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 if X86_64 109 select ARCH_SUPPORTS_LTO_CLANG_THIN if X86_64 110 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_WANT_HUGE_PMD_SHARE 119 select ARCH_WANT_LD_ORPHAN_WARN 120 select ARCH_WANTS_THP_SWAP if X86_64 121 select BUILDTIME_TABLE_SORT 122 select CLKEVT_I8253 123 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 124 select CLOCKSOURCE_WATCHDOG 125 select DCACHE_WORD_ACCESS 126 select EDAC_ATOMIC_SCRUB 127 select EDAC_SUPPORT 128 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 129 select GENERIC_CLOCKEVENTS_MIN_ADJUST 130 select GENERIC_CMOS_UPDATE 131 select GENERIC_CPU_AUTOPROBE 132 select GENERIC_CPU_VULNERABILITIES 133 select GENERIC_EARLY_IOREMAP 134 select GENERIC_ENTRY 135 select GENERIC_FIND_FIRST_BIT 136 select GENERIC_IOMAP 137 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 138 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 139 select GENERIC_IRQ_MIGRATION if SMP 140 select GENERIC_IRQ_PROBE 141 select GENERIC_IRQ_RESERVATION_MODE 142 select GENERIC_IRQ_SHOW 143 select GENERIC_PENDING_IRQ if SMP 144 select GENERIC_PTDUMP 145 select GENERIC_SMP_IDLE_THREAD 146 select GENERIC_STRNCPY_FROM_USER 147 select GENERIC_STRNLEN_USER 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_IDE 205 select HAVE_IOREMAP_PROT 206 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 207 select HAVE_IRQ_TIME_ACCOUNTING 208 select HAVE_KERNEL_BZIP2 209 select HAVE_KERNEL_GZIP 210 select HAVE_KERNEL_LZ4 211 select HAVE_KERNEL_LZMA 212 select HAVE_KERNEL_LZO 213 select HAVE_KERNEL_XZ 214 select HAVE_KERNEL_ZSTD 215 select HAVE_KPROBES 216 select HAVE_KPROBES_ON_FTRACE 217 select HAVE_FUNCTION_ERROR_INJECTION 218 select HAVE_KRETPROBES 219 select HAVE_KVM 220 select HAVE_LIVEPATCH if X86_64 221 select HAVE_MIXED_BREAKPOINTS_REGS 222 select HAVE_MOD_ARCH_SPECIFIC 223 select HAVE_MOVE_PMD 224 select HAVE_MOVE_PUD 225 select HAVE_NMI 226 select HAVE_OPTPROBES 227 select HAVE_PCSPKR_PLATFORM 228 select HAVE_PERF_EVENTS 229 select HAVE_PERF_EVENTS_NMI 230 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 231 select HAVE_PCI 232 select HAVE_PERF_REGS 233 select HAVE_PERF_USER_STACK_DUMP 234 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 235 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 236 select HAVE_REGS_AND_STACK_ACCESS_API 237 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 238 select HAVE_FUNCTION_ARG_ACCESS_API 239 select HAVE_SOFTIRQ_ON_OWN_STACK 240 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 241 select HAVE_STACK_VALIDATION if X86_64 242 select HAVE_STATIC_CALL 243 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 244 select HAVE_PREEMPT_DYNAMIC 245 select HAVE_RSEQ 246 select HAVE_SYSCALL_TRACEPOINTS 247 select HAVE_UNSTABLE_SCHED_CLOCK 248 select HAVE_USER_RETURN_NOTIFIER 249 select HAVE_GENERIC_VDSO 250 select HOTPLUG_SMT if SMP 251 select IRQ_FORCED_THREADING 252 select NEED_SG_DMA_LENGTH 253 select PCI_DOMAINS if PCI 254 select PCI_LOCKLESS_CONFIG if PCI 255 select PERF_EVENTS 256 select RTC_LIB 257 select RTC_MC146818_LIB 258 select SPARSE_IRQ 259 select SRCU 260 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 261 select SYSCTL_EXCEPTION_TRACE 262 select THREAD_INFO_IN_TASK 263 select 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_SUSPEND_POSSIBLE 343 def_bool y 344 345config ARCH_WANT_GENERAL_HUGETLB 346 def_bool y 347 348config AUDIT_ARCH 349 def_bool y if X86_64 350 351config KASAN_SHADOW_OFFSET 352 hex 353 depends on KASAN 354 default 0xdffffc0000000000 355 356config HAVE_INTEL_TXT 357 def_bool y 358 depends on INTEL_IOMMU && ACPI 359 360config X86_32_SMP 361 def_bool y 362 depends on X86_32 && SMP 363 364config X86_64_SMP 365 def_bool y 366 depends on X86_64 && SMP 367 368config ARCH_SUPPORTS_UPROBES 369 def_bool y 370 371config FIX_EARLYCON_MEM 372 def_bool y 373 374config DYNAMIC_PHYSICAL_MASK 375 bool 376 377config PGTABLE_LEVELS 378 int 379 default 5 if X86_5LEVEL 380 default 4 if X86_64 381 default 3 if X86_PAE 382 default 2 383 384config CC_HAS_SANE_STACKPROTECTOR 385 bool 386 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 387 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 388 help 389 We have to make sure stack protector is unconditionally disabled if 390 the compiler produces broken code or if it does not let us control 391 the segment on 32-bit kernels. 392 393menu "Processor type and features" 394 395config SMP 396 bool "Symmetric multi-processing support" 397 help 398 This enables support for systems with more than one CPU. If you have 399 a system with only one CPU, say N. If you have a system with more 400 than one CPU, say Y. 401 402 If you say N here, the kernel will run on uni- and multiprocessor 403 machines, but will use only one CPU of a multiprocessor machine. If 404 you say Y here, the kernel will run on many, but not all, 405 uniprocessor machines. On a uniprocessor machine, the kernel 406 will run faster if you say N here. 407 408 Note that if you say Y here and choose architecture "586" or 409 "Pentium" under "Processor family", the kernel will not work on 486 410 architectures. Similarly, multiprocessor kernels for the "PPro" 411 architecture may not work on all Pentium based boards. 412 413 People using multiprocessor machines who say Y here should also say 414 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 415 Management" code will be disabled if you say Y here. 416 417 See also <file:Documentation/x86/i386/IO-APIC.rst>, 418 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 419 <http://www.tldp.org/docs.html#howto>. 420 421 If you don't know what to do here, say N. 422 423config X86_FEATURE_NAMES 424 bool "Processor feature human-readable names" if EMBEDDED 425 default y 426 help 427 This option compiles in a table of x86 feature bits and corresponding 428 names. This is required to support /proc/cpuinfo and a few kernel 429 messages. You can disable this to save space, at the expense of 430 making those few kernel messages show numeric feature bits instead. 431 432 If in doubt, say Y. 433 434config X86_X2APIC 435 bool "Support x2apic" 436 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 437 help 438 This enables x2apic support on CPUs that have this feature. 439 440 This allows 32-bit apic IDs (so it can support very large systems), 441 and accesses the local apic via MSRs not via mmio. 442 443 If you don't know what to do here, say N. 444 445config X86_MPPARSE 446 bool "Enable MPS table" if ACPI 447 default y 448 depends on X86_LOCAL_APIC 449 help 450 For old smp systems that do not have proper acpi support. Newer systems 451 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 452 453config GOLDFISH 454 def_bool y 455 depends on X86_GOLDFISH 456 457config RETPOLINE 458 bool "Avoid speculative indirect branches in kernel" 459 default y 460 help 461 Compile kernel with the retpoline compiler options to guard against 462 kernel-to-user data leaks by avoiding speculative indirect 463 branches. Requires a compiler with -mindirect-branch=thunk-extern 464 support for full protection. The kernel may run slower. 465 466config X86_CPU_RESCTRL 467 bool "x86 CPU resource control support" 468 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 469 select KERNFS 470 select PROC_CPU_RESCTRL if PROC_FS 471 help 472 Enable x86 CPU resource control support. 473 474 Provide support for the allocation and monitoring of system resources 475 usage by the CPU. 476 477 Intel calls this Intel Resource Director Technology 478 (Intel(R) RDT). More information about RDT can be found in the 479 Intel x86 Architecture Software Developer Manual. 480 481 AMD calls this AMD Platform Quality of Service (AMD QoS). 482 More information about AMD QoS can be found in the AMD64 Technology 483 Platform Quality of Service Extensions manual. 484 485 Say N if unsure. 486 487if X86_32 488config X86_BIGSMP 489 bool "Support for big SMP systems with more than 8 CPUs" 490 depends on SMP 491 help 492 This option is needed for the systems that have more than 8 CPUs. 493 494config X86_EXTENDED_PLATFORM 495 bool "Support for extended (non-PC) x86 platforms" 496 default y 497 help 498 If you disable this option then the kernel will only support 499 standard PC platforms. (which covers the vast majority of 500 systems out there.) 501 502 If you enable this option then you'll be able to select support 503 for the following (non-PC) 32 bit x86 platforms: 504 Goldfish (Android emulator) 505 AMD Elan 506 RDC R-321x SoC 507 SGI 320/540 (Visual Workstation) 508 STA2X11-based (e.g. Northville) 509 Moorestown MID devices 510 511 If you have one of these systems, or if you want to build a 512 generic distribution kernel, say Y here - otherwise say N. 513endif 514 515if X86_64 516config X86_EXTENDED_PLATFORM 517 bool "Support for extended (non-PC) x86 platforms" 518 default y 519 help 520 If you disable this option then the kernel will only support 521 standard PC platforms. (which covers the vast majority of 522 systems out there.) 523 524 If you enable this option then you'll be able to select support 525 for the following (non-PC) 64 bit x86 platforms: 526 Numascale NumaChip 527 ScaleMP vSMP 528 SGI Ultraviolet 529 530 If you have one of these systems, or if you want to build a 531 generic distribution kernel, say Y here - otherwise say N. 532endif 533# This is an alphabetically sorted list of 64 bit extended platforms 534# Please maintain the alphabetic order if and when there are additions 535config X86_NUMACHIP 536 bool "Numascale NumaChip" 537 depends on X86_64 538 depends on X86_EXTENDED_PLATFORM 539 depends on NUMA 540 depends on SMP 541 depends on X86_X2APIC 542 depends on PCI_MMCONFIG 543 help 544 Adds support for Numascale NumaChip large-SMP systems. Needed to 545 enable more than ~168 cores. 546 If you don't have one of these, you should say N here. 547 548config X86_VSMP 549 bool "ScaleMP vSMP" 550 select HYPERVISOR_GUEST 551 select PARAVIRT 552 depends on X86_64 && PCI 553 depends on X86_EXTENDED_PLATFORM 554 depends on SMP 555 help 556 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 557 supposed to run on these EM64T-based machines. Only choose this option 558 if you have one of these machines. 559 560config X86_UV 561 bool "SGI Ultraviolet" 562 depends on X86_64 563 depends on X86_EXTENDED_PLATFORM 564 depends on NUMA 565 depends on EFI 566 depends on KEXEC_CORE 567 depends on X86_X2APIC 568 depends on PCI 569 help 570 This option is needed in order to support SGI Ultraviolet systems. 571 If you don't have one of these, you should say N here. 572 573# Following is an alphabetically sorted list of 32 bit extended platforms 574# Please maintain the alphabetic order if and when there are additions 575 576config X86_GOLDFISH 577 bool "Goldfish (Virtual Platform)" 578 depends on X86_EXTENDED_PLATFORM 579 help 580 Enable support for the Goldfish virtual platform used primarily 581 for Android development. Unless you are building for the Android 582 Goldfish emulator say N here. 583 584config X86_INTEL_CE 585 bool "CE4100 TV platform" 586 depends on PCI 587 depends on PCI_GODIRECT 588 depends on X86_IO_APIC 589 depends on X86_32 590 depends on X86_EXTENDED_PLATFORM 591 select X86_REBOOTFIXUPS 592 select OF 593 select OF_EARLY_FLATTREE 594 help 595 Select for the Intel CE media processor (CE4100) SOC. 596 This option compiles in support for the CE4100 SOC for settop 597 boxes and media devices. 598 599config X86_INTEL_MID 600 bool "Intel MID platform support" 601 depends on X86_EXTENDED_PLATFORM 602 depends on X86_PLATFORM_DEVICES 603 depends on PCI 604 depends on X86_64 || (PCI_GOANY && X86_32) 605 depends on X86_IO_APIC 606 select I2C 607 select DW_APB_TIMER 608 select APB_TIMER 609 select INTEL_SCU_PCI 610 select MFD_INTEL_MSIC 611 help 612 Select to build a kernel capable of supporting Intel MID (Mobile 613 Internet Device) platform systems which do not have the PCI legacy 614 interfaces. If you are building for a PC class system say N here. 615 616 Intel MID platforms are based on an Intel processor and chipset which 617 consume less power than most of the x86 derivatives. 618 619config X86_INTEL_QUARK 620 bool "Intel Quark platform support" 621 depends on X86_32 622 depends on X86_EXTENDED_PLATFORM 623 depends on X86_PLATFORM_DEVICES 624 depends on X86_TSC 625 depends on PCI 626 depends on PCI_GOANY 627 depends on X86_IO_APIC 628 select IOSF_MBI 629 select INTEL_IMR 630 select COMMON_CLK 631 help 632 Select to include support for Quark X1000 SoC. 633 Say Y here if you have a Quark based system such as the Arduino 634 compatible Intel Galileo. 635 636config X86_INTEL_LPSS 637 bool "Intel Low Power Subsystem Support" 638 depends on X86 && ACPI && PCI 639 select COMMON_CLK 640 select PINCTRL 641 select IOSF_MBI 642 help 643 Select to build support for Intel Low Power Subsystem such as 644 found on Intel Lynxpoint PCH. Selecting this option enables 645 things like clock tree (common clock framework) and pincontrol 646 which are needed by the LPSS peripheral drivers. 647 648config X86_AMD_PLATFORM_DEVICE 649 bool "AMD ACPI2Platform devices support" 650 depends on ACPI 651 select COMMON_CLK 652 select PINCTRL 653 help 654 Select to interpret AMD specific ACPI device to platform device 655 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 656 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 657 implemented under PINCTRL subsystem. 658 659config IOSF_MBI 660 tristate "Intel SoC IOSF Sideband support for SoC platforms" 661 depends on PCI 662 help 663 This option enables sideband register access support for Intel SoC 664 platforms. On these platforms the IOSF sideband is used in lieu of 665 MSR's for some register accesses, mostly but not limited to thermal 666 and power. Drivers may query the availability of this device to 667 determine if they need the sideband in order to work on these 668 platforms. The sideband is available on the following SoC products. 669 This list is not meant to be exclusive. 670 - BayTrail 671 - Braswell 672 - Quark 673 674 You should say Y if you are running a kernel on one of these SoC's. 675 676config IOSF_MBI_DEBUG 677 bool "Enable IOSF sideband access through debugfs" 678 depends on IOSF_MBI && DEBUG_FS 679 help 680 Select this option to expose the IOSF sideband access registers (MCR, 681 MDR, MCRX) through debugfs to write and read register information from 682 different units on the SoC. This is most useful for obtaining device 683 state information for debug and analysis. As this is a general access 684 mechanism, users of this option would have specific knowledge of the 685 device they want to access. 686 687 If you don't require the option or are in doubt, say N. 688 689config X86_RDC321X 690 bool "RDC R-321x SoC" 691 depends on X86_32 692 depends on X86_EXTENDED_PLATFORM 693 select M486 694 select X86_REBOOTFIXUPS 695 help 696 This option is needed for RDC R-321x system-on-chip, also known 697 as R-8610-(G). 698 If you don't have one of these chips, you should say N here. 699 700config X86_32_NON_STANDARD 701 bool "Support non-standard 32-bit SMP architectures" 702 depends on X86_32 && SMP 703 depends on X86_EXTENDED_PLATFORM 704 help 705 This option compiles in the bigsmp and STA2X11 default 706 subarchitectures. It is intended for a generic binary 707 kernel. If you select them all, kernel will probe it one by 708 one and will fallback to default. 709 710# Alphabetically sorted list of Non standard 32 bit platforms 711 712config X86_SUPPORTS_MEMORY_FAILURE 713 def_bool y 714 # MCE code calls memory_failure(): 715 depends on X86_MCE 716 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 717 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 718 depends on X86_64 || !SPARSEMEM 719 select ARCH_SUPPORTS_MEMORY_FAILURE 720 721config STA2X11 722 bool "STA2X11 Companion Chip Support" 723 depends on X86_32_NON_STANDARD && PCI 724 select SWIOTLB 725 select MFD_STA2X11 726 select GPIOLIB 727 help 728 This adds support for boards based on the STA2X11 IO-Hub, 729 a.k.a. "ConneXt". The chip is used in place of the standard 730 PC chipset, so all "standard" peripherals are missing. If this 731 option is selected the kernel will still be able to boot on 732 standard PC machines. 733 734config X86_32_IRIS 735 tristate "Eurobraille/Iris poweroff module" 736 depends on X86_32 737 help 738 The Iris machines from EuroBraille do not have APM or ACPI support 739 to shut themselves down properly. A special I/O sequence is 740 needed to do so, which is what this module does at 741 kernel shutdown. 742 743 This is only for Iris machines from EuroBraille. 744 745 If unused, say N. 746 747config SCHED_OMIT_FRAME_POINTER 748 def_bool y 749 prompt "Single-depth WCHAN output" 750 depends on X86 751 help 752 Calculate simpler /proc/<PID>/wchan values. If this option 753 is disabled then wchan values will recurse back to the 754 caller function. This provides more accurate wchan values, 755 at the expense of slightly more scheduling overhead. 756 757 If in doubt, say "Y". 758 759menuconfig HYPERVISOR_GUEST 760 bool "Linux guest support" 761 help 762 Say Y here to enable options for running Linux under various hyper- 763 visors. This option enables basic hypervisor detection and platform 764 setup. 765 766 If you say N, all options in this submenu will be skipped and 767 disabled, and Linux guest support won't be built in. 768 769if HYPERVISOR_GUEST 770 771config PARAVIRT 772 bool "Enable paravirtualization code" 773 depends on HAVE_STATIC_CALL 774 help 775 This changes the kernel so it can modify itself when it is run 776 under a hypervisor, potentially improving performance significantly 777 over full virtualization. However, when run without a hypervisor 778 the kernel is theoretically slower and slightly larger. 779 780config PARAVIRT_XXL 781 bool 782 783config PARAVIRT_DEBUG 784 bool "paravirt-ops debugging" 785 depends on PARAVIRT && DEBUG_KERNEL 786 help 787 Enable to debug paravirt_ops internals. Specifically, BUG if 788 a paravirt_op is missing when it is called. 789 790config PARAVIRT_SPINLOCKS 791 bool "Paravirtualization layer for spinlocks" 792 depends on PARAVIRT && SMP 793 help 794 Paravirtualized spinlocks allow a pvops backend to replace the 795 spinlock implementation with something virtualization-friendly 796 (for example, block the virtual CPU rather than spinning). 797 798 It has a minimal impact on native kernels and gives a nice performance 799 benefit on paravirtualized KVM / Xen kernels. 800 801 If you are unsure how to answer this question, answer Y. 802 803config X86_HV_CALLBACK_VECTOR 804 def_bool n 805 806source "arch/x86/xen/Kconfig" 807 808config KVM_GUEST 809 bool "KVM Guest support (including kvmclock)" 810 depends on PARAVIRT 811 select PARAVIRT_CLOCK 812 select ARCH_CPUIDLE_HALTPOLL 813 select X86_HV_CALLBACK_VECTOR 814 default y 815 help 816 This option enables various optimizations for running under the KVM 817 hypervisor. It includes a paravirtualized clock, so that instead 818 of relying on a PIT (or probably other) emulation by the 819 underlying device model, the host provides the guest with 820 timing infrastructure such as time of day, and system time 821 822config ARCH_CPUIDLE_HALTPOLL 823 def_bool n 824 prompt "Disable host haltpoll when loading haltpoll driver" 825 help 826 If virtualized under KVM, disable host haltpoll. 827 828config PVH 829 bool "Support for running PVH guests" 830 help 831 This option enables the PVH entry point for guest virtual machines 832 as specified in the x86/HVM direct boot ABI. 833 834config PARAVIRT_TIME_ACCOUNTING 835 bool "Paravirtual steal time accounting" 836 depends on PARAVIRT 837 help 838 Select this option to enable fine granularity task steal time 839 accounting. Time spent executing other tasks in parallel with 840 the current vCPU is discounted from the vCPU power. To account for 841 that, there can be a small performance impact. 842 843 If in doubt, say N here. 844 845config PARAVIRT_CLOCK 846 bool 847 848config JAILHOUSE_GUEST 849 bool "Jailhouse non-root cell support" 850 depends on X86_64 && PCI 851 select X86_PM_TIMER 852 help 853 This option allows to run Linux as guest in a Jailhouse non-root 854 cell. You can leave this option disabled if you only want to start 855 Jailhouse and run Linux afterwards in the root cell. 856 857config ACRN_GUEST 858 bool "ACRN Guest support" 859 depends on X86_64 860 select X86_HV_CALLBACK_VECTOR 861 help 862 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 863 a flexible, lightweight reference open-source hypervisor, built with 864 real-time and safety-criticality in mind. It is built for embedded 865 IOT with small footprint and real-time features. More details can be 866 found in https://projectacrn.org/. 867 868endif #HYPERVISOR_GUEST 869 870source "arch/x86/Kconfig.cpu" 871 872config HPET_TIMER 873 def_bool X86_64 874 prompt "HPET Timer Support" if X86_32 875 help 876 Use the IA-PC HPET (High Precision Event Timer) to manage 877 time in preference to the PIT and RTC, if a HPET is 878 present. 879 HPET is the next generation timer replacing legacy 8254s. 880 The HPET provides a stable time base on SMP 881 systems, unlike the TSC, but it is more expensive to access, 882 as it is off-chip. The interface used is documented 883 in the HPET spec, revision 1. 884 885 You can safely choose Y here. However, HPET will only be 886 activated if the platform and the BIOS support this feature. 887 Otherwise the 8254 will be used for timing services. 888 889 Choose N to continue using the legacy 8254 timer. 890 891config HPET_EMULATE_RTC 892 def_bool y 893 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 894 895# Mark as expert because too many people got it wrong. 896# The code disables itself when not needed. 897config DMI 898 default y 899 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 900 bool "Enable DMI scanning" if EXPERT 901 help 902 Enabled scanning of DMI to identify machine quirks. Say Y 903 here unless you have verified that your setup is not 904 affected by entries in the DMI blacklist. Required by PNP 905 BIOS code. 906 907config GART_IOMMU 908 bool "Old AMD GART IOMMU support" 909 select DMA_OPS 910 select IOMMU_HELPER 911 select SWIOTLB 912 depends on X86_64 && PCI && AMD_NB 913 help 914 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 915 GART based hardware IOMMUs. 916 917 The GART supports full DMA access for devices with 32-bit access 918 limitations, on systems with more than 3 GB. This is usually needed 919 for USB, sound, many IDE/SATA chipsets and some other devices. 920 921 Newer systems typically have a modern AMD IOMMU, supported via 922 the CONFIG_AMD_IOMMU=y config option. 923 924 In normal configurations this driver is only active when needed: 925 there's more than 3 GB of memory and the system contains a 926 32-bit limited device. 927 928 If unsure, say Y. 929 930config MAXSMP 931 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 932 depends on X86_64 && SMP && DEBUG_KERNEL 933 select CPUMASK_OFFSTACK 934 help 935 Enable maximum number of CPUS and NUMA Nodes for this architecture. 936 If unsure, say N. 937 938# 939# The maximum number of CPUs supported: 940# 941# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 942# and which can be configured interactively in the 943# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 944# 945# The ranges are different on 32-bit and 64-bit kernels, depending on 946# hardware capabilities and scalability features of the kernel. 947# 948# ( If MAXSMP is enabled we just use the highest possible value and disable 949# interactive configuration. ) 950# 951 952config NR_CPUS_RANGE_BEGIN 953 int 954 default NR_CPUS_RANGE_END if MAXSMP 955 default 1 if !SMP 956 default 2 957 958config NR_CPUS_RANGE_END 959 int 960 depends on X86_32 961 default 64 if SMP && X86_BIGSMP 962 default 8 if SMP && !X86_BIGSMP 963 default 1 if !SMP 964 965config NR_CPUS_RANGE_END 966 int 967 depends on X86_64 968 default 8192 if SMP && CPUMASK_OFFSTACK 969 default 512 if SMP && !CPUMASK_OFFSTACK 970 default 1 if !SMP 971 972config NR_CPUS_DEFAULT 973 int 974 depends on X86_32 975 default 32 if X86_BIGSMP 976 default 8 if SMP 977 default 1 if !SMP 978 979config NR_CPUS_DEFAULT 980 int 981 depends on X86_64 982 default 8192 if MAXSMP 983 default 64 if SMP 984 default 1 if !SMP 985 986config NR_CPUS 987 int "Maximum number of CPUs" if SMP && !MAXSMP 988 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 989 default NR_CPUS_DEFAULT 990 help 991 This allows you to specify the maximum number of CPUs which this 992 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 993 supported value is 8192, otherwise the maximum value is 512. The 994 minimum value which makes sense is 2. 995 996 This is purely to save memory: each supported CPU adds about 8KB 997 to the kernel image. 998 999config SCHED_SMT 1000 def_bool y if SMP 1001 1002config SCHED_MC 1003 def_bool y 1004 prompt "Multi-core scheduler support" 1005 depends on SMP 1006 help 1007 Multi-core scheduler support improves the CPU scheduler's decision 1008 making when dealing with multi-core CPU chips at a cost of slightly 1009 increased overhead in some places. If unsure say N here. 1010 1011config SCHED_MC_PRIO 1012 bool "CPU core priorities scheduler support" 1013 depends on SCHED_MC && CPU_SUP_INTEL 1014 select X86_INTEL_PSTATE 1015 select CPU_FREQ 1016 default y 1017 help 1018 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1019 core ordering determined at manufacturing time, which allows 1020 certain cores to reach higher turbo frequencies (when running 1021 single threaded workloads) than others. 1022 1023 Enabling this kernel feature teaches the scheduler about 1024 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1025 scheduler's CPU selection logic accordingly, so that higher 1026 overall system performance can be achieved. 1027 1028 This feature will have no effect on CPUs without this feature. 1029 1030 If unsure say Y here. 1031 1032config UP_LATE_INIT 1033 def_bool y 1034 depends on !SMP && X86_LOCAL_APIC 1035 1036config X86_UP_APIC 1037 bool "Local APIC support on uniprocessors" if !PCI_MSI 1038 default PCI_MSI 1039 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1040 help 1041 A local APIC (Advanced Programmable Interrupt Controller) is an 1042 integrated interrupt controller in the CPU. If you have a single-CPU 1043 system which has a processor with a local APIC, you can say Y here to 1044 enable and use it. If you say Y here even though your machine doesn't 1045 have a local APIC, then the kernel will still run with no slowdown at 1046 all. The local APIC supports CPU-generated self-interrupts (timer, 1047 performance counters), and the NMI watchdog which detects hard 1048 lockups. 1049 1050config X86_UP_IOAPIC 1051 bool "IO-APIC support on uniprocessors" 1052 depends on X86_UP_APIC 1053 help 1054 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1055 SMP-capable replacement for PC-style interrupt controllers. Most 1056 SMP systems and many recent uniprocessor systems have one. 1057 1058 If you have a single-CPU system with an IO-APIC, you can say Y here 1059 to use it. If you say Y here even though your machine doesn't have 1060 an IO-APIC, then the kernel will still run with no slowdown at all. 1061 1062config X86_LOCAL_APIC 1063 def_bool y 1064 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1065 select IRQ_DOMAIN_HIERARCHY 1066 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1067 1068config X86_IO_APIC 1069 def_bool y 1070 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1071 1072config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1073 bool "Reroute for broken boot IRQs" 1074 depends on X86_IO_APIC 1075 help 1076 This option enables a workaround that fixes a source of 1077 spurious interrupts. This is recommended when threaded 1078 interrupt handling is used on systems where the generation of 1079 superfluous "boot interrupts" cannot be disabled. 1080 1081 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1082 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1083 kernel does during interrupt handling). On chipsets where this 1084 boot IRQ generation cannot be disabled, this workaround keeps 1085 the original IRQ line masked so that only the equivalent "boot 1086 IRQ" is delivered to the CPUs. The workaround also tells the 1087 kernel to set up the IRQ handler on the boot IRQ line. In this 1088 way only one interrupt is delivered to the kernel. Otherwise 1089 the spurious second interrupt may cause the kernel to bring 1090 down (vital) interrupt lines. 1091 1092 Only affects "broken" chipsets. Interrupt sharing may be 1093 increased on these systems. 1094 1095config X86_MCE 1096 bool "Machine Check / overheating reporting" 1097 select GENERIC_ALLOCATOR 1098 default y 1099 help 1100 Machine Check support allows the processor to notify the 1101 kernel if it detects a problem (e.g. overheating, data corruption). 1102 The action the kernel takes depends on the severity of the problem, 1103 ranging from warning messages to halting the machine. 1104 1105config X86_MCELOG_LEGACY 1106 bool "Support for deprecated /dev/mcelog character device" 1107 depends on X86_MCE 1108 help 1109 Enable support for /dev/mcelog which is needed by the old mcelog 1110 userspace logging daemon. Consider switching to the new generation 1111 rasdaemon solution. 1112 1113config X86_MCE_INTEL 1114 def_bool y 1115 prompt "Intel MCE features" 1116 depends on X86_MCE && X86_LOCAL_APIC 1117 help 1118 Additional support for intel specific MCE features such as 1119 the thermal monitor. 1120 1121config X86_MCE_AMD 1122 def_bool y 1123 prompt "AMD MCE features" 1124 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1125 help 1126 Additional support for AMD specific MCE features such as 1127 the DRAM Error Threshold. 1128 1129config X86_ANCIENT_MCE 1130 bool "Support for old Pentium 5 / WinChip machine checks" 1131 depends on X86_32 && X86_MCE 1132 help 1133 Include support for machine check handling on old Pentium 5 or WinChip 1134 systems. These typically need to be enabled explicitly on the command 1135 line. 1136 1137config X86_MCE_THRESHOLD 1138 depends on X86_MCE_AMD || X86_MCE_INTEL 1139 def_bool y 1140 1141config X86_MCE_INJECT 1142 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1143 tristate "Machine check injector support" 1144 help 1145 Provide support for injecting machine checks for testing purposes. 1146 If you don't know what a machine check is and you don't do kernel 1147 QA it is safe to say n. 1148 1149source "arch/x86/events/Kconfig" 1150 1151config X86_LEGACY_VM86 1152 bool "Legacy VM86 support" 1153 depends on X86_32 1154 help 1155 This option allows user programs to put the CPU into V8086 1156 mode, which is an 80286-era approximation of 16-bit real mode. 1157 1158 Some very old versions of X and/or vbetool require this option 1159 for user mode setting. Similarly, DOSEMU will use it if 1160 available to accelerate real mode DOS programs. However, any 1161 recent version of DOSEMU, X, or vbetool should be fully 1162 functional even without kernel VM86 support, as they will all 1163 fall back to software emulation. Nevertheless, if you are using 1164 a 16-bit DOS program where 16-bit performance matters, vm86 1165 mode might be faster than emulation and you might want to 1166 enable this option. 1167 1168 Note that any app that works on a 64-bit kernel is unlikely to 1169 need this option, as 64-bit kernels don't, and can't, support 1170 V8086 mode. This option is also unrelated to 16-bit protected 1171 mode and is not needed to run most 16-bit programs under Wine. 1172 1173 Enabling this option increases the complexity of the kernel 1174 and slows down exception handling a tiny bit. 1175 1176 If unsure, say N here. 1177 1178config VM86 1179 bool 1180 default X86_LEGACY_VM86 1181 1182config X86_16BIT 1183 bool "Enable support for 16-bit segments" if EXPERT 1184 default y 1185 depends on MODIFY_LDT_SYSCALL 1186 help 1187 This option is required by programs like Wine to run 16-bit 1188 protected mode legacy code on x86 processors. Disabling 1189 this option saves about 300 bytes on i386, or around 6K text 1190 plus 16K runtime memory on x86-64, 1191 1192config X86_ESPFIX32 1193 def_bool y 1194 depends on X86_16BIT && X86_32 1195 1196config X86_ESPFIX64 1197 def_bool y 1198 depends on X86_16BIT && X86_64 1199 1200config X86_VSYSCALL_EMULATION 1201 bool "Enable vsyscall emulation" if EXPERT 1202 default y 1203 depends on X86_64 1204 help 1205 This enables emulation of the legacy vsyscall page. Disabling 1206 it is roughly equivalent to booting with vsyscall=none, except 1207 that it will also disable the helpful warning if a program 1208 tries to use a vsyscall. With this option set to N, offending 1209 programs will just segfault, citing addresses of the form 1210 0xffffffffff600?00. 1211 1212 This option is required by many programs built before 2013, and 1213 care should be used even with newer programs if set to N. 1214 1215 Disabling this option saves about 7K of kernel size and 1216 possibly 4K of additional runtime pagetable memory. 1217 1218config X86_IOPL_IOPERM 1219 bool "IOPERM and IOPL Emulation" 1220 default y 1221 help 1222 This enables the ioperm() and iopl() syscalls which are necessary 1223 for legacy applications. 1224 1225 Legacy IOPL support is an overbroad mechanism which allows user 1226 space aside of accessing all 65536 I/O ports also to disable 1227 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1228 capabilities and permission from potentially active security 1229 modules. 1230 1231 The emulation restricts the functionality of the syscall to 1232 only allowing the full range I/O port access, but prevents the 1233 ability to disable interrupts from user space which would be 1234 granted if the hardware IOPL mechanism would be used. 1235 1236config TOSHIBA 1237 tristate "Toshiba Laptop support" 1238 depends on X86_32 1239 help 1240 This adds a driver to safely access the System Management Mode of 1241 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1242 not work on models with a Phoenix BIOS. The System Management Mode 1243 is used to set the BIOS and power saving options on Toshiba portables. 1244 1245 For information on utilities to make use of this driver see the 1246 Toshiba Linux utilities web site at: 1247 <http://www.buzzard.org.uk/toshiba/>. 1248 1249 Say Y if you intend to run this kernel on a Toshiba portable. 1250 Say N otherwise. 1251 1252config I8K 1253 tristate "Dell i8k legacy laptop support" 1254 select HWMON 1255 select SENSORS_DELL_SMM 1256 help 1257 This option enables legacy /proc/i8k userspace interface in hwmon 1258 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1259 temperature and allows controlling fan speeds of Dell laptops via 1260 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1261 it reports also power and hotkey status. For fan speed control is 1262 needed userspace package i8kutils. 1263 1264 Say Y if you intend to run this kernel on old Dell laptops or want to 1265 use userspace package i8kutils. 1266 Say N otherwise. 1267 1268config X86_REBOOTFIXUPS 1269 bool "Enable X86 board specific fixups for reboot" 1270 depends on X86_32 1271 help 1272 This enables chipset and/or board specific fixups to be done 1273 in order to get reboot to work correctly. This is only needed on 1274 some combinations of hardware and BIOS. The symptom, for which 1275 this config is intended, is when reboot ends with a stalled/hung 1276 system. 1277 1278 Currently, the only fixup is for the Geode machines using 1279 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1280 1281 Say Y if you want to enable the fixup. Currently, it's safe to 1282 enable this option even if you don't need it. 1283 Say N otherwise. 1284 1285config MICROCODE 1286 bool "CPU microcode loading support" 1287 default y 1288 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1289 help 1290 If you say Y here, you will be able to update the microcode on 1291 Intel and AMD processors. The Intel support is for the IA32 family, 1292 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1293 AMD support is for families 0x10 and later. You will obviously need 1294 the actual microcode binary data itself which is not shipped with 1295 the Linux kernel. 1296 1297 The preferred method to load microcode from a detached initrd is described 1298 in Documentation/x86/microcode.rst. For that you need to enable 1299 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1300 initrd for microcode blobs. 1301 1302 In addition, you can build the microcode into the kernel. For that you 1303 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1304 config option. 1305 1306config MICROCODE_INTEL 1307 bool "Intel microcode loading support" 1308 depends on MICROCODE 1309 default MICROCODE 1310 help 1311 This options enables microcode patch loading support for Intel 1312 processors. 1313 1314 For the current Intel microcode data package go to 1315 <https://downloadcenter.intel.com> and search for 1316 'Linux Processor Microcode Data File'. 1317 1318config MICROCODE_AMD 1319 bool "AMD microcode loading support" 1320 depends on MICROCODE 1321 help 1322 If you select this option, microcode patch loading support for AMD 1323 processors will be enabled. 1324 1325config MICROCODE_OLD_INTERFACE 1326 bool "Ancient loading interface (DEPRECATED)" 1327 default n 1328 depends on MICROCODE 1329 help 1330 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1331 which was used by userspace tools like iucode_tool and microcode.ctl. 1332 It is inadequate because it runs too late to be able to properly 1333 load microcode on a machine and it needs special tools. Instead, you 1334 should've switched to the early loading method with the initrd or 1335 builtin microcode by now: Documentation/x86/microcode.rst 1336 1337config X86_MSR 1338 tristate "/dev/cpu/*/msr - Model-specific register support" 1339 help 1340 This device gives privileged processes access to the x86 1341 Model-Specific Registers (MSRs). It is a character device with 1342 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1343 MSR accesses are directed to a specific CPU on multi-processor 1344 systems. 1345 1346config X86_CPUID 1347 tristate "/dev/cpu/*/cpuid - CPU information support" 1348 help 1349 This device gives processes access to the x86 CPUID instruction to 1350 be executed on a specific processor. It is a character device 1351 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1352 /dev/cpu/31/cpuid. 1353 1354choice 1355 prompt "High Memory Support" 1356 default HIGHMEM4G 1357 depends on X86_32 1358 1359config NOHIGHMEM 1360 bool "off" 1361 help 1362 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1363 However, the address space of 32-bit x86 processors is only 4 1364 Gigabytes large. That means that, if you have a large amount of 1365 physical memory, not all of it can be "permanently mapped" by the 1366 kernel. The physical memory that's not permanently mapped is called 1367 "high memory". 1368 1369 If you are compiling a kernel which will never run on a machine with 1370 more than 1 Gigabyte total physical RAM, answer "off" here (default 1371 choice and suitable for most users). This will result in a "3GB/1GB" 1372 split: 3GB are mapped so that each process sees a 3GB virtual memory 1373 space and the remaining part of the 4GB virtual memory space is used 1374 by the kernel to permanently map as much physical memory as 1375 possible. 1376 1377 If the machine has between 1 and 4 Gigabytes physical RAM, then 1378 answer "4GB" here. 1379 1380 If more than 4 Gigabytes is used then answer "64GB" here. This 1381 selection turns Intel PAE (Physical Address Extension) mode on. 1382 PAE implements 3-level paging on IA32 processors. PAE is fully 1383 supported by Linux, PAE mode is implemented on all recent Intel 1384 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1385 then the kernel will not boot on CPUs that don't support PAE! 1386 1387 The actual amount of total physical memory will either be 1388 auto detected or can be forced by using a kernel command line option 1389 such as "mem=256M". (Try "man bootparam" or see the documentation of 1390 your boot loader (lilo or loadlin) about how to pass options to the 1391 kernel at boot time.) 1392 1393 If unsure, say "off". 1394 1395config HIGHMEM4G 1396 bool "4GB" 1397 help 1398 Select this if you have a 32-bit processor and between 1 and 4 1399 gigabytes of physical RAM. 1400 1401config HIGHMEM64G 1402 bool "64GB" 1403 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1404 select X86_PAE 1405 help 1406 Select this if you have a 32-bit processor and more than 4 1407 gigabytes of physical RAM. 1408 1409endchoice 1410 1411choice 1412 prompt "Memory split" if EXPERT 1413 default VMSPLIT_3G 1414 depends on X86_32 1415 help 1416 Select the desired split between kernel and user memory. 1417 1418 If the address range available to the kernel is less than the 1419 physical memory installed, the remaining memory will be available 1420 as "high memory". Accessing high memory is a little more costly 1421 than low memory, as it needs to be mapped into the kernel first. 1422 Note that increasing the kernel address space limits the range 1423 available to user programs, making the address space there 1424 tighter. Selecting anything other than the default 3G/1G split 1425 will also likely make your kernel incompatible with binary-only 1426 kernel modules. 1427 1428 If you are not absolutely sure what you are doing, leave this 1429 option alone! 1430 1431 config VMSPLIT_3G 1432 bool "3G/1G user/kernel split" 1433 config VMSPLIT_3G_OPT 1434 depends on !X86_PAE 1435 bool "3G/1G user/kernel split (for full 1G low memory)" 1436 config VMSPLIT_2G 1437 bool "2G/2G user/kernel split" 1438 config VMSPLIT_2G_OPT 1439 depends on !X86_PAE 1440 bool "2G/2G user/kernel split (for full 2G low memory)" 1441 config VMSPLIT_1G 1442 bool "1G/3G user/kernel split" 1443endchoice 1444 1445config PAGE_OFFSET 1446 hex 1447 default 0xB0000000 if VMSPLIT_3G_OPT 1448 default 0x80000000 if VMSPLIT_2G 1449 default 0x78000000 if VMSPLIT_2G_OPT 1450 default 0x40000000 if VMSPLIT_1G 1451 default 0xC0000000 1452 depends on X86_32 1453 1454config HIGHMEM 1455 def_bool y 1456 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1457 1458config X86_PAE 1459 bool "PAE (Physical Address Extension) Support" 1460 depends on X86_32 && !HIGHMEM4G 1461 select PHYS_ADDR_T_64BIT 1462 select SWIOTLB 1463 help 1464 PAE is required for NX support, and furthermore enables 1465 larger swapspace support for non-overcommit purposes. It 1466 has the cost of more pagetable lookup overhead, and also 1467 consumes more pagetable space per process. 1468 1469config X86_5LEVEL 1470 bool "Enable 5-level page tables support" 1471 default y 1472 select DYNAMIC_MEMORY_LAYOUT 1473 select SPARSEMEM_VMEMMAP 1474 depends on X86_64 1475 help 1476 5-level paging enables access to larger address space: 1477 upto 128 PiB of virtual address space and 4 PiB of 1478 physical address space. 1479 1480 It will be supported by future Intel CPUs. 1481 1482 A kernel with the option enabled can be booted on machines that 1483 support 4- or 5-level paging. 1484 1485 See Documentation/x86/x86_64/5level-paging.rst for more 1486 information. 1487 1488 Say N if unsure. 1489 1490config X86_DIRECT_GBPAGES 1491 def_bool y 1492 depends on X86_64 1493 help 1494 Certain kernel features effectively disable kernel 1495 linear 1 GB mappings (even if the CPU otherwise 1496 supports them), so don't confuse the user by printing 1497 that we have them enabled. 1498 1499config X86_CPA_STATISTICS 1500 bool "Enable statistic for Change Page Attribute" 1501 depends on DEBUG_FS 1502 help 1503 Expose statistics about the Change Page Attribute mechanism, which 1504 helps to determine the effectiveness of preserving large and huge 1505 page mappings when mapping protections are changed. 1506 1507config AMD_MEM_ENCRYPT 1508 bool "AMD Secure Memory Encryption (SME) support" 1509 depends on X86_64 && CPU_SUP_AMD 1510 select DMA_COHERENT_POOL 1511 select DYNAMIC_PHYSICAL_MASK 1512 select ARCH_USE_MEMREMAP_PROT 1513 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1514 select INSTRUCTION_DECODER 1515 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 1516 help 1517 Say yes to enable support for the encryption of system memory. 1518 This requires an AMD processor that supports Secure Memory 1519 Encryption (SME). 1520 1521config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1522 bool "Activate AMD Secure Memory Encryption (SME) by default" 1523 default y 1524 depends on AMD_MEM_ENCRYPT 1525 help 1526 Say yes to have system memory encrypted by default if running on 1527 an AMD processor that supports Secure Memory Encryption (SME). 1528 1529 If set to Y, then the encryption of system memory can be 1530 deactivated with the mem_encrypt=off command line option. 1531 1532 If set to N, then the encryption of system memory can be 1533 activated with the mem_encrypt=on command line option. 1534 1535# Common NUMA Features 1536config NUMA 1537 bool "NUMA Memory Allocation and Scheduler Support" 1538 depends on SMP 1539 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1540 default y if X86_BIGSMP 1541 help 1542 Enable NUMA (Non-Uniform Memory Access) support. 1543 1544 The kernel will try to allocate memory used by a CPU on the 1545 local memory controller of the CPU and add some more 1546 NUMA awareness to the kernel. 1547 1548 For 64-bit this is recommended if the system is Intel Core i7 1549 (or later), AMD Opteron, or EM64T NUMA. 1550 1551 For 32-bit this is only needed if you boot a 32-bit 1552 kernel on a 64-bit NUMA platform. 1553 1554 Otherwise, you should say N. 1555 1556config AMD_NUMA 1557 def_bool y 1558 prompt "Old style AMD Opteron NUMA detection" 1559 depends on X86_64 && NUMA && PCI 1560 help 1561 Enable AMD NUMA node topology detection. You should say Y here if 1562 you have a multi processor AMD system. This uses an old method to 1563 read the NUMA configuration directly from the builtin Northbridge 1564 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1565 which also takes priority if both are compiled in. 1566 1567config X86_64_ACPI_NUMA 1568 def_bool y 1569 prompt "ACPI NUMA detection" 1570 depends on X86_64 && NUMA && ACPI && PCI 1571 select ACPI_NUMA 1572 help 1573 Enable ACPI SRAT based node topology detection. 1574 1575config NUMA_EMU 1576 bool "NUMA emulation" 1577 depends on NUMA 1578 help 1579 Enable NUMA emulation. A flat machine will be split 1580 into virtual nodes when booted with "numa=fake=N", where N is the 1581 number of nodes. This is only useful for debugging. 1582 1583config NODES_SHIFT 1584 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1585 range 1 10 1586 default "10" if MAXSMP 1587 default "6" if X86_64 1588 default "3" 1589 depends on NUMA 1590 help 1591 Specify the maximum number of NUMA Nodes available on the target 1592 system. Increases memory reserved to accommodate various tables. 1593 1594config ARCH_FLATMEM_ENABLE 1595 def_bool y 1596 depends on X86_32 && !NUMA 1597 1598config ARCH_SPARSEMEM_ENABLE 1599 def_bool y 1600 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1601 select SPARSEMEM_STATIC if X86_32 1602 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1603 1604config ARCH_SPARSEMEM_DEFAULT 1605 def_bool X86_64 || (NUMA && X86_32) 1606 1607config ARCH_SELECT_MEMORY_MODEL 1608 def_bool y 1609 depends on ARCH_SPARSEMEM_ENABLE 1610 1611config ARCH_MEMORY_PROBE 1612 bool "Enable sysfs memory/probe interface" 1613 depends on X86_64 && MEMORY_HOTPLUG 1614 help 1615 This option enables a sysfs memory/probe interface for testing. 1616 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1617 If you are unsure how to answer this question, answer N. 1618 1619config ARCH_PROC_KCORE_TEXT 1620 def_bool y 1621 depends on X86_64 && PROC_KCORE 1622 1623config ILLEGAL_POINTER_VALUE 1624 hex 1625 default 0 if X86_32 1626 default 0xdead000000000000 if X86_64 1627 1628config X86_PMEM_LEGACY_DEVICE 1629 bool 1630 1631config X86_PMEM_LEGACY 1632 tristate "Support non-standard NVDIMMs and ADR protected memory" 1633 depends on PHYS_ADDR_T_64BIT 1634 depends on BLK_DEV 1635 select X86_PMEM_LEGACY_DEVICE 1636 select NUMA_KEEP_MEMINFO if NUMA 1637 select LIBNVDIMM 1638 help 1639 Treat memory marked using the non-standard e820 type of 12 as used 1640 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1641 The kernel will offer these regions to the 'pmem' driver so 1642 they can be used for persistent storage. 1643 1644 Say Y if unsure. 1645 1646config HIGHPTE 1647 bool "Allocate 3rd-level pagetables from highmem" 1648 depends on HIGHMEM 1649 help 1650 The VM uses one page table entry for each page of physical memory. 1651 For systems with a lot of RAM, this can be wasteful of precious 1652 low memory. Setting this option will put user-space page table 1653 entries in high memory. 1654 1655config X86_CHECK_BIOS_CORRUPTION 1656 bool "Check for low memory corruption" 1657 help 1658 Periodically check for memory corruption in low memory, which 1659 is suspected to be caused by BIOS. Even when enabled in the 1660 configuration, it is disabled at runtime. Enable it by 1661 setting "memory_corruption_check=1" on the kernel command 1662 line. By default it scans the low 64k of memory every 60 1663 seconds; see the memory_corruption_check_size and 1664 memory_corruption_check_period parameters in 1665 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1666 1667 When enabled with the default parameters, this option has 1668 almost no overhead, as it reserves a relatively small amount 1669 of memory and scans it infrequently. It both detects corruption 1670 and prevents it from affecting the running system. 1671 1672 It is, however, intended as a diagnostic tool; if repeatable 1673 BIOS-originated corruption always affects the same memory, 1674 you can use memmap= to prevent the kernel from using that 1675 memory. 1676 1677config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1678 bool "Set the default setting of memory_corruption_check" 1679 depends on X86_CHECK_BIOS_CORRUPTION 1680 default y 1681 help 1682 Set whether the default state of memory_corruption_check is 1683 on or off. 1684 1685config X86_RESERVE_LOW 1686 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1687 default 64 1688 range 4 640 1689 help 1690 Specify the amount of low memory to reserve for the BIOS. 1691 1692 The first page contains BIOS data structures that the kernel 1693 must not use, so that page must always be reserved. 1694 1695 By default we reserve the first 64K of physical RAM, as a 1696 number of BIOSes are known to corrupt that memory range 1697 during events such as suspend/resume or monitor cable 1698 insertion, so it must not be used by the kernel. 1699 1700 You can set this to 4 if you are absolutely sure that you 1701 trust the BIOS to get all its memory reservations and usages 1702 right. If you know your BIOS have problems beyond the 1703 default 64K area, you can set this to 640 to avoid using the 1704 entire low memory range. 1705 1706 If you have doubts about the BIOS (e.g. suspend/resume does 1707 not work or there's kernel crashes after certain hardware 1708 hotplug events) then you might want to enable 1709 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1710 typical corruption patterns. 1711 1712 Leave this to the default value of 64 if you are unsure. 1713 1714config MATH_EMULATION 1715 bool 1716 depends on MODIFY_LDT_SYSCALL 1717 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1718 help 1719 Linux can emulate a math coprocessor (used for floating point 1720 operations) if you don't have one. 486DX and Pentium processors have 1721 a math coprocessor built in, 486SX and 386 do not, unless you added 1722 a 487DX or 387, respectively. (The messages during boot time can 1723 give you some hints here ["man dmesg"].) Everyone needs either a 1724 coprocessor or this emulation. 1725 1726 If you don't have a math coprocessor, you need to say Y here; if you 1727 say Y here even though you have a coprocessor, the coprocessor will 1728 be used nevertheless. (This behavior can be changed with the kernel 1729 command line option "no387", which comes handy if your coprocessor 1730 is broken. Try "man bootparam" or see the documentation of your boot 1731 loader (lilo or loadlin) about how to pass options to the kernel at 1732 boot time.) This means that it is a good idea to say Y here if you 1733 intend to use this kernel on different machines. 1734 1735 More information about the internals of the Linux math coprocessor 1736 emulation can be found in <file:arch/x86/math-emu/README>. 1737 1738 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1739 kernel, it won't hurt. 1740 1741config MTRR 1742 def_bool y 1743 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1744 help 1745 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1746 the Memory Type Range Registers (MTRRs) may be used to control 1747 processor access to memory ranges. This is most useful if you have 1748 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1749 allows bus write transfers to be combined into a larger transfer 1750 before bursting over the PCI/AGP bus. This can increase performance 1751 of image write operations 2.5 times or more. Saying Y here creates a 1752 /proc/mtrr file which may be used to manipulate your processor's 1753 MTRRs. Typically the X server should use this. 1754 1755 This code has a reasonably generic interface so that similar 1756 control registers on other processors can be easily supported 1757 as well: 1758 1759 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1760 Registers (ARRs) which provide a similar functionality to MTRRs. For 1761 these, the ARRs are used to emulate the MTRRs. 1762 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1763 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1764 write-combining. All of these processors are supported by this code 1765 and it makes sense to say Y here if you have one of them. 1766 1767 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1768 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1769 can lead to all sorts of problems, so it's good to say Y here. 1770 1771 You can safely say Y even if your machine doesn't have MTRRs, you'll 1772 just add about 9 KB to your kernel. 1773 1774 See <file:Documentation/x86/mtrr.rst> for more information. 1775 1776config MTRR_SANITIZER 1777 def_bool y 1778 prompt "MTRR cleanup support" 1779 depends on MTRR 1780 help 1781 Convert MTRR layout from continuous to discrete, so X drivers can 1782 add writeback entries. 1783 1784 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1785 The largest mtrr entry size for a continuous block can be set with 1786 mtrr_chunk_size. 1787 1788 If unsure, say Y. 1789 1790config MTRR_SANITIZER_ENABLE_DEFAULT 1791 int "MTRR cleanup enable value (0-1)" 1792 range 0 1 1793 default "0" 1794 depends on MTRR_SANITIZER 1795 help 1796 Enable mtrr cleanup default value 1797 1798config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1799 int "MTRR cleanup spare reg num (0-7)" 1800 range 0 7 1801 default "1" 1802 depends on MTRR_SANITIZER 1803 help 1804 mtrr cleanup spare entries default, it can be changed via 1805 mtrr_spare_reg_nr=N on the kernel command line. 1806 1807config X86_PAT 1808 def_bool y 1809 prompt "x86 PAT support" if EXPERT 1810 depends on MTRR 1811 help 1812 Use PAT attributes to setup page level cache control. 1813 1814 PATs are the modern equivalents of MTRRs and are much more 1815 flexible than MTRRs. 1816 1817 Say N here if you see bootup problems (boot crash, boot hang, 1818 spontaneous reboots) or a non-working video driver. 1819 1820 If unsure, say Y. 1821 1822config ARCH_USES_PG_UNCACHED 1823 def_bool y 1824 depends on X86_PAT 1825 1826config ARCH_RANDOM 1827 def_bool y 1828 prompt "x86 architectural random number generator" if EXPERT 1829 help 1830 Enable the x86 architectural RDRAND instruction 1831 (Intel Bull Mountain technology) to generate random numbers. 1832 If supported, this is a high bandwidth, cryptographically 1833 secure hardware random number generator. 1834 1835config X86_SMAP 1836 def_bool y 1837 prompt "Supervisor Mode Access Prevention" if EXPERT 1838 help 1839 Supervisor Mode Access Prevention (SMAP) is a security 1840 feature in newer Intel processors. There is a small 1841 performance cost if this enabled and turned on; there is 1842 also a small increase in the kernel size if this is enabled. 1843 1844 If unsure, say Y. 1845 1846config X86_UMIP 1847 def_bool y 1848 prompt "User Mode Instruction Prevention" if EXPERT 1849 help 1850 User Mode Instruction Prevention (UMIP) is a security feature in 1851 some x86 processors. If enabled, a general protection fault is 1852 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1853 executed in user mode. These instructions unnecessarily expose 1854 information about the hardware state. 1855 1856 The vast majority of applications do not use these instructions. 1857 For the very few that do, software emulation is provided in 1858 specific cases in protected and virtual-8086 modes. Emulated 1859 results are dummy. 1860 1861config X86_INTEL_MEMORY_PROTECTION_KEYS 1862 prompt "Memory Protection Keys" 1863 def_bool y 1864 # Note: only available in 64-bit mode 1865 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1866 select ARCH_USES_HIGH_VMA_FLAGS 1867 select ARCH_HAS_PKEYS 1868 help 1869 Memory Protection Keys provides a mechanism for enforcing 1870 page-based protections, but without requiring modification of the 1871 page tables when an application changes protection domains. 1872 1873 For details, see Documentation/core-api/protection-keys.rst 1874 1875 If unsure, say y. 1876 1877choice 1878 prompt "TSX enable mode" 1879 depends on CPU_SUP_INTEL 1880 default X86_INTEL_TSX_MODE_OFF 1881 help 1882 Intel's TSX (Transactional Synchronization Extensions) feature 1883 allows to optimize locking protocols through lock elision which 1884 can lead to a noticeable performance boost. 1885 1886 On the other hand it has been shown that TSX can be exploited 1887 to form side channel attacks (e.g. TAA) and chances are there 1888 will be more of those attacks discovered in the future. 1889 1890 Therefore TSX is not enabled by default (aka tsx=off). An admin 1891 might override this decision by tsx=on the command line parameter. 1892 Even with TSX enabled, the kernel will attempt to enable the best 1893 possible TAA mitigation setting depending on the microcode available 1894 for the particular machine. 1895 1896 This option allows to set the default tsx mode between tsx=on, =off 1897 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1898 details. 1899 1900 Say off if not sure, auto if TSX is in use but it should be used on safe 1901 platforms or on if TSX is in use and the security aspect of tsx is not 1902 relevant. 1903 1904config X86_INTEL_TSX_MODE_OFF 1905 bool "off" 1906 help 1907 TSX is disabled if possible - equals to tsx=off command line parameter. 1908 1909config X86_INTEL_TSX_MODE_ON 1910 bool "on" 1911 help 1912 TSX is always enabled on TSX capable HW - equals the tsx=on command 1913 line parameter. 1914 1915config X86_INTEL_TSX_MODE_AUTO 1916 bool "auto" 1917 help 1918 TSX is enabled on TSX capable HW that is believed to be safe against 1919 side channel attacks- equals the tsx=auto command line parameter. 1920endchoice 1921 1922config X86_SGX 1923 bool "Software Guard eXtensions (SGX)" 1924 depends on X86_64 && CPU_SUP_INTEL 1925 depends on CRYPTO=y 1926 depends on CRYPTO_SHA256=y 1927 select SRCU 1928 select MMU_NOTIFIER 1929 select NUMA_KEEP_MEMINFO if NUMA 1930 help 1931 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1932 that can be used by applications to set aside private regions of code 1933 and data, referred to as enclaves. An enclave's private memory can 1934 only be accessed by code running within the enclave. Accesses from 1935 outside the enclave, including other enclaves, are disallowed by 1936 hardware. 1937 1938 If unsure, say N. 1939 1940config EFI 1941 bool "EFI runtime service support" 1942 depends on ACPI 1943 select UCS2_STRING 1944 select EFI_RUNTIME_WRAPPERS 1945 help 1946 This enables the kernel to use EFI runtime services that are 1947 available (such as the EFI variable services). 1948 1949 This option is only useful on systems that have EFI firmware. 1950 In addition, you should use the latest ELILO loader available 1951 at <http://elilo.sourceforge.net> in order to take advantage 1952 of EFI runtime services. However, even with this option, the 1953 resultant kernel should continue to boot on existing non-EFI 1954 platforms. 1955 1956config EFI_STUB 1957 bool "EFI stub support" 1958 depends on EFI && !X86_USE_3DNOW 1959 depends on $(cc-option,-mabi=ms) || X86_32 1960 select RELOCATABLE 1961 help 1962 This kernel feature allows a bzImage to be loaded directly 1963 by EFI firmware without the use of a bootloader. 1964 1965 See Documentation/admin-guide/efi-stub.rst for more information. 1966 1967config EFI_MIXED 1968 bool "EFI mixed-mode support" 1969 depends on EFI_STUB && X86_64 1970 help 1971 Enabling this feature allows a 64-bit kernel to be booted 1972 on a 32-bit firmware, provided that your CPU supports 64-bit 1973 mode. 1974 1975 Note that it is not possible to boot a mixed-mode enabled 1976 kernel via the EFI boot stub - a bootloader that supports 1977 the EFI handover protocol must be used. 1978 1979 If unsure, say N. 1980 1981source "kernel/Kconfig.hz" 1982 1983config KEXEC 1984 bool "kexec system call" 1985 select KEXEC_CORE 1986 help 1987 kexec is a system call that implements the ability to shutdown your 1988 current kernel, and to start another kernel. It is like a reboot 1989 but it is independent of the system firmware. And like a reboot 1990 you can start any kernel with it, not just Linux. 1991 1992 The name comes from the similarity to the exec system call. 1993 1994 It is an ongoing process to be certain the hardware in a machine 1995 is properly shutdown, so do not be surprised if this code does not 1996 initially work for you. As of this writing the exact hardware 1997 interface is strongly in flux, so no good recommendation can be 1998 made. 1999 2000config KEXEC_FILE 2001 bool "kexec file based system call" 2002 select KEXEC_CORE 2003 select BUILD_BIN2C 2004 depends on X86_64 2005 depends on CRYPTO=y 2006 depends on CRYPTO_SHA256=y 2007 help 2008 This is new version of kexec system call. This system call is 2009 file based and takes file descriptors as system call argument 2010 for kernel and initramfs as opposed to list of segments as 2011 accepted by previous system call. 2012 2013config ARCH_HAS_KEXEC_PURGATORY 2014 def_bool KEXEC_FILE 2015 2016config KEXEC_SIG 2017 bool "Verify kernel signature during kexec_file_load() syscall" 2018 depends on KEXEC_FILE 2019 help 2020 2021 This option makes the kexec_file_load() syscall check for a valid 2022 signature of the kernel image. The image can still be loaded without 2023 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2024 there's a signature that we can check, then it must be valid. 2025 2026 In addition to this option, you need to enable signature 2027 verification for the corresponding kernel image type being 2028 loaded in order for this to work. 2029 2030config KEXEC_SIG_FORCE 2031 bool "Require a valid signature in kexec_file_load() syscall" 2032 depends on KEXEC_SIG 2033 help 2034 This option makes kernel signature verification mandatory for 2035 the kexec_file_load() syscall. 2036 2037config KEXEC_BZIMAGE_VERIFY_SIG 2038 bool "Enable bzImage signature verification support" 2039 depends on KEXEC_SIG 2040 depends on SIGNED_PE_FILE_VERIFICATION 2041 select SYSTEM_TRUSTED_KEYRING 2042 help 2043 Enable bzImage signature verification support. 2044 2045config CRASH_DUMP 2046 bool "kernel crash dumps" 2047 depends on X86_64 || (X86_32 && HIGHMEM) 2048 help 2049 Generate crash dump after being started by kexec. 2050 This should be normally only set in special crash dump kernels 2051 which are loaded in the main kernel with kexec-tools into 2052 a specially reserved region and then later executed after 2053 a crash by kdump/kexec. The crash dump kernel must be compiled 2054 to a memory address not used by the main kernel or BIOS using 2055 PHYSICAL_START, or it must be built as a relocatable image 2056 (CONFIG_RELOCATABLE=y). 2057 For more details see Documentation/admin-guide/kdump/kdump.rst 2058 2059config KEXEC_JUMP 2060 bool "kexec jump" 2061 depends on KEXEC && HIBERNATION 2062 help 2063 Jump between original kernel and kexeced kernel and invoke 2064 code in physical address mode via KEXEC 2065 2066config PHYSICAL_START 2067 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2068 default "0x1000000" 2069 help 2070 This gives the physical address where the kernel is loaded. 2071 2072 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2073 bzImage will decompress itself to above physical address and 2074 run from there. Otherwise, bzImage will run from the address where 2075 it has been loaded by the boot loader and will ignore above physical 2076 address. 2077 2078 In normal kdump cases one does not have to set/change this option 2079 as now bzImage can be compiled as a completely relocatable image 2080 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2081 address. This option is mainly useful for the folks who don't want 2082 to use a bzImage for capturing the crash dump and want to use a 2083 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2084 to be specifically compiled to run from a specific memory area 2085 (normally a reserved region) and this option comes handy. 2086 2087 So if you are using bzImage for capturing the crash dump, 2088 leave the value here unchanged to 0x1000000 and set 2089 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2090 for capturing the crash dump change this value to start of 2091 the reserved region. In other words, it can be set based on 2092 the "X" value as specified in the "crashkernel=YM@XM" 2093 command line boot parameter passed to the panic-ed 2094 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2095 for more details about crash dumps. 2096 2097 Usage of bzImage for capturing the crash dump is recommended as 2098 one does not have to build two kernels. Same kernel can be used 2099 as production kernel and capture kernel. Above option should have 2100 gone away after relocatable bzImage support is introduced. But it 2101 is present because there are users out there who continue to use 2102 vmlinux for dump capture. This option should go away down the 2103 line. 2104 2105 Don't change this unless you know what you are doing. 2106 2107config RELOCATABLE 2108 bool "Build a relocatable kernel" 2109 default y 2110 help 2111 This builds a kernel image that retains relocation information 2112 so it can be loaded someplace besides the default 1MB. 2113 The relocations tend to make the kernel binary about 10% larger, 2114 but are discarded at runtime. 2115 2116 One use is for the kexec on panic case where the recovery kernel 2117 must live at a different physical address than the primary 2118 kernel. 2119 2120 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2121 it has been loaded at and the compile time physical address 2122 (CONFIG_PHYSICAL_START) is used as the minimum location. 2123 2124config RANDOMIZE_BASE 2125 bool "Randomize the address of the kernel image (KASLR)" 2126 depends on RELOCATABLE 2127 default y 2128 help 2129 In support of Kernel Address Space Layout Randomization (KASLR), 2130 this randomizes the physical address at which the kernel image 2131 is decompressed and the virtual address where the kernel 2132 image is mapped, as a security feature that deters exploit 2133 attempts relying on knowledge of the location of kernel 2134 code internals. 2135 2136 On 64-bit, the kernel physical and virtual addresses are 2137 randomized separately. The physical address will be anywhere 2138 between 16MB and the top of physical memory (up to 64TB). The 2139 virtual address will be randomized from 16MB up to 1GB (9 bits 2140 of entropy). Note that this also reduces the memory space 2141 available to kernel modules from 1.5GB to 1GB. 2142 2143 On 32-bit, the kernel physical and virtual addresses are 2144 randomized together. They will be randomized from 16MB up to 2145 512MB (8 bits of entropy). 2146 2147 Entropy is generated using the RDRAND instruction if it is 2148 supported. If RDTSC is supported, its value is mixed into 2149 the entropy pool as well. If neither RDRAND nor RDTSC are 2150 supported, then entropy is read from the i8254 timer. The 2151 usable entropy is limited by the kernel being built using 2152 2GB addressing, and that PHYSICAL_ALIGN must be at a 2153 minimum of 2MB. As a result, only 10 bits of entropy are 2154 theoretically possible, but the implementations are further 2155 limited due to memory layouts. 2156 2157 If unsure, say Y. 2158 2159# Relocation on x86 needs some additional build support 2160config X86_NEED_RELOCS 2161 def_bool y 2162 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2163 2164config PHYSICAL_ALIGN 2165 hex "Alignment value to which kernel should be aligned" 2166 default "0x200000" 2167 range 0x2000 0x1000000 if X86_32 2168 range 0x200000 0x1000000 if X86_64 2169 help 2170 This value puts the alignment restrictions on physical address 2171 where kernel is loaded and run from. Kernel is compiled for an 2172 address which meets above alignment restriction. 2173 2174 If bootloader loads the kernel at a non-aligned address and 2175 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2176 address aligned to above value and run from there. 2177 2178 If bootloader loads the kernel at a non-aligned address and 2179 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2180 load address and decompress itself to the address it has been 2181 compiled for and run from there. The address for which kernel is 2182 compiled already meets above alignment restrictions. Hence the 2183 end result is that kernel runs from a physical address meeting 2184 above alignment restrictions. 2185 2186 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2187 this value must be a multiple of 0x200000. 2188 2189 Don't change this unless you know what you are doing. 2190 2191config DYNAMIC_MEMORY_LAYOUT 2192 bool 2193 help 2194 This option makes base addresses of vmalloc and vmemmap as well as 2195 __PAGE_OFFSET movable during boot. 2196 2197config RANDOMIZE_MEMORY 2198 bool "Randomize the kernel memory sections" 2199 depends on X86_64 2200 depends on RANDOMIZE_BASE 2201 select DYNAMIC_MEMORY_LAYOUT 2202 default RANDOMIZE_BASE 2203 help 2204 Randomizes the base virtual address of kernel memory sections 2205 (physical memory mapping, vmalloc & vmemmap). This security feature 2206 makes exploits relying on predictable memory locations less reliable. 2207 2208 The order of allocations remains unchanged. Entropy is generated in 2209 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2210 configuration have in average 30,000 different possible virtual 2211 addresses for each memory section. 2212 2213 If unsure, say Y. 2214 2215config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2216 hex "Physical memory mapping padding" if EXPERT 2217 depends on RANDOMIZE_MEMORY 2218 default "0xa" if MEMORY_HOTPLUG 2219 default "0x0" 2220 range 0x1 0x40 if MEMORY_HOTPLUG 2221 range 0x0 0x40 2222 help 2223 Define the padding in terabytes added to the existing physical 2224 memory size during kernel memory randomization. It is useful 2225 for memory hotplug support but reduces the entropy available for 2226 address randomization. 2227 2228 If unsure, leave at the default value. 2229 2230config HOTPLUG_CPU 2231 def_bool y 2232 depends on SMP 2233 2234config BOOTPARAM_HOTPLUG_CPU0 2235 bool "Set default setting of cpu0_hotpluggable" 2236 depends on HOTPLUG_CPU 2237 help 2238 Set whether default state of cpu0_hotpluggable is on or off. 2239 2240 Say Y here to enable CPU0 hotplug by default. If this switch 2241 is turned on, there is no need to give cpu0_hotplug kernel 2242 parameter and the CPU0 hotplug feature is enabled by default. 2243 2244 Please note: there are two known CPU0 dependencies if you want 2245 to enable the CPU0 hotplug feature either by this switch or by 2246 cpu0_hotplug kernel parameter. 2247 2248 First, resume from hibernate or suspend always starts from CPU0. 2249 So hibernate and suspend are prevented if CPU0 is offline. 2250 2251 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2252 offline if any interrupt can not migrate out of CPU0. There may 2253 be other CPU0 dependencies. 2254 2255 Please make sure the dependencies are under your control before 2256 you enable this feature. 2257 2258 Say N if you don't want to enable CPU0 hotplug feature by default. 2259 You still can enable the CPU0 hotplug feature at boot by kernel 2260 parameter cpu0_hotplug. 2261 2262config DEBUG_HOTPLUG_CPU0 2263 def_bool n 2264 prompt "Debug CPU0 hotplug" 2265 depends on HOTPLUG_CPU 2266 help 2267 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2268 soon as possible and boots up userspace with CPU0 offlined. User 2269 can online CPU0 back after boot time. 2270 2271 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2272 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2273 compilation or giving cpu0_hotplug kernel parameter at boot. 2274 2275 If unsure, say N. 2276 2277config COMPAT_VDSO 2278 def_bool n 2279 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2280 depends on COMPAT_32 2281 help 2282 Certain buggy versions of glibc will crash if they are 2283 presented with a 32-bit vDSO that is not mapped at the address 2284 indicated in its segment table. 2285 2286 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2287 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2288 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2289 the only released version with the bug, but OpenSUSE 9 2290 contains a buggy "glibc 2.3.2". 2291 2292 The symptom of the bug is that everything crashes on startup, saying: 2293 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2294 2295 Saying Y here changes the default value of the vdso32 boot 2296 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2297 This works around the glibc bug but hurts performance. 2298 2299 If unsure, say N: if you are compiling your own kernel, you 2300 are unlikely to be using a buggy version of glibc. 2301 2302choice 2303 prompt "vsyscall table for legacy applications" 2304 depends on X86_64 2305 default LEGACY_VSYSCALL_XONLY 2306 help 2307 Legacy user code that does not know how to find the vDSO expects 2308 to be able to issue three syscalls by calling fixed addresses in 2309 kernel space. Since this location is not randomized with ASLR, 2310 it can be used to assist security vulnerability exploitation. 2311 2312 This setting can be changed at boot time via the kernel command 2313 line parameter vsyscall=[emulate|xonly|none]. 2314 2315 On a system with recent enough glibc (2.14 or newer) and no 2316 static binaries, you can say None without a performance penalty 2317 to improve security. 2318 2319 If unsure, select "Emulate execution only". 2320 2321 config LEGACY_VSYSCALL_EMULATE 2322 bool "Full emulation" 2323 help 2324 The kernel traps and emulates calls into the fixed vsyscall 2325 address mapping. This makes the mapping non-executable, but 2326 it still contains readable known contents, which could be 2327 used in certain rare security vulnerability exploits. This 2328 configuration is recommended when using legacy userspace 2329 that still uses vsyscalls along with legacy binary 2330 instrumentation tools that require code to be readable. 2331 2332 An example of this type of legacy userspace is running 2333 Pin on an old binary that still uses vsyscalls. 2334 2335 config LEGACY_VSYSCALL_XONLY 2336 bool "Emulate execution only" 2337 help 2338 The kernel traps and emulates calls into the fixed vsyscall 2339 address mapping and does not allow reads. This 2340 configuration is recommended when userspace might use the 2341 legacy vsyscall area but support for legacy binary 2342 instrumentation of legacy code is not needed. It mitigates 2343 certain uses of the vsyscall area as an ASLR-bypassing 2344 buffer. 2345 2346 config LEGACY_VSYSCALL_NONE 2347 bool "None" 2348 help 2349 There will be no vsyscall mapping at all. This will 2350 eliminate any risk of ASLR bypass due to the vsyscall 2351 fixed address mapping. Attempts to use the vsyscalls 2352 will be reported to dmesg, so that either old or 2353 malicious userspace programs can be identified. 2354 2355endchoice 2356 2357config CMDLINE_BOOL 2358 bool "Built-in kernel command line" 2359 help 2360 Allow for specifying boot arguments to the kernel at 2361 build time. On some systems (e.g. embedded ones), it is 2362 necessary or convenient to provide some or all of the 2363 kernel boot arguments with the kernel itself (that is, 2364 to not rely on the boot loader to provide them.) 2365 2366 To compile command line arguments into the kernel, 2367 set this option to 'Y', then fill in the 2368 boot arguments in CONFIG_CMDLINE. 2369 2370 Systems with fully functional boot loaders (i.e. non-embedded) 2371 should leave this option set to 'N'. 2372 2373config CMDLINE 2374 string "Built-in kernel command string" 2375 depends on CMDLINE_BOOL 2376 default "" 2377 help 2378 Enter arguments here that should be compiled into the kernel 2379 image and used at boot time. If the boot loader provides a 2380 command line at boot time, it is appended to this string to 2381 form the full kernel command line, when the system boots. 2382 2383 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2384 change this behavior. 2385 2386 In most cases, the command line (whether built-in or provided 2387 by the boot loader) should specify the device for the root 2388 file system. 2389 2390config CMDLINE_OVERRIDE 2391 bool "Built-in command line overrides boot loader arguments" 2392 depends on CMDLINE_BOOL && CMDLINE != "" 2393 help 2394 Set this option to 'Y' to have the kernel ignore the boot loader 2395 command line, and use ONLY the built-in command line. 2396 2397 This is used to work around broken boot loaders. This should 2398 be set to 'N' under normal conditions. 2399 2400config MODIFY_LDT_SYSCALL 2401 bool "Enable the LDT (local descriptor table)" if EXPERT 2402 default y 2403 help 2404 Linux can allow user programs to install a per-process x86 2405 Local Descriptor Table (LDT) using the modify_ldt(2) system 2406 call. This is required to run 16-bit or segmented code such as 2407 DOSEMU or some Wine programs. It is also used by some very old 2408 threading libraries. 2409 2410 Enabling this feature adds a small amount of overhead to 2411 context switches and increases the low-level kernel attack 2412 surface. Disabling it removes the modify_ldt(2) system call. 2413 2414 Saying 'N' here may make sense for embedded or server kernels. 2415 2416source "kernel/livepatch/Kconfig" 2417 2418endmenu 2419 2420config ARCH_HAS_ADD_PAGES 2421 def_bool y 2422 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2423 2424config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2425 def_bool y 2426 2427config USE_PERCPU_NUMA_NODE_ID 2428 def_bool y 2429 depends on NUMA 2430 2431menu "Power management and ACPI options" 2432 2433config ARCH_HIBERNATION_HEADER 2434 def_bool y 2435 depends on HIBERNATION 2436 2437source "kernel/power/Kconfig" 2438 2439source "drivers/acpi/Kconfig" 2440 2441config X86_APM_BOOT 2442 def_bool y 2443 depends on APM 2444 2445menuconfig APM 2446 tristate "APM (Advanced Power Management) BIOS support" 2447 depends on X86_32 && PM_SLEEP 2448 help 2449 APM is a BIOS specification for saving power using several different 2450 techniques. This is mostly useful for battery powered laptops with 2451 APM compliant BIOSes. If you say Y here, the system time will be 2452 reset after a RESUME operation, the /proc/apm device will provide 2453 battery status information, and user-space programs will receive 2454 notification of APM "events" (e.g. battery status change). 2455 2456 If you select "Y" here, you can disable actual use of the APM 2457 BIOS by passing the "apm=off" option to the kernel at boot time. 2458 2459 Note that the APM support is almost completely disabled for 2460 machines with more than one CPU. 2461 2462 In order to use APM, you will need supporting software. For location 2463 and more information, read <file:Documentation/power/apm-acpi.rst> 2464 and the Battery Powered Linux mini-HOWTO, available from 2465 <http://www.tldp.org/docs.html#howto>. 2466 2467 This driver does not spin down disk drives (see the hdparm(8) 2468 manpage ("man 8 hdparm") for that), and it doesn't turn off 2469 VESA-compliant "green" monitors. 2470 2471 This driver does not support the TI 4000M TravelMate and the ACER 2472 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2473 desktop machines also don't have compliant BIOSes, and this driver 2474 may cause those machines to panic during the boot phase. 2475 2476 Generally, if you don't have a battery in your machine, there isn't 2477 much point in using this driver and you should say N. If you get 2478 random kernel OOPSes or reboots that don't seem to be related to 2479 anything, try disabling/enabling this option (or disabling/enabling 2480 APM in your BIOS). 2481 2482 Some other things you should try when experiencing seemingly random, 2483 "weird" problems: 2484 2485 1) make sure that you have enough swap space and that it is 2486 enabled. 2487 2) pass the "no-hlt" option to the kernel 2488 3) switch on floating point emulation in the kernel and pass 2489 the "no387" option to the kernel 2490 4) pass the "floppy=nodma" option to the kernel 2491 5) pass the "mem=4M" option to the kernel (thereby disabling 2492 all but the first 4 MB of RAM) 2493 6) make sure that the CPU is not over clocked. 2494 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2495 8) disable the cache from your BIOS settings 2496 9) install a fan for the video card or exchange video RAM 2497 10) install a better fan for the CPU 2498 11) exchange RAM chips 2499 12) exchange the motherboard. 2500 2501 To compile this driver as a module, choose M here: the 2502 module will be called apm. 2503 2504if APM 2505 2506config APM_IGNORE_USER_SUSPEND 2507 bool "Ignore USER SUSPEND" 2508 help 2509 This option will ignore USER SUSPEND requests. On machines with a 2510 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2511 series notebooks, it is necessary to say Y because of a BIOS bug. 2512 2513config APM_DO_ENABLE 2514 bool "Enable PM at boot time" 2515 help 2516 Enable APM features at boot time. From page 36 of the APM BIOS 2517 specification: "When disabled, the APM BIOS does not automatically 2518 power manage devices, enter the Standby State, enter the Suspend 2519 State, or take power saving steps in response to CPU Idle calls." 2520 This driver will make CPU Idle calls when Linux is idle (unless this 2521 feature is turned off -- see "Do CPU IDLE calls", below). This 2522 should always save battery power, but more complicated APM features 2523 will be dependent on your BIOS implementation. You may need to turn 2524 this option off if your computer hangs at boot time when using APM 2525 support, or if it beeps continuously instead of suspending. Turn 2526 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2527 T400CDT. This is off by default since most machines do fine without 2528 this feature. 2529 2530config APM_CPU_IDLE 2531 depends on CPU_IDLE 2532 bool "Make CPU Idle calls when idle" 2533 help 2534 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2535 On some machines, this can activate improved power savings, such as 2536 a slowed CPU clock rate, when the machine is idle. These idle calls 2537 are made after the idle loop has run for some length of time (e.g., 2538 333 mS). On some machines, this will cause a hang at boot time or 2539 whenever the CPU becomes idle. (On machines with more than one CPU, 2540 this option does nothing.) 2541 2542config APM_DISPLAY_BLANK 2543 bool "Enable console blanking using APM" 2544 help 2545 Enable console blanking using the APM. Some laptops can use this to 2546 turn off the LCD backlight when the screen blanker of the Linux 2547 virtual console blanks the screen. Note that this is only used by 2548 the virtual console screen blanker, and won't turn off the backlight 2549 when using the X Window system. This also doesn't have anything to 2550 do with your VESA-compliant power-saving monitor. Further, this 2551 option doesn't work for all laptops -- it might not turn off your 2552 backlight at all, or it might print a lot of errors to the console, 2553 especially if you are using gpm. 2554 2555config APM_ALLOW_INTS 2556 bool "Allow interrupts during APM BIOS calls" 2557 help 2558 Normally we disable external interrupts while we are making calls to 2559 the APM BIOS as a measure to lessen the effects of a badly behaving 2560 BIOS implementation. The BIOS should reenable interrupts if it 2561 needs to. Unfortunately, some BIOSes do not -- especially those in 2562 many of the newer IBM Thinkpads. If you experience hangs when you 2563 suspend, try setting this to Y. Otherwise, say N. 2564 2565endif # APM 2566 2567source "drivers/cpufreq/Kconfig" 2568 2569source "drivers/cpuidle/Kconfig" 2570 2571source "drivers/idle/Kconfig" 2572 2573endmenu 2574 2575 2576menu "Bus options (PCI etc.)" 2577 2578choice 2579 prompt "PCI access mode" 2580 depends on X86_32 && PCI 2581 default PCI_GOANY 2582 help 2583 On PCI systems, the BIOS can be used to detect the PCI devices and 2584 determine their configuration. However, some old PCI motherboards 2585 have BIOS bugs and may crash if this is done. Also, some embedded 2586 PCI-based systems don't have any BIOS at all. Linux can also try to 2587 detect the PCI hardware directly without using the BIOS. 2588 2589 With this option, you can specify how Linux should detect the 2590 PCI devices. If you choose "BIOS", the BIOS will be used, 2591 if you choose "Direct", the BIOS won't be used, and if you 2592 choose "MMConfig", then PCI Express MMCONFIG will be used. 2593 If you choose "Any", the kernel will try MMCONFIG, then the 2594 direct access method and falls back to the BIOS if that doesn't 2595 work. If unsure, go with the default, which is "Any". 2596 2597config PCI_GOBIOS 2598 bool "BIOS" 2599 2600config PCI_GOMMCONFIG 2601 bool "MMConfig" 2602 2603config PCI_GODIRECT 2604 bool "Direct" 2605 2606config PCI_GOOLPC 2607 bool "OLPC XO-1" 2608 depends on OLPC 2609 2610config PCI_GOANY 2611 bool "Any" 2612 2613endchoice 2614 2615config PCI_BIOS 2616 def_bool y 2617 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2618 2619# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2620config PCI_DIRECT 2621 def_bool y 2622 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2623 2624config PCI_MMCONFIG 2625 bool "Support mmconfig PCI config space access" if X86_64 2626 default y 2627 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2628 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2629 2630config PCI_OLPC 2631 def_bool y 2632 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2633 2634config PCI_XEN 2635 def_bool y 2636 depends on PCI && XEN 2637 select SWIOTLB_XEN 2638 2639config MMCONF_FAM10H 2640 def_bool y 2641 depends on X86_64 && PCI_MMCONFIG && ACPI 2642 2643config PCI_CNB20LE_QUIRK 2644 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2645 depends on PCI 2646 help 2647 Read the PCI windows out of the CNB20LE host bridge. This allows 2648 PCI hotplug to work on systems with the CNB20LE chipset which do 2649 not have ACPI. 2650 2651 There's no public spec for this chipset, and this functionality 2652 is known to be incomplete. 2653 2654 You should say N unless you know you need this. 2655 2656config ISA_BUS 2657 bool "ISA bus support on modern systems" if EXPERT 2658 help 2659 Expose ISA bus device drivers and options available for selection and 2660 configuration. Enable this option if your target machine has an ISA 2661 bus. ISA is an older system, displaced by PCI and newer bus 2662 architectures -- if your target machine is modern, it probably does 2663 not have an ISA bus. 2664 2665 If unsure, say N. 2666 2667# x86_64 have no ISA slots, but can have ISA-style DMA. 2668config ISA_DMA_API 2669 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2670 default y 2671 help 2672 Enables ISA-style DMA support for devices requiring such controllers. 2673 If unsure, say Y. 2674 2675if X86_32 2676 2677config ISA 2678 bool "ISA support" 2679 help 2680 Find out whether you have ISA slots on your motherboard. ISA is the 2681 name of a bus system, i.e. the way the CPU talks to the other stuff 2682 inside your box. Other bus systems are PCI, EISA, MicroChannel 2683 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2684 newer boards don't support it. If you have ISA, say Y, otherwise N. 2685 2686config SCx200 2687 tristate "NatSemi SCx200 support" 2688 help 2689 This provides basic support for National Semiconductor's 2690 (now AMD's) Geode processors. The driver probes for the 2691 PCI-IDs of several on-chip devices, so its a good dependency 2692 for other scx200_* drivers. 2693 2694 If compiled as a module, the driver is named scx200. 2695 2696config SCx200HR_TIMER 2697 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2698 depends on SCx200 2699 default y 2700 help 2701 This driver provides a clocksource built upon the on-chip 2702 27MHz high-resolution timer. Its also a workaround for 2703 NSC Geode SC-1100's buggy TSC, which loses time when the 2704 processor goes idle (as is done by the scheduler). The 2705 other workaround is idle=poll boot option. 2706 2707config OLPC 2708 bool "One Laptop Per Child support" 2709 depends on !X86_PAE 2710 select GPIOLIB 2711 select OF 2712 select OF_PROMTREE 2713 select IRQ_DOMAIN 2714 select OLPC_EC 2715 help 2716 Add support for detecting the unique features of the OLPC 2717 XO hardware. 2718 2719config OLPC_XO1_PM 2720 bool "OLPC XO-1 Power Management" 2721 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2722 help 2723 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2724 2725config OLPC_XO1_RTC 2726 bool "OLPC XO-1 Real Time Clock" 2727 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2728 help 2729 Add support for the XO-1 real time clock, which can be used as a 2730 programmable wakeup source. 2731 2732config OLPC_XO1_SCI 2733 bool "OLPC XO-1 SCI extras" 2734 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2735 depends on INPUT=y 2736 select POWER_SUPPLY 2737 help 2738 Add support for SCI-based features of the OLPC XO-1 laptop: 2739 - EC-driven system wakeups 2740 - Power button 2741 - Ebook switch 2742 - Lid switch 2743 - AC adapter status updates 2744 - Battery status updates 2745 2746config OLPC_XO15_SCI 2747 bool "OLPC XO-1.5 SCI extras" 2748 depends on OLPC && ACPI 2749 select POWER_SUPPLY 2750 help 2751 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2752 - EC-driven system wakeups 2753 - AC adapter status updates 2754 - Battery status updates 2755 2756config ALIX 2757 bool "PCEngines ALIX System Support (LED setup)" 2758 select GPIOLIB 2759 help 2760 This option enables system support for the PCEngines ALIX. 2761 At present this just sets up LEDs for GPIO control on 2762 ALIX2/3/6 boards. However, other system specific setup should 2763 get added here. 2764 2765 Note: You must still enable the drivers for GPIO and LED support 2766 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2767 2768 Note: You have to set alix.force=1 for boards with Award BIOS. 2769 2770config NET5501 2771 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2772 select GPIOLIB 2773 help 2774 This option enables system support for the Soekris Engineering net5501. 2775 2776config GEOS 2777 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2778 select GPIOLIB 2779 depends on DMI 2780 help 2781 This option enables system support for the Traverse Technologies GEOS. 2782 2783config TS5500 2784 bool "Technologic Systems TS-5500 platform support" 2785 depends on MELAN 2786 select CHECK_SIGNATURE 2787 select NEW_LEDS 2788 select LEDS_CLASS 2789 help 2790 This option enables system support for the Technologic Systems TS-5500. 2791 2792endif # X86_32 2793 2794config AMD_NB 2795 def_bool y 2796 depends on CPU_SUP_AMD && PCI 2797 2798config X86_SYSFB 2799 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2800 help 2801 Firmwares often provide initial graphics framebuffers so the BIOS, 2802 bootloader or kernel can show basic video-output during boot for 2803 user-guidance and debugging. Historically, x86 used the VESA BIOS 2804 Extensions and EFI-framebuffers for this, which are mostly limited 2805 to x86. 2806 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2807 framebuffers so the new generic system-framebuffer drivers can be 2808 used on x86. If the framebuffer is not compatible with the generic 2809 modes, it is advertised as fallback platform framebuffer so legacy 2810 drivers like efifb, vesafb and uvesafb can pick it up. 2811 If this option is not selected, all system framebuffers are always 2812 marked as fallback platform framebuffers as usual. 2813 2814 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2815 not be able to pick up generic system framebuffers if this option 2816 is selected. You are highly encouraged to enable simplefb as 2817 replacement if you select this option. simplefb can correctly deal 2818 with generic system framebuffers. But you should still keep vesafb 2819 and others enabled as fallback if a system framebuffer is 2820 incompatible with simplefb. 2821 2822 If unsure, say Y. 2823 2824endmenu 2825 2826 2827menu "Binary Emulations" 2828 2829config IA32_EMULATION 2830 bool "IA32 Emulation" 2831 depends on X86_64 2832 select ARCH_WANT_OLD_COMPAT_IPC 2833 select BINFMT_ELF 2834 select COMPAT_OLD_SIGACTION 2835 help 2836 Include code to run legacy 32-bit programs under a 2837 64-bit kernel. You should likely turn this on, unless you're 2838 100% sure that you don't have any 32-bit programs left. 2839 2840config IA32_AOUT 2841 tristate "IA32 a.out support" 2842 depends on IA32_EMULATION 2843 depends on BROKEN 2844 help 2845 Support old a.out binaries in the 32bit emulation. 2846 2847config X86_X32 2848 bool "x32 ABI for 64-bit mode" 2849 depends on X86_64 2850 help 2851 Include code to run binaries for the x32 native 32-bit ABI 2852 for 64-bit processors. An x32 process gets access to the 2853 full 64-bit register file and wide data path while leaving 2854 pointers at 32 bits for smaller memory footprint. 2855 2856 You will need a recent binutils (2.22 or later) with 2857 elf32_x86_64 support enabled to compile a kernel with this 2858 option set. 2859 2860config COMPAT_32 2861 def_bool y 2862 depends on IA32_EMULATION || X86_32 2863 select HAVE_UID16 2864 select OLD_SIGSUSPEND3 2865 2866config COMPAT 2867 def_bool y 2868 depends on IA32_EMULATION || X86_X32 2869 2870if COMPAT 2871config COMPAT_FOR_U64_ALIGNMENT 2872 def_bool y 2873 2874config SYSVIPC_COMPAT 2875 def_bool y 2876 depends on SYSVIPC 2877endif 2878 2879endmenu 2880 2881 2882config HAVE_ATOMIC_IOMAP 2883 def_bool y 2884 depends on X86_32 2885 2886source "drivers/firmware/Kconfig" 2887 2888source "arch/x86/kvm/Kconfig" 2889 2890source "arch/x86/Kconfig.assembler" 2891