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 && !MWINCHIP3D && !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 depends on AMD_MEM_ENCRYPT 1529 help 1530 Say yes to have system memory encrypted by default if running on 1531 an AMD processor that supports Secure Memory Encryption (SME). 1532 1533 If set to Y, then the encryption of system memory can be 1534 deactivated with the mem_encrypt=off command line option. 1535 1536 If set to N, then the encryption of system memory can be 1537 activated with the mem_encrypt=on command line option. 1538 1539# Common NUMA Features 1540config NUMA 1541 bool "NUMA Memory Allocation and Scheduler Support" 1542 depends on SMP 1543 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1544 default y if X86_BIGSMP 1545 help 1546 Enable NUMA (Non-Uniform Memory Access) support. 1547 1548 The kernel will try to allocate memory used by a CPU on the 1549 local memory controller of the CPU and add some more 1550 NUMA awareness to the kernel. 1551 1552 For 64-bit this is recommended if the system is Intel Core i7 1553 (or later), AMD Opteron, or EM64T NUMA. 1554 1555 For 32-bit this is only needed if you boot a 32-bit 1556 kernel on a 64-bit NUMA platform. 1557 1558 Otherwise, you should say N. 1559 1560config AMD_NUMA 1561 def_bool y 1562 prompt "Old style AMD Opteron NUMA detection" 1563 depends on X86_64 && NUMA && PCI 1564 help 1565 Enable AMD NUMA node topology detection. You should say Y here if 1566 you have a multi processor AMD system. This uses an old method to 1567 read the NUMA configuration directly from the builtin Northbridge 1568 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1569 which also takes priority if both are compiled in. 1570 1571config X86_64_ACPI_NUMA 1572 def_bool y 1573 prompt "ACPI NUMA detection" 1574 depends on X86_64 && NUMA && ACPI && PCI 1575 select ACPI_NUMA 1576 help 1577 Enable ACPI SRAT based node topology detection. 1578 1579config NUMA_EMU 1580 bool "NUMA emulation" 1581 depends on NUMA 1582 help 1583 Enable NUMA emulation. A flat machine will be split 1584 into virtual nodes when booted with "numa=fake=N", where N is the 1585 number of nodes. This is only useful for debugging. 1586 1587config NODES_SHIFT 1588 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1589 range 1 10 1590 default "10" if MAXSMP 1591 default "6" if X86_64 1592 default "3" 1593 depends on NUMA 1594 help 1595 Specify the maximum number of NUMA Nodes available on the target 1596 system. Increases memory reserved to accommodate various tables. 1597 1598config ARCH_FLATMEM_ENABLE 1599 def_bool y 1600 depends on X86_32 && !NUMA 1601 1602config ARCH_SPARSEMEM_ENABLE 1603 def_bool y 1604 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1605 select SPARSEMEM_STATIC if X86_32 1606 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1607 1608config ARCH_SPARSEMEM_DEFAULT 1609 def_bool X86_64 || (NUMA && X86_32) 1610 1611config ARCH_SELECT_MEMORY_MODEL 1612 def_bool y 1613 depends on ARCH_SPARSEMEM_ENABLE 1614 1615config ARCH_MEMORY_PROBE 1616 bool "Enable sysfs memory/probe interface" 1617 depends on X86_64 && MEMORY_HOTPLUG 1618 help 1619 This option enables a sysfs memory/probe interface for testing. 1620 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1621 If you are unsure how to answer this question, answer N. 1622 1623config ARCH_PROC_KCORE_TEXT 1624 def_bool y 1625 depends on X86_64 && PROC_KCORE 1626 1627config ILLEGAL_POINTER_VALUE 1628 hex 1629 default 0 if X86_32 1630 default 0xdead000000000000 if X86_64 1631 1632config X86_PMEM_LEGACY_DEVICE 1633 bool 1634 1635config X86_PMEM_LEGACY 1636 tristate "Support non-standard NVDIMMs and ADR protected memory" 1637 depends on PHYS_ADDR_T_64BIT 1638 depends on BLK_DEV 1639 select X86_PMEM_LEGACY_DEVICE 1640 select NUMA_KEEP_MEMINFO if NUMA 1641 select LIBNVDIMM 1642 help 1643 Treat memory marked using the non-standard e820 type of 12 as used 1644 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1645 The kernel will offer these regions to the 'pmem' driver so 1646 they can be used for persistent storage. 1647 1648 Say Y if unsure. 1649 1650config HIGHPTE 1651 bool "Allocate 3rd-level pagetables from highmem" 1652 depends on HIGHMEM 1653 help 1654 The VM uses one page table entry for each page of physical memory. 1655 For systems with a lot of RAM, this can be wasteful of precious 1656 low memory. Setting this option will put user-space page table 1657 entries in high memory. 1658 1659config X86_CHECK_BIOS_CORRUPTION 1660 bool "Check for low memory corruption" 1661 help 1662 Periodically check for memory corruption in low memory, which 1663 is suspected to be caused by BIOS. Even when enabled in the 1664 configuration, it is disabled at runtime. Enable it by 1665 setting "memory_corruption_check=1" on the kernel command 1666 line. By default it scans the low 64k of memory every 60 1667 seconds; see the memory_corruption_check_size and 1668 memory_corruption_check_period parameters in 1669 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1670 1671 When enabled with the default parameters, this option has 1672 almost no overhead, as it reserves a relatively small amount 1673 of memory and scans it infrequently. It both detects corruption 1674 and prevents it from affecting the running system. 1675 1676 It is, however, intended as a diagnostic tool; if repeatable 1677 BIOS-originated corruption always affects the same memory, 1678 you can use memmap= to prevent the kernel from using that 1679 memory. 1680 1681config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1682 bool "Set the default setting of memory_corruption_check" 1683 depends on X86_CHECK_BIOS_CORRUPTION 1684 default y 1685 help 1686 Set whether the default state of memory_corruption_check is 1687 on or off. 1688 1689config MATH_EMULATION 1690 bool 1691 depends on MODIFY_LDT_SYSCALL 1692 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1693 help 1694 Linux can emulate a math coprocessor (used for floating point 1695 operations) if you don't have one. 486DX and Pentium processors have 1696 a math coprocessor built in, 486SX and 386 do not, unless you added 1697 a 487DX or 387, respectively. (The messages during boot time can 1698 give you some hints here ["man dmesg"].) Everyone needs either a 1699 coprocessor or this emulation. 1700 1701 If you don't have a math coprocessor, you need to say Y here; if you 1702 say Y here even though you have a coprocessor, the coprocessor will 1703 be used nevertheless. (This behavior can be changed with the kernel 1704 command line option "no387", which comes handy if your coprocessor 1705 is broken. Try "man bootparam" or see the documentation of your boot 1706 loader (lilo or loadlin) about how to pass options to the kernel at 1707 boot time.) This means that it is a good idea to say Y here if you 1708 intend to use this kernel on different machines. 1709 1710 More information about the internals of the Linux math coprocessor 1711 emulation can be found in <file:arch/x86/math-emu/README>. 1712 1713 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1714 kernel, it won't hurt. 1715 1716config MTRR 1717 def_bool y 1718 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1719 help 1720 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1721 the Memory Type Range Registers (MTRRs) may be used to control 1722 processor access to memory ranges. This is most useful if you have 1723 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1724 allows bus write transfers to be combined into a larger transfer 1725 before bursting over the PCI/AGP bus. This can increase performance 1726 of image write operations 2.5 times or more. Saying Y here creates a 1727 /proc/mtrr file which may be used to manipulate your processor's 1728 MTRRs. Typically the X server should use this. 1729 1730 This code has a reasonably generic interface so that similar 1731 control registers on other processors can be easily supported 1732 as well: 1733 1734 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1735 Registers (ARRs) which provide a similar functionality to MTRRs. For 1736 these, the ARRs are used to emulate the MTRRs. 1737 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1738 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1739 write-combining. All of these processors are supported by this code 1740 and it makes sense to say Y here if you have one of them. 1741 1742 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1743 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1744 can lead to all sorts of problems, so it's good to say Y here. 1745 1746 You can safely say Y even if your machine doesn't have MTRRs, you'll 1747 just add about 9 KB to your kernel. 1748 1749 See <file:Documentation/x86/mtrr.rst> for more information. 1750 1751config MTRR_SANITIZER 1752 def_bool y 1753 prompt "MTRR cleanup support" 1754 depends on MTRR 1755 help 1756 Convert MTRR layout from continuous to discrete, so X drivers can 1757 add writeback entries. 1758 1759 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1760 The largest mtrr entry size for a continuous block can be set with 1761 mtrr_chunk_size. 1762 1763 If unsure, say Y. 1764 1765config MTRR_SANITIZER_ENABLE_DEFAULT 1766 int "MTRR cleanup enable value (0-1)" 1767 range 0 1 1768 default "0" 1769 depends on MTRR_SANITIZER 1770 help 1771 Enable mtrr cleanup default value 1772 1773config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1774 int "MTRR cleanup spare reg num (0-7)" 1775 range 0 7 1776 default "1" 1777 depends on MTRR_SANITIZER 1778 help 1779 mtrr cleanup spare entries default, it can be changed via 1780 mtrr_spare_reg_nr=N on the kernel command line. 1781 1782config X86_PAT 1783 def_bool y 1784 prompt "x86 PAT support" if EXPERT 1785 depends on MTRR 1786 help 1787 Use PAT attributes to setup page level cache control. 1788 1789 PATs are the modern equivalents of MTRRs and are much more 1790 flexible than MTRRs. 1791 1792 Say N here if you see bootup problems (boot crash, boot hang, 1793 spontaneous reboots) or a non-working video driver. 1794 1795 If unsure, say Y. 1796 1797config ARCH_USES_PG_UNCACHED 1798 def_bool y 1799 depends on X86_PAT 1800 1801config ARCH_RANDOM 1802 def_bool y 1803 prompt "x86 architectural random number generator" if EXPERT 1804 help 1805 Enable the x86 architectural RDRAND instruction 1806 (Intel Bull Mountain technology) to generate random numbers. 1807 If supported, this is a high bandwidth, cryptographically 1808 secure hardware random number generator. 1809 1810config X86_SMAP 1811 def_bool y 1812 prompt "Supervisor Mode Access Prevention" if EXPERT 1813 help 1814 Supervisor Mode Access Prevention (SMAP) is a security 1815 feature in newer Intel processors. There is a small 1816 performance cost if this enabled and turned on; there is 1817 also a small increase in the kernel size if this is enabled. 1818 1819 If unsure, say Y. 1820 1821config X86_UMIP 1822 def_bool y 1823 prompt "User Mode Instruction Prevention" if EXPERT 1824 help 1825 User Mode Instruction Prevention (UMIP) is a security feature in 1826 some x86 processors. If enabled, a general protection fault is 1827 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1828 executed in user mode. These instructions unnecessarily expose 1829 information about the hardware state. 1830 1831 The vast majority of applications do not use these instructions. 1832 For the very few that do, software emulation is provided in 1833 specific cases in protected and virtual-8086 modes. Emulated 1834 results are dummy. 1835 1836config X86_INTEL_MEMORY_PROTECTION_KEYS 1837 prompt "Memory Protection Keys" 1838 def_bool y 1839 # Note: only available in 64-bit mode 1840 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1841 select ARCH_USES_HIGH_VMA_FLAGS 1842 select ARCH_HAS_PKEYS 1843 help 1844 Memory Protection Keys provides a mechanism for enforcing 1845 page-based protections, but without requiring modification of the 1846 page tables when an application changes protection domains. 1847 1848 For details, see Documentation/core-api/protection-keys.rst 1849 1850 If unsure, say y. 1851 1852choice 1853 prompt "TSX enable mode" 1854 depends on CPU_SUP_INTEL 1855 default X86_INTEL_TSX_MODE_OFF 1856 help 1857 Intel's TSX (Transactional Synchronization Extensions) feature 1858 allows to optimize locking protocols through lock elision which 1859 can lead to a noticeable performance boost. 1860 1861 On the other hand it has been shown that TSX can be exploited 1862 to form side channel attacks (e.g. TAA) and chances are there 1863 will be more of those attacks discovered in the future. 1864 1865 Therefore TSX is not enabled by default (aka tsx=off). An admin 1866 might override this decision by tsx=on the command line parameter. 1867 Even with TSX enabled, the kernel will attempt to enable the best 1868 possible TAA mitigation setting depending on the microcode available 1869 for the particular machine. 1870 1871 This option allows to set the default tsx mode between tsx=on, =off 1872 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1873 details. 1874 1875 Say off if not sure, auto if TSX is in use but it should be used on safe 1876 platforms or on if TSX is in use and the security aspect of tsx is not 1877 relevant. 1878 1879config X86_INTEL_TSX_MODE_OFF 1880 bool "off" 1881 help 1882 TSX is disabled if possible - equals to tsx=off command line parameter. 1883 1884config X86_INTEL_TSX_MODE_ON 1885 bool "on" 1886 help 1887 TSX is always enabled on TSX capable HW - equals the tsx=on command 1888 line parameter. 1889 1890config X86_INTEL_TSX_MODE_AUTO 1891 bool "auto" 1892 help 1893 TSX is enabled on TSX capable HW that is believed to be safe against 1894 side channel attacks- equals the tsx=auto command line parameter. 1895endchoice 1896 1897config X86_SGX 1898 bool "Software Guard eXtensions (SGX)" 1899 depends on X86_64 && CPU_SUP_INTEL 1900 depends on CRYPTO=y 1901 depends on CRYPTO_SHA256=y 1902 select SRCU 1903 select MMU_NOTIFIER 1904 select NUMA_KEEP_MEMINFO if NUMA 1905 help 1906 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1907 that can be used by applications to set aside private regions of code 1908 and data, referred to as enclaves. An enclave's private memory can 1909 only be accessed by code running within the enclave. Accesses from 1910 outside the enclave, including other enclaves, are disallowed by 1911 hardware. 1912 1913 If unsure, say N. 1914 1915config EFI 1916 bool "EFI runtime service support" 1917 depends on ACPI 1918 select UCS2_STRING 1919 select EFI_RUNTIME_WRAPPERS 1920 help 1921 This enables the kernel to use EFI runtime services that are 1922 available (such as the EFI variable services). 1923 1924 This option is only useful on systems that have EFI firmware. 1925 In addition, you should use the latest ELILO loader available 1926 at <http://elilo.sourceforge.net> in order to take advantage 1927 of EFI runtime services. However, even with this option, the 1928 resultant kernel should continue to boot on existing non-EFI 1929 platforms. 1930 1931config EFI_STUB 1932 bool "EFI stub support" 1933 depends on EFI && !X86_USE_3DNOW 1934 depends on $(cc-option,-mabi=ms) || X86_32 1935 select RELOCATABLE 1936 help 1937 This kernel feature allows a bzImage to be loaded directly 1938 by EFI firmware without the use of a bootloader. 1939 1940 See Documentation/admin-guide/efi-stub.rst for more information. 1941 1942config EFI_MIXED 1943 bool "EFI mixed-mode support" 1944 depends on EFI_STUB && X86_64 1945 help 1946 Enabling this feature allows a 64-bit kernel to be booted 1947 on a 32-bit firmware, provided that your CPU supports 64-bit 1948 mode. 1949 1950 Note that it is not possible to boot a mixed-mode enabled 1951 kernel via the EFI boot stub - a bootloader that supports 1952 the EFI handover protocol must be used. 1953 1954 If unsure, say N. 1955 1956source "kernel/Kconfig.hz" 1957 1958config KEXEC 1959 bool "kexec system call" 1960 select KEXEC_CORE 1961 help 1962 kexec is a system call that implements the ability to shutdown your 1963 current kernel, and to start another kernel. It is like a reboot 1964 but it is independent of the system firmware. And like a reboot 1965 you can start any kernel with it, not just Linux. 1966 1967 The name comes from the similarity to the exec system call. 1968 1969 It is an ongoing process to be certain the hardware in a machine 1970 is properly shutdown, so do not be surprised if this code does not 1971 initially work for you. As of this writing the exact hardware 1972 interface is strongly in flux, so no good recommendation can be 1973 made. 1974 1975config KEXEC_FILE 1976 bool "kexec file based system call" 1977 select KEXEC_CORE 1978 select BUILD_BIN2C 1979 depends on X86_64 1980 depends on CRYPTO=y 1981 depends on CRYPTO_SHA256=y 1982 help 1983 This is new version of kexec system call. This system call is 1984 file based and takes file descriptors as system call argument 1985 for kernel and initramfs as opposed to list of segments as 1986 accepted by previous system call. 1987 1988config ARCH_HAS_KEXEC_PURGATORY 1989 def_bool KEXEC_FILE 1990 1991config KEXEC_SIG 1992 bool "Verify kernel signature during kexec_file_load() syscall" 1993 depends on KEXEC_FILE 1994 help 1995 1996 This option makes the kexec_file_load() syscall check for a valid 1997 signature of the kernel image. The image can still be loaded without 1998 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 1999 there's a signature that we can check, then it must be valid. 2000 2001 In addition to this option, you need to enable signature 2002 verification for the corresponding kernel image type being 2003 loaded in order for this to work. 2004 2005config KEXEC_SIG_FORCE 2006 bool "Require a valid signature in kexec_file_load() syscall" 2007 depends on KEXEC_SIG 2008 help 2009 This option makes kernel signature verification mandatory for 2010 the kexec_file_load() syscall. 2011 2012config KEXEC_BZIMAGE_VERIFY_SIG 2013 bool "Enable bzImage signature verification support" 2014 depends on KEXEC_SIG 2015 depends on SIGNED_PE_FILE_VERIFICATION 2016 select SYSTEM_TRUSTED_KEYRING 2017 help 2018 Enable bzImage signature verification support. 2019 2020config CRASH_DUMP 2021 bool "kernel crash dumps" 2022 depends on X86_64 || (X86_32 && HIGHMEM) 2023 help 2024 Generate crash dump after being started by kexec. 2025 This should be normally only set in special crash dump kernels 2026 which are loaded in the main kernel with kexec-tools into 2027 a specially reserved region and then later executed after 2028 a crash by kdump/kexec. The crash dump kernel must be compiled 2029 to a memory address not used by the main kernel or BIOS using 2030 PHYSICAL_START, or it must be built as a relocatable image 2031 (CONFIG_RELOCATABLE=y). 2032 For more details see Documentation/admin-guide/kdump/kdump.rst 2033 2034config KEXEC_JUMP 2035 bool "kexec jump" 2036 depends on KEXEC && HIBERNATION 2037 help 2038 Jump between original kernel and kexeced kernel and invoke 2039 code in physical address mode via KEXEC 2040 2041config PHYSICAL_START 2042 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2043 default "0x1000000" 2044 help 2045 This gives the physical address where the kernel is loaded. 2046 2047 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2048 bzImage will decompress itself to above physical address and 2049 run from there. Otherwise, bzImage will run from the address where 2050 it has been loaded by the boot loader and will ignore above physical 2051 address. 2052 2053 In normal kdump cases one does not have to set/change this option 2054 as now bzImage can be compiled as a completely relocatable image 2055 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2056 address. This option is mainly useful for the folks who don't want 2057 to use a bzImage for capturing the crash dump and want to use a 2058 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2059 to be specifically compiled to run from a specific memory area 2060 (normally a reserved region) and this option comes handy. 2061 2062 So if you are using bzImage for capturing the crash dump, 2063 leave the value here unchanged to 0x1000000 and set 2064 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2065 for capturing the crash dump change this value to start of 2066 the reserved region. In other words, it can be set based on 2067 the "X" value as specified in the "crashkernel=YM@XM" 2068 command line boot parameter passed to the panic-ed 2069 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2070 for more details about crash dumps. 2071 2072 Usage of bzImage for capturing the crash dump is recommended as 2073 one does not have to build two kernels. Same kernel can be used 2074 as production kernel and capture kernel. Above option should have 2075 gone away after relocatable bzImage support is introduced. But it 2076 is present because there are users out there who continue to use 2077 vmlinux for dump capture. This option should go away down the 2078 line. 2079 2080 Don't change this unless you know what you are doing. 2081 2082config RELOCATABLE 2083 bool "Build a relocatable kernel" 2084 default y 2085 help 2086 This builds a kernel image that retains relocation information 2087 so it can be loaded someplace besides the default 1MB. 2088 The relocations tend to make the kernel binary about 10% larger, 2089 but are discarded at runtime. 2090 2091 One use is for the kexec on panic case where the recovery kernel 2092 must live at a different physical address than the primary 2093 kernel. 2094 2095 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2096 it has been loaded at and the compile time physical address 2097 (CONFIG_PHYSICAL_START) is used as the minimum location. 2098 2099config RANDOMIZE_BASE 2100 bool "Randomize the address of the kernel image (KASLR)" 2101 depends on RELOCATABLE 2102 default y 2103 help 2104 In support of Kernel Address Space Layout Randomization (KASLR), 2105 this randomizes the physical address at which the kernel image 2106 is decompressed and the virtual address where the kernel 2107 image is mapped, as a security feature that deters exploit 2108 attempts relying on knowledge of the location of kernel 2109 code internals. 2110 2111 On 64-bit, the kernel physical and virtual addresses are 2112 randomized separately. The physical address will be anywhere 2113 between 16MB and the top of physical memory (up to 64TB). The 2114 virtual address will be randomized from 16MB up to 1GB (9 bits 2115 of entropy). Note that this also reduces the memory space 2116 available to kernel modules from 1.5GB to 1GB. 2117 2118 On 32-bit, the kernel physical and virtual addresses are 2119 randomized together. They will be randomized from 16MB up to 2120 512MB (8 bits of entropy). 2121 2122 Entropy is generated using the RDRAND instruction if it is 2123 supported. If RDTSC is supported, its value is mixed into 2124 the entropy pool as well. If neither RDRAND nor RDTSC are 2125 supported, then entropy is read from the i8254 timer. The 2126 usable entropy is limited by the kernel being built using 2127 2GB addressing, and that PHYSICAL_ALIGN must be at a 2128 minimum of 2MB. As a result, only 10 bits of entropy are 2129 theoretically possible, but the implementations are further 2130 limited due to memory layouts. 2131 2132 If unsure, say Y. 2133 2134# Relocation on x86 needs some additional build support 2135config X86_NEED_RELOCS 2136 def_bool y 2137 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2138 2139config PHYSICAL_ALIGN 2140 hex "Alignment value to which kernel should be aligned" 2141 default "0x200000" 2142 range 0x2000 0x1000000 if X86_32 2143 range 0x200000 0x1000000 if X86_64 2144 help 2145 This value puts the alignment restrictions on physical address 2146 where kernel is loaded and run from. Kernel is compiled for an 2147 address which meets above alignment restriction. 2148 2149 If bootloader loads the kernel at a non-aligned address and 2150 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2151 address aligned to above value and run from there. 2152 2153 If bootloader loads the kernel at a non-aligned address and 2154 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2155 load address and decompress itself to the address it has been 2156 compiled for and run from there. The address for which kernel is 2157 compiled already meets above alignment restrictions. Hence the 2158 end result is that kernel runs from a physical address meeting 2159 above alignment restrictions. 2160 2161 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2162 this value must be a multiple of 0x200000. 2163 2164 Don't change this unless you know what you are doing. 2165 2166config DYNAMIC_MEMORY_LAYOUT 2167 bool 2168 help 2169 This option makes base addresses of vmalloc and vmemmap as well as 2170 __PAGE_OFFSET movable during boot. 2171 2172config RANDOMIZE_MEMORY 2173 bool "Randomize the kernel memory sections" 2174 depends on X86_64 2175 depends on RANDOMIZE_BASE 2176 select DYNAMIC_MEMORY_LAYOUT 2177 default RANDOMIZE_BASE 2178 help 2179 Randomizes the base virtual address of kernel memory sections 2180 (physical memory mapping, vmalloc & vmemmap). This security feature 2181 makes exploits relying on predictable memory locations less reliable. 2182 2183 The order of allocations remains unchanged. Entropy is generated in 2184 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2185 configuration have in average 30,000 different possible virtual 2186 addresses for each memory section. 2187 2188 If unsure, say Y. 2189 2190config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2191 hex "Physical memory mapping padding" if EXPERT 2192 depends on RANDOMIZE_MEMORY 2193 default "0xa" if MEMORY_HOTPLUG 2194 default "0x0" 2195 range 0x1 0x40 if MEMORY_HOTPLUG 2196 range 0x0 0x40 2197 help 2198 Define the padding in terabytes added to the existing physical 2199 memory size during kernel memory randomization. It is useful 2200 for memory hotplug support but reduces the entropy available for 2201 address randomization. 2202 2203 If unsure, leave at the default value. 2204 2205config HOTPLUG_CPU 2206 def_bool y 2207 depends on SMP 2208 2209config BOOTPARAM_HOTPLUG_CPU0 2210 bool "Set default setting of cpu0_hotpluggable" 2211 depends on HOTPLUG_CPU 2212 help 2213 Set whether default state of cpu0_hotpluggable is on or off. 2214 2215 Say Y here to enable CPU0 hotplug by default. If this switch 2216 is turned on, there is no need to give cpu0_hotplug kernel 2217 parameter and the CPU0 hotplug feature is enabled by default. 2218 2219 Please note: there are two known CPU0 dependencies if you want 2220 to enable the CPU0 hotplug feature either by this switch or by 2221 cpu0_hotplug kernel parameter. 2222 2223 First, resume from hibernate or suspend always starts from CPU0. 2224 So hibernate and suspend are prevented if CPU0 is offline. 2225 2226 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2227 offline if any interrupt can not migrate out of CPU0. There may 2228 be other CPU0 dependencies. 2229 2230 Please make sure the dependencies are under your control before 2231 you enable this feature. 2232 2233 Say N if you don't want to enable CPU0 hotplug feature by default. 2234 You still can enable the CPU0 hotplug feature at boot by kernel 2235 parameter cpu0_hotplug. 2236 2237config DEBUG_HOTPLUG_CPU0 2238 def_bool n 2239 prompt "Debug CPU0 hotplug" 2240 depends on HOTPLUG_CPU 2241 help 2242 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2243 soon as possible and boots up userspace with CPU0 offlined. User 2244 can online CPU0 back after boot time. 2245 2246 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2247 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2248 compilation or giving cpu0_hotplug kernel parameter at boot. 2249 2250 If unsure, say N. 2251 2252config COMPAT_VDSO 2253 def_bool n 2254 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2255 depends on COMPAT_32 2256 help 2257 Certain buggy versions of glibc will crash if they are 2258 presented with a 32-bit vDSO that is not mapped at the address 2259 indicated in its segment table. 2260 2261 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2262 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2263 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2264 the only released version with the bug, but OpenSUSE 9 2265 contains a buggy "glibc 2.3.2". 2266 2267 The symptom of the bug is that everything crashes on startup, saying: 2268 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2269 2270 Saying Y here changes the default value of the vdso32 boot 2271 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2272 This works around the glibc bug but hurts performance. 2273 2274 If unsure, say N: if you are compiling your own kernel, you 2275 are unlikely to be using a buggy version of glibc. 2276 2277choice 2278 prompt "vsyscall table for legacy applications" 2279 depends on X86_64 2280 default LEGACY_VSYSCALL_XONLY 2281 help 2282 Legacy user code that does not know how to find the vDSO expects 2283 to be able to issue three syscalls by calling fixed addresses in 2284 kernel space. Since this location is not randomized with ASLR, 2285 it can be used to assist security vulnerability exploitation. 2286 2287 This setting can be changed at boot time via the kernel command 2288 line parameter vsyscall=[emulate|xonly|none]. 2289 2290 On a system with recent enough glibc (2.14 or newer) and no 2291 static binaries, you can say None without a performance penalty 2292 to improve security. 2293 2294 If unsure, select "Emulate execution only". 2295 2296 config LEGACY_VSYSCALL_EMULATE 2297 bool "Full emulation" 2298 help 2299 The kernel traps and emulates calls into the fixed vsyscall 2300 address mapping. This makes the mapping non-executable, but 2301 it still contains readable known contents, which could be 2302 used in certain rare security vulnerability exploits. This 2303 configuration is recommended when using legacy userspace 2304 that still uses vsyscalls along with legacy binary 2305 instrumentation tools that require code to be readable. 2306 2307 An example of this type of legacy userspace is running 2308 Pin on an old binary that still uses vsyscalls. 2309 2310 config LEGACY_VSYSCALL_XONLY 2311 bool "Emulate execution only" 2312 help 2313 The kernel traps and emulates calls into the fixed vsyscall 2314 address mapping and does not allow reads. This 2315 configuration is recommended when userspace might use the 2316 legacy vsyscall area but support for legacy binary 2317 instrumentation of legacy code is not needed. It mitigates 2318 certain uses of the vsyscall area as an ASLR-bypassing 2319 buffer. 2320 2321 config LEGACY_VSYSCALL_NONE 2322 bool "None" 2323 help 2324 There will be no vsyscall mapping at all. This will 2325 eliminate any risk of ASLR bypass due to the vsyscall 2326 fixed address mapping. Attempts to use the vsyscalls 2327 will be reported to dmesg, so that either old or 2328 malicious userspace programs can be identified. 2329 2330endchoice 2331 2332config CMDLINE_BOOL 2333 bool "Built-in kernel command line" 2334 help 2335 Allow for specifying boot arguments to the kernel at 2336 build time. On some systems (e.g. embedded ones), it is 2337 necessary or convenient to provide some or all of the 2338 kernel boot arguments with the kernel itself (that is, 2339 to not rely on the boot loader to provide them.) 2340 2341 To compile command line arguments into the kernel, 2342 set this option to 'Y', then fill in the 2343 boot arguments in CONFIG_CMDLINE. 2344 2345 Systems with fully functional boot loaders (i.e. non-embedded) 2346 should leave this option set to 'N'. 2347 2348config CMDLINE 2349 string "Built-in kernel command string" 2350 depends on CMDLINE_BOOL 2351 default "" 2352 help 2353 Enter arguments here that should be compiled into the kernel 2354 image and used at boot time. If the boot loader provides a 2355 command line at boot time, it is appended to this string to 2356 form the full kernel command line, when the system boots. 2357 2358 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2359 change this behavior. 2360 2361 In most cases, the command line (whether built-in or provided 2362 by the boot loader) should specify the device for the root 2363 file system. 2364 2365config CMDLINE_OVERRIDE 2366 bool "Built-in command line overrides boot loader arguments" 2367 depends on CMDLINE_BOOL && CMDLINE != "" 2368 help 2369 Set this option to 'Y' to have the kernel ignore the boot loader 2370 command line, and use ONLY the built-in command line. 2371 2372 This is used to work around broken boot loaders. This should 2373 be set to 'N' under normal conditions. 2374 2375config MODIFY_LDT_SYSCALL 2376 bool "Enable the LDT (local descriptor table)" if EXPERT 2377 default y 2378 help 2379 Linux can allow user programs to install a per-process x86 2380 Local Descriptor Table (LDT) using the modify_ldt(2) system 2381 call. This is required to run 16-bit or segmented code such as 2382 DOSEMU or some Wine programs. It is also used by some very old 2383 threading libraries. 2384 2385 Enabling this feature adds a small amount of overhead to 2386 context switches and increases the low-level kernel attack 2387 surface. Disabling it removes the modify_ldt(2) system call. 2388 2389 Saying 'N' here may make sense for embedded or server kernels. 2390 2391source "kernel/livepatch/Kconfig" 2392 2393endmenu 2394 2395config ARCH_HAS_ADD_PAGES 2396 def_bool y 2397 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2398 2399config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2400 def_bool y 2401 2402config USE_PERCPU_NUMA_NODE_ID 2403 def_bool y 2404 depends on NUMA 2405 2406menu "Power management and ACPI options" 2407 2408config ARCH_HIBERNATION_HEADER 2409 def_bool y 2410 depends on HIBERNATION 2411 2412source "kernel/power/Kconfig" 2413 2414source "drivers/acpi/Kconfig" 2415 2416config X86_APM_BOOT 2417 def_bool y 2418 depends on APM 2419 2420menuconfig APM 2421 tristate "APM (Advanced Power Management) BIOS support" 2422 depends on X86_32 && PM_SLEEP 2423 help 2424 APM is a BIOS specification for saving power using several different 2425 techniques. This is mostly useful for battery powered laptops with 2426 APM compliant BIOSes. If you say Y here, the system time will be 2427 reset after a RESUME operation, the /proc/apm device will provide 2428 battery status information, and user-space programs will receive 2429 notification of APM "events" (e.g. battery status change). 2430 2431 If you select "Y" here, you can disable actual use of the APM 2432 BIOS by passing the "apm=off" option to the kernel at boot time. 2433 2434 Note that the APM support is almost completely disabled for 2435 machines with more than one CPU. 2436 2437 In order to use APM, you will need supporting software. For location 2438 and more information, read <file:Documentation/power/apm-acpi.rst> 2439 and the Battery Powered Linux mini-HOWTO, available from 2440 <http://www.tldp.org/docs.html#howto>. 2441 2442 This driver does not spin down disk drives (see the hdparm(8) 2443 manpage ("man 8 hdparm") for that), and it doesn't turn off 2444 VESA-compliant "green" monitors. 2445 2446 This driver does not support the TI 4000M TravelMate and the ACER 2447 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2448 desktop machines also don't have compliant BIOSes, and this driver 2449 may cause those machines to panic during the boot phase. 2450 2451 Generally, if you don't have a battery in your machine, there isn't 2452 much point in using this driver and you should say N. If you get 2453 random kernel OOPSes or reboots that don't seem to be related to 2454 anything, try disabling/enabling this option (or disabling/enabling 2455 APM in your BIOS). 2456 2457 Some other things you should try when experiencing seemingly random, 2458 "weird" problems: 2459 2460 1) make sure that you have enough swap space and that it is 2461 enabled. 2462 2) pass the "no-hlt" option to the kernel 2463 3) switch on floating point emulation in the kernel and pass 2464 the "no387" option to the kernel 2465 4) pass the "floppy=nodma" option to the kernel 2466 5) pass the "mem=4M" option to the kernel (thereby disabling 2467 all but the first 4 MB of RAM) 2468 6) make sure that the CPU is not over clocked. 2469 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2470 8) disable the cache from your BIOS settings 2471 9) install a fan for the video card or exchange video RAM 2472 10) install a better fan for the CPU 2473 11) exchange RAM chips 2474 12) exchange the motherboard. 2475 2476 To compile this driver as a module, choose M here: the 2477 module will be called apm. 2478 2479if APM 2480 2481config APM_IGNORE_USER_SUSPEND 2482 bool "Ignore USER SUSPEND" 2483 help 2484 This option will ignore USER SUSPEND requests. On machines with a 2485 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2486 series notebooks, it is necessary to say Y because of a BIOS bug. 2487 2488config APM_DO_ENABLE 2489 bool "Enable PM at boot time" 2490 help 2491 Enable APM features at boot time. From page 36 of the APM BIOS 2492 specification: "When disabled, the APM BIOS does not automatically 2493 power manage devices, enter the Standby State, enter the Suspend 2494 State, or take power saving steps in response to CPU Idle calls." 2495 This driver will make CPU Idle calls when Linux is idle (unless this 2496 feature is turned off -- see "Do CPU IDLE calls", below). This 2497 should always save battery power, but more complicated APM features 2498 will be dependent on your BIOS implementation. You may need to turn 2499 this option off if your computer hangs at boot time when using APM 2500 support, or if it beeps continuously instead of suspending. Turn 2501 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2502 T400CDT. This is off by default since most machines do fine without 2503 this feature. 2504 2505config APM_CPU_IDLE 2506 depends on CPU_IDLE 2507 bool "Make CPU Idle calls when idle" 2508 help 2509 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2510 On some machines, this can activate improved power savings, such as 2511 a slowed CPU clock rate, when the machine is idle. These idle calls 2512 are made after the idle loop has run for some length of time (e.g., 2513 333 mS). On some machines, this will cause a hang at boot time or 2514 whenever the CPU becomes idle. (On machines with more than one CPU, 2515 this option does nothing.) 2516 2517config APM_DISPLAY_BLANK 2518 bool "Enable console blanking using APM" 2519 help 2520 Enable console blanking using the APM. Some laptops can use this to 2521 turn off the LCD backlight when the screen blanker of the Linux 2522 virtual console blanks the screen. Note that this is only used by 2523 the virtual console screen blanker, and won't turn off the backlight 2524 when using the X Window system. This also doesn't have anything to 2525 do with your VESA-compliant power-saving monitor. Further, this 2526 option doesn't work for all laptops -- it might not turn off your 2527 backlight at all, or it might print a lot of errors to the console, 2528 especially if you are using gpm. 2529 2530config APM_ALLOW_INTS 2531 bool "Allow interrupts during APM BIOS calls" 2532 help 2533 Normally we disable external interrupts while we are making calls to 2534 the APM BIOS as a measure to lessen the effects of a badly behaving 2535 BIOS implementation. The BIOS should reenable interrupts if it 2536 needs to. Unfortunately, some BIOSes do not -- especially those in 2537 many of the newer IBM Thinkpads. If you experience hangs when you 2538 suspend, try setting this to Y. Otherwise, say N. 2539 2540endif # APM 2541 2542source "drivers/cpufreq/Kconfig" 2543 2544source "drivers/cpuidle/Kconfig" 2545 2546source "drivers/idle/Kconfig" 2547 2548endmenu 2549 2550 2551menu "Bus options (PCI etc.)" 2552 2553choice 2554 prompt "PCI access mode" 2555 depends on X86_32 && PCI 2556 default PCI_GOANY 2557 help 2558 On PCI systems, the BIOS can be used to detect the PCI devices and 2559 determine their configuration. However, some old PCI motherboards 2560 have BIOS bugs and may crash if this is done. Also, some embedded 2561 PCI-based systems don't have any BIOS at all. Linux can also try to 2562 detect the PCI hardware directly without using the BIOS. 2563 2564 With this option, you can specify how Linux should detect the 2565 PCI devices. If you choose "BIOS", the BIOS will be used, 2566 if you choose "Direct", the BIOS won't be used, and if you 2567 choose "MMConfig", then PCI Express MMCONFIG will be used. 2568 If you choose "Any", the kernel will try MMCONFIG, then the 2569 direct access method and falls back to the BIOS if that doesn't 2570 work. If unsure, go with the default, which is "Any". 2571 2572config PCI_GOBIOS 2573 bool "BIOS" 2574 2575config PCI_GOMMCONFIG 2576 bool "MMConfig" 2577 2578config PCI_GODIRECT 2579 bool "Direct" 2580 2581config PCI_GOOLPC 2582 bool "OLPC XO-1" 2583 depends on OLPC 2584 2585config PCI_GOANY 2586 bool "Any" 2587 2588endchoice 2589 2590config PCI_BIOS 2591 def_bool y 2592 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2593 2594# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2595config PCI_DIRECT 2596 def_bool y 2597 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2598 2599config PCI_MMCONFIG 2600 bool "Support mmconfig PCI config space access" if X86_64 2601 default y 2602 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2603 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2604 2605config PCI_OLPC 2606 def_bool y 2607 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2608 2609config PCI_XEN 2610 def_bool y 2611 depends on PCI && XEN 2612 2613config MMCONF_FAM10H 2614 def_bool y 2615 depends on X86_64 && PCI_MMCONFIG && ACPI 2616 2617config PCI_CNB20LE_QUIRK 2618 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2619 depends on PCI 2620 help 2621 Read the PCI windows out of the CNB20LE host bridge. This allows 2622 PCI hotplug to work on systems with the CNB20LE chipset which do 2623 not have ACPI. 2624 2625 There's no public spec for this chipset, and this functionality 2626 is known to be incomplete. 2627 2628 You should say N unless you know you need this. 2629 2630config ISA_BUS 2631 bool "ISA bus support on modern systems" if EXPERT 2632 help 2633 Expose ISA bus device drivers and options available for selection and 2634 configuration. Enable this option if your target machine has an ISA 2635 bus. ISA is an older system, displaced by PCI and newer bus 2636 architectures -- if your target machine is modern, it probably does 2637 not have an ISA bus. 2638 2639 If unsure, say N. 2640 2641# x86_64 have no ISA slots, but can have ISA-style DMA. 2642config ISA_DMA_API 2643 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2644 default y 2645 help 2646 Enables ISA-style DMA support for devices requiring such controllers. 2647 If unsure, say Y. 2648 2649if X86_32 2650 2651config ISA 2652 bool "ISA support" 2653 help 2654 Find out whether you have ISA slots on your motherboard. ISA is the 2655 name of a bus system, i.e. the way the CPU talks to the other stuff 2656 inside your box. Other bus systems are PCI, EISA, MicroChannel 2657 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2658 newer boards don't support it. If you have ISA, say Y, otherwise N. 2659 2660config SCx200 2661 tristate "NatSemi SCx200 support" 2662 help 2663 This provides basic support for National Semiconductor's 2664 (now AMD's) Geode processors. The driver probes for the 2665 PCI-IDs of several on-chip devices, so its a good dependency 2666 for other scx200_* drivers. 2667 2668 If compiled as a module, the driver is named scx200. 2669 2670config SCx200HR_TIMER 2671 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2672 depends on SCx200 2673 default y 2674 help 2675 This driver provides a clocksource built upon the on-chip 2676 27MHz high-resolution timer. Its also a workaround for 2677 NSC Geode SC-1100's buggy TSC, which loses time when the 2678 processor goes idle (as is done by the scheduler). The 2679 other workaround is idle=poll boot option. 2680 2681config OLPC 2682 bool "One Laptop Per Child support" 2683 depends on !X86_PAE 2684 select GPIOLIB 2685 select OF 2686 select OF_PROMTREE 2687 select IRQ_DOMAIN 2688 select OLPC_EC 2689 help 2690 Add support for detecting the unique features of the OLPC 2691 XO hardware. 2692 2693config OLPC_XO1_PM 2694 bool "OLPC XO-1 Power Management" 2695 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2696 help 2697 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2698 2699config OLPC_XO1_RTC 2700 bool "OLPC XO-1 Real Time Clock" 2701 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2702 help 2703 Add support for the XO-1 real time clock, which can be used as a 2704 programmable wakeup source. 2705 2706config OLPC_XO1_SCI 2707 bool "OLPC XO-1 SCI extras" 2708 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2709 depends on INPUT=y 2710 select POWER_SUPPLY 2711 help 2712 Add support for SCI-based features of the OLPC XO-1 laptop: 2713 - EC-driven system wakeups 2714 - Power button 2715 - Ebook switch 2716 - Lid switch 2717 - AC adapter status updates 2718 - Battery status updates 2719 2720config OLPC_XO15_SCI 2721 bool "OLPC XO-1.5 SCI extras" 2722 depends on OLPC && ACPI 2723 select POWER_SUPPLY 2724 help 2725 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2726 - EC-driven system wakeups 2727 - AC adapter status updates 2728 - Battery status updates 2729 2730config ALIX 2731 bool "PCEngines ALIX System Support (LED setup)" 2732 select GPIOLIB 2733 help 2734 This option enables system support for the PCEngines ALIX. 2735 At present this just sets up LEDs for GPIO control on 2736 ALIX2/3/6 boards. However, other system specific setup should 2737 get added here. 2738 2739 Note: You must still enable the drivers for GPIO and LED support 2740 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2741 2742 Note: You have to set alix.force=1 for boards with Award BIOS. 2743 2744config NET5501 2745 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2746 select GPIOLIB 2747 help 2748 This option enables system support for the Soekris Engineering net5501. 2749 2750config GEOS 2751 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2752 select GPIOLIB 2753 depends on DMI 2754 help 2755 This option enables system support for the Traverse Technologies GEOS. 2756 2757config TS5500 2758 bool "Technologic Systems TS-5500 platform support" 2759 depends on MELAN 2760 select CHECK_SIGNATURE 2761 select NEW_LEDS 2762 select LEDS_CLASS 2763 help 2764 This option enables system support for the Technologic Systems TS-5500. 2765 2766endif # X86_32 2767 2768config AMD_NB 2769 def_bool y 2770 depends on CPU_SUP_AMD && PCI 2771 2772endmenu 2773 2774 2775menu "Binary Emulations" 2776 2777config IA32_EMULATION 2778 bool "IA32 Emulation" 2779 depends on X86_64 2780 select ARCH_WANT_OLD_COMPAT_IPC 2781 select BINFMT_ELF 2782 select COMPAT_OLD_SIGACTION 2783 help 2784 Include code to run legacy 32-bit programs under a 2785 64-bit kernel. You should likely turn this on, unless you're 2786 100% sure that you don't have any 32-bit programs left. 2787 2788config IA32_AOUT 2789 tristate "IA32 a.out support" 2790 depends on IA32_EMULATION 2791 depends on BROKEN 2792 help 2793 Support old a.out binaries in the 32bit emulation. 2794 2795config X86_X32 2796 bool "x32 ABI for 64-bit mode" 2797 depends on X86_64 2798 help 2799 Include code to run binaries for the x32 native 32-bit ABI 2800 for 64-bit processors. An x32 process gets access to the 2801 full 64-bit register file and wide data path while leaving 2802 pointers at 32 bits for smaller memory footprint. 2803 2804 You will need a recent binutils (2.22 or later) with 2805 elf32_x86_64 support enabled to compile a kernel with this 2806 option set. 2807 2808config COMPAT_32 2809 def_bool y 2810 depends on IA32_EMULATION || X86_32 2811 select HAVE_UID16 2812 select OLD_SIGSUSPEND3 2813 2814config COMPAT 2815 def_bool y 2816 depends on IA32_EMULATION || X86_X32 2817 2818if COMPAT 2819config COMPAT_FOR_U64_ALIGNMENT 2820 def_bool y 2821 2822config SYSVIPC_COMPAT 2823 def_bool y 2824 depends on SYSVIPC 2825endif 2826 2827endmenu 2828 2829 2830config HAVE_ATOMIC_IOMAP 2831 def_bool y 2832 depends on X86_32 2833 2834source "arch/x86/kvm/Kconfig" 2835 2836source "arch/x86/Kconfig.assembler" 2837