some or all of the 2339 kernel boot arguments with the kernel itself (that is, 2340 to not rely on the boot loader to provide them.) 2341 2342 To compile command line arguments into the kernel, 2343 set this option to 'Y', then fill in the 2344 boot arguments in CONFIG_CMDLINE. 2345 2346 Systems with fully functional boot loaders (i.e. non-embedded) 2347 should leave this option set to 'N'. 2348 2349config CMDLINE 2350 string "Built-in kernel command string" 2351 depends on CMDLINE_BOOL 2352 default "" 2353 help 2354 Enter arguments here that should be compiled into the kernel 2355 image and used at boot time. If the boot loader provides a 2356 command line at boot time, it is appended to this string to 2357 form the full kernel command line, when the system boots. 2358 2359 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2360 change this behavior. 2361 2362 In most cases, the command line (whether built-in or provided 2363 by the boot loader) should specify the device for the root 2364 file system. 2365 2366config CMDLINE_OVERRIDE 2367 bool "Built-in command line overrides boot loader arguments" 2368 depends on CMDLINE_BOOL && CMDLINE != "" 2369 help 2370 Set this option to 'Y' to have the kernel ignore the boot loader 2371 command line, and use ONLY the built-in command line. 2372 2373 This is used to work around broken boot loaders. This should 2374 be set to 'N' under normal conditions. 2375 2376config MODIFY_LDT_SYSCALL 2377 bool "Enable the LDT (local descriptor table)" if EXPERT 2378 default y 2379 help 2380 Linux can allow user programs to install a per-process x86 2381 Local Descriptor Table (LDT) using the modify_ldt(2) system 2382 call. This is required to run 16-bit or segmented code such as 2383 DOSEMU or some Wine programs. It is also used by some very old 2384 threading libraries. 2385 2386 Enabling this feature adds a small amount of overhead to 2387 context switches and increases the low-level kernel attack 2388 surface. Disabling it removes the modify_ldt(2) system call. 2389 2390 Saying 'N' here may make sense for embedded or server kernels. 2391 2392source "kernel/livepatch/Kconfig" 2393 2394endmenu 2395 2396config ARCH_HAS_ADD_PAGES 2397 def_bool y 2398 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2399 2400config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2401 def_bool y 2402 2403config USE_PERCPU_NUMA_NODE_ID 2404 def_bool y 2405 depends on NUMA 2406 2407menu "Power management and ACPI options" 2408 2409config ARCH_HIBERNATION_HEADER 2410 def_bool y 2411 depends on HIBERNATION 2412 2413source "kernel/power/Kconfig" 2414 2415source "drivers/acpi/Kconfig" 2416 2417config X86_APM_BOOT 2418 def_bool y 2419 depends on APM 2420 2421menuconfig APM 2422 tristate "APM (Advanced Power Management) BIOS support" 2423 depends on X86_32 && PM_SLEEP 2424 help 2425 APM is a BIOS specification for saving power using several different 2426 techniques. This is mostly useful for battery powered laptops with 2427 APM compliant BIOSes. If you say Y here, the system time will be 2428 reset after a RESUME operation, the /proc/apm device will provide 2429 battery status information, and user-space programs will receive 2430 notification of APM "events" (e.g. battery status change). 2431 2432 If you select "Y" here, you can disable actual use of the APM 2433 BIOS by passing the "apm=off" option to the kernel at boot time. 2434 2435 Note that the APM support is almost completely disabled for 2436 machines with more than one CPU. 2437 2438 In order to use APM, you will need supporting software. For location 2439 and more information, read <file:Documentation/power/apm-acpi.rst> 2440 and the Battery Powered Linux mini-HOWTO, available from 2441 <http://www.tldp.org/docs.html#howto>. 2442 2443 This driver does not spin down disk drives (see the hdparm(8) 2444 manpage ("man 8 hdparm") for that), and it doesn't turn off 2445 VESA-compliant "green" monitors. 2446 2447 This driver does not support the TI 4000M TravelMate and the ACER 2448 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2449 desktop machines also don't have compliant BIOSes, and this driver 2450 may cause those machines to panic during the boot phase. 2451 2452 Generally, if you don't have a battery in your machine, there isn't 2453 much point in using this driver and you should say N. If you get 2454 random kernel OOPSes or reboots that don't seem to be related to 2455 anything, try disabling/enabling this option (or disabling/enabling 2456 APM in your BIOS). 2457 2458 Some other things you should try when experiencing seemingly random, 2459 "weird" problems: 2460 2461 1) make sure that you have enough swap space and that it is 2462 enabled. 2463 2) pass the "no-hlt" option to the kernel 2464 3) switch on floating point emulation in the kernel and pass 2465 the "no387" option to the kernel 2466 4) pass the "floppy=nodma" option to the kernel 2467 5) pass the "mem=4M" option to the kernel (thereby disabling 2468 all but the first 4 MB of RAM) 2469 6) make sure that the CPU is not over clocked. 2470 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2471 8) disable the cache from your BIOS settings 2472 9) install a fan for the video card or exchange video RAM 2473 10) install a better fan for the CPU 2474 11) exchange RAM chips 2475 12) exchange the motherboard. 2476 2477 To compile this driver as a module, choose M here: the 2478 module will be called apm. 2479 2480if APM 2481 2482config APM_IGNORE_USER_SUSPEND 2483 bool "Ignore USER SUSPEND" 2484 help 2485 This option will ignore USER SUSPEND requests. On machines with a 2486 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2487 series notebooks, it is necessary to say Y because of a BIOS bug. 2488 2489config APM_DO_ENABLE 2490 bool "Enable PM at boot time" 2491 help 2492 Enable APM features at boot time. From page 36 of the APM BIOS 2493 specification: "When disabled, the APM BIOS does not automatically 2494 power manage devices, enter the Standby State, enter the Suspend 2495 State, or take power saving steps in response to CPU Idle calls." 2496 This driver will make CPU Idle calls when Linux is idle (unless this 2497 feature is turned off -- see "Do CPU IDLE calls", below). This 2498 should always save battery power, but more complicated APM features 2499 will be dependent on your BIOS implementation. You may need to turn 2500 this option off if your computer hangs at boot time when using APM 2501 support, or if it beeps continuously instead of suspending. Turn 2502 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2503 T400CDT. This is off by default since most machines do fine without 2504 this feature. 2505 2506config APM_CPU_IDLE 2507 depends on CPU_IDLE 2508 bool "Make CPU Idle calls when idle" 2509 help 2510 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2511 On some machines, this can activate improved power savings, such as 2512 a slowed CPU clock rate, when the machine is idle. These idle calls 2513 are made after the idle loop has run for some length of time (e.g., 2514 333 mS). On some machines, this will cause a hang at boot time or 2515 whenever the CPU becomes idle. (On machines with more than one CPU, 2516 this option does nothing.) 2517 2518config APM_DISPLAY_BLANK 2519 bool "Enable console blanking using APM" 2520 help 2521 Enable console blanking using the APM. Some laptops can use this to 2522 turn off the LCD backlight when the screen blanker of the Linux 2523 virtual console blanks the screen. Note that this is only used by 2524 the virtual console screen blanker, and won't turn off the backlight 2525 when using the X Window system. This also doesn't have anything to 2526 do with your VESA-compliant power-saving monitor. Further, this 2527 option doesn't work for all laptops -- it might not turn off your 2528 backlight at all, or it might print a lot of errors to the console, 2529 especially if you are using gpm. 2530 2531config APM_ALLOW_INTS 2532 bool "Allow interrupts during APM BIOS calls" 2533 help 2534 Normally we disable external interrupts while we are making calls to 2535 the APM BIOS as a measure to lessen the effects of a badly behaving 2536 BIOS implementation. The BIOS should reenable interrupts if it 2537 needs to. Unfortunately, some BIOSes do not -- especially those in 2538 many of the newer IBM Thinkpads. If you experience hangs when you 2539 suspend, try setting this to Y. Otherwise, say N. 2540 2541endif # APM 2542 2543source "drivers/cpufreq/Kconfig" 2544 2545source "drivers/cpuidle/Kconfig" 2546 2547source "drivers/idle/Kconfig" 2548 2549endmenu 2550 2551 2552menu "Bus options (PCI etc.)" 2553 2554choice 2555 prompt "PCI access mode" 2556 depends on X86_32 && PCI 2557 default PCI_GOANY 2558 help 2559 On PCI systems, the BIOS can be used to detect the PCI devices and 2560 determine their configuration. However, some old PCI motherboards 2561 have BIOS bugs and may crash if this is done. Also, some embedded 2562 PCI-based systems don't have any BIOS at all. Linux can also try to 2563 detect the PCI hardware directly without using the BIOS. 2564 2565 With this option, you can specify how Linux should detect the 2566 PCI devices. If you choose "BIOS", the BIOS will be used, 2567 if you choose "Direct", the BIOS won't be used, and if you 2568 choose "MMConfig", then PCI Express MMCONFIG will be used. 2569 If you choose "Any", the kernel will try MMCONFIG, then the 2570 direct access method and falls back to the BIOS if that doesn't 2571 work. If unsure, go with the default, which is "Any". 2572 2573config PCI_GOBIOS 2574 bool "BIOS" 2575 2576config PCI_GOMMCONFIG 2577 bool "MMConfig" 2578 2579config PCI_GODIRECT 2580 bool "Direct" 2581 2582config PCI_GOOLPC 2583 bool "OLPC XO-1" 2584 depends on OLPC 2585 2586config PCI_GOANY 2587 bool "Any" 2588 2589endchoice 2590 2591config PCI_BIOS 2592 def_bool y 2593 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2594 2595# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2596config PCI_DIRECT 2597 def_bool y 2598 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2599 2600config PCI_MMCONFIG 2601 bool "Support mmconfig PCI config space access" if X86_64 2602 default y 2603 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2604 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2605 2606config PCI_OLPC 2607 def_bool y 2608 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2609 2610config PCI_XEN 2611 def_bool y 2612 depends on PCI && XEN 2613 select SWIOTLB_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