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 37config FORCE_DYNAMIC_FTRACE 38 def_bool y 39 depends on X86_32 40 depends on FUNCTION_TRACER 41 select DYNAMIC_FTRACE 42 help 43 We keep the static function tracing (!DYNAMIC_FTRACE) around 44 in order to test the non static function tracing in the 45 generic code, as other architectures still use it. But we 46 only need to keep it around for x86_64. No need to keep it 47 for x86_32. For x86_32, force DYNAMIC_FTRACE. 48# 49# Arch settings 50# 51# ( Note that options that are marked 'if X86_64' could in principle be 52# ported to 32-bit as well. ) 53# 54config X86 55 def_bool y 56 # 57 # Note: keep this list sorted alphabetically 58 # 59 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 60 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 61 select ARCH_32BIT_OFF_T if X86_32 62 select ARCH_CLOCKSOURCE_INIT 63 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 64 select ARCH_HAS_DEBUG_VIRTUAL 65 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 66 select ARCH_HAS_DEVMEM_IS_ALLOWED 67 select ARCH_HAS_EARLY_DEBUG if KGDB 68 select ARCH_HAS_ELF_RANDOMIZE 69 select ARCH_HAS_FAST_MULTIPLIER 70 select ARCH_HAS_FILTER_PGPROT 71 select ARCH_HAS_FORTIFY_SOURCE 72 select ARCH_HAS_GCOV_PROFILE_ALL 73 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 74 select ARCH_HAS_MEM_ENCRYPT 75 select ARCH_HAS_MEMBARRIER_SYNC_CORE 76 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 77 select ARCH_HAS_PMEM_API if X86_64 78 select ARCH_HAS_PTE_DEVMAP if X86_64 79 select ARCH_HAS_PTE_SPECIAL 80 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 81 select ARCH_HAS_COPY_MC if X86_64 82 select ARCH_HAS_SET_MEMORY 83 select ARCH_HAS_SET_DIRECT_MAP 84 select ARCH_HAS_STRICT_KERNEL_RWX 85 select ARCH_HAS_STRICT_MODULE_RWX 86 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 87 select ARCH_HAS_SYSCALL_WRAPPER 88 select ARCH_HAS_UBSAN_SANITIZE_ALL 89 select ARCH_HAS_DEBUG_WX 90 select ARCH_HAVE_NMI_SAFE_CMPXCHG 91 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 92 select ARCH_MIGHT_HAVE_PC_PARPORT 93 select ARCH_MIGHT_HAVE_PC_SERIO 94 select ARCH_STACKWALK 95 select ARCH_SUPPORTS_ACPI 96 select ARCH_SUPPORTS_ATOMIC_RMW 97 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 98 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 99 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 100 select ARCH_SUPPORTS_LTO_CLANG if X86_64 101 select ARCH_SUPPORTS_LTO_CLANG_THIN if X86_64 102 select ARCH_USE_BUILTIN_BSWAP 103 select ARCH_USE_QUEUED_RWLOCKS 104 select ARCH_USE_QUEUED_SPINLOCKS 105 select ARCH_USE_SYM_ANNOTATIONS 106 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 107 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 108 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 109 select ARCH_WANT_HUGE_PMD_SHARE 110 select ARCH_WANT_LD_ORPHAN_WARN 111 select ARCH_WANTS_THP_SWAP if X86_64 112 select BUILDTIME_TABLE_SORT 113 select CLKEVT_I8253 114 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 115 select CLOCKSOURCE_WATCHDOG 116 select DCACHE_WORD_ACCESS 117 select EDAC_ATOMIC_SCRUB 118 select EDAC_SUPPORT 119 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 120 select GENERIC_CLOCKEVENTS_MIN_ADJUST 121 select GENERIC_CMOS_UPDATE 122 select GENERIC_CPU_AUTOPROBE 123 select GENERIC_CPU_VULNERABILITIES 124 select GENERIC_EARLY_IOREMAP 125 select GENERIC_ENTRY 126 select GENERIC_FIND_FIRST_BIT 127 select GENERIC_IOMAP 128 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 129 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 130 select GENERIC_IRQ_MIGRATION if SMP 131 select GENERIC_IRQ_PROBE 132 select GENERIC_IRQ_RESERVATION_MODE 133 select GENERIC_IRQ_SHOW 134 select GENERIC_PENDING_IRQ if SMP 135 select GENERIC_PTDUMP 136 select GENERIC_SMP_IDLE_THREAD 137 select GENERIC_STRNCPY_FROM_USER 138 select GENERIC_STRNLEN_USER 139 select GENERIC_TIME_VSYSCALL 140 select GENERIC_GETTIMEOFDAY 141 select GENERIC_VDSO_TIME_NS 142 select GUP_GET_PTE_LOW_HIGH if X86_PAE 143 select HARDIRQS_SW_RESEND 144 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 145 select HAVE_ACPI_APEI if ACPI 146 select HAVE_ACPI_APEI_NMI if ACPI 147 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 148 select HAVE_ARCH_AUDITSYSCALL 149 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 150 select HAVE_ARCH_JUMP_LABEL 151 select HAVE_ARCH_JUMP_LABEL_RELATIVE 152 select HAVE_ARCH_KASAN if X86_64 153 select HAVE_ARCH_KASAN_VMALLOC if X86_64 154 select HAVE_ARCH_KFENCE 155 select HAVE_ARCH_KGDB 156 select HAVE_ARCH_MMAP_RND_BITS if MMU 157 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 158 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 159 select HAVE_ARCH_PREL32_RELOCATIONS 160 select HAVE_ARCH_SECCOMP_FILTER 161 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 162 select HAVE_ARCH_STACKLEAK 163 select HAVE_ARCH_TRACEHOOK 164 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 165 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 166 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 167 select HAVE_ARCH_VMAP_STACK if X86_64 168 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 169 select HAVE_ARCH_WITHIN_STACK_FRAMES 170 select HAVE_ASM_MODVERSIONS 171 select HAVE_CMPXCHG_DOUBLE 172 select HAVE_CMPXCHG_LOCAL 173 select HAVE_CONTEXT_TRACKING if X86_64 174 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING 175 select HAVE_C_RECORDMCOUNT 176 select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION 177 select HAVE_DEBUG_KMEMLEAK 178 select HAVE_DMA_CONTIGUOUS 179 select HAVE_DYNAMIC_FTRACE 180 select HAVE_DYNAMIC_FTRACE_WITH_REGS 181 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 182 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 183 select HAVE_EBPF_JIT 184 select HAVE_EFFICIENT_UNALIGNED_ACCESS 185 select HAVE_EISA 186 select HAVE_EXIT_THREAD 187 select HAVE_FAST_GUP 188 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 189 select HAVE_FTRACE_MCOUNT_RECORD 190 select HAVE_FUNCTION_GRAPH_TRACER 191 select HAVE_FUNCTION_TRACER 192 select HAVE_GCC_PLUGINS 193 select HAVE_HW_BREAKPOINT 194 select HAVE_IDE 195 select HAVE_IOREMAP_PROT 196 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 197 select HAVE_IRQ_TIME_ACCOUNTING 198 select HAVE_KERNEL_BZIP2 199 select HAVE_KERNEL_GZIP 200 select HAVE_KERNEL_LZ4 201 select HAVE_KERNEL_LZMA 202 select HAVE_KERNEL_LZO 203 select HAVE_KERNEL_XZ 204 select HAVE_KERNEL_ZSTD 205 select HAVE_KPROBES 206 select HAVE_KPROBES_ON_FTRACE 207 select HAVE_FUNCTION_ERROR_INJECTION 208 select HAVE_KRETPROBES 209 select HAVE_KVM 210 select HAVE_LIVEPATCH if X86_64 211 select HAVE_MIXED_BREAKPOINTS_REGS 212 select HAVE_MOD_ARCH_SPECIFIC 213 select HAVE_MOVE_PMD 214 select HAVE_MOVE_PUD 215 select HAVE_NMI 216 select HAVE_OPTPROBES 217 select HAVE_PCSPKR_PLATFORM 218 select HAVE_PERF_EVENTS 219 select HAVE_PERF_EVENTS_NMI 220 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 221 select HAVE_PCI 222 select HAVE_PERF_REGS 223 select HAVE_PERF_USER_STACK_DUMP 224 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 225 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 226 select HAVE_REGS_AND_STACK_ACCESS_API 227 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 228 select HAVE_FUNCTION_ARG_ACCESS_API 229 select HAVE_SOFTIRQ_ON_OWN_STACK 230 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 231 select HAVE_STACK_VALIDATION if X86_64 232 select HAVE_STATIC_CALL 233 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 234 select HAVE_PREEMPT_DYNAMIC 235 select HAVE_RSEQ 236 select HAVE_SYSCALL_TRACEPOINTS 237 select HAVE_UNSTABLE_SCHED_CLOCK 238 select HAVE_USER_RETURN_NOTIFIER 239 select HAVE_GENERIC_VDSO 240 select HOTPLUG_SMT if SMP 241 select IRQ_FORCED_THREADING 242 select NEED_SG_DMA_LENGTH 243 select PCI_DOMAINS if PCI 244 select PCI_LOCKLESS_CONFIG if PCI 245 select PERF_EVENTS 246 select RTC_LIB 247 select RTC_MC146818_LIB 248 select SPARSE_IRQ 249 select SRCU 250 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 251 select SYSCTL_EXCEPTION_TRACE 252 select THREAD_INFO_IN_TASK 253 select USER_STACKTRACE_SUPPORT 254 select VIRT_TO_BUS 255 select HAVE_ARCH_KCSAN if X86_64 256 select X86_FEATURE_NAMES if PROC_FS 257 select PROC_PID_ARCH_STATUS if PROC_FS 258 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 259 260config INSTRUCTION_DECODER 261 def_bool y 262 depends on KPROBES || PERF_EVENTS || UPROBES 263 264config OUTPUT_FORMAT 265 string 266 default "elf32-i386" if X86_32 267 default "elf64-x86-64" if X86_64 268 269config LOCKDEP_SUPPORT 270 def_bool y 271 272config STACKTRACE_SUPPORT 273 def_bool y 274 275config MMU 276 def_bool y 277 278config ARCH_MMAP_RND_BITS_MIN 279 default 28 if 64BIT 280 default 8 281 282config ARCH_MMAP_RND_BITS_MAX 283 default 32 if 64BIT 284 default 16 285 286config ARCH_MMAP_RND_COMPAT_BITS_MIN 287 default 8 288 289config ARCH_MMAP_RND_COMPAT_BITS_MAX 290 default 16 291 292config SBUS 293 bool 294 295config GENERIC_ISA_DMA 296 def_bool y 297 depends on ISA_DMA_API 298 299config GENERIC_BUG 300 def_bool y 301 depends on BUG 302 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 303 304config GENERIC_BUG_RELATIVE_POINTERS 305 bool 306 307config ARCH_MAY_HAVE_PC_FDC 308 def_bool y 309 depends on ISA_DMA_API 310 311config GENERIC_CALIBRATE_DELAY 312 def_bool y 313 314config ARCH_HAS_CPU_RELAX 315 def_bool y 316 317config ARCH_HAS_CACHE_LINE_SIZE 318 def_bool y 319 320config ARCH_HAS_FILTER_PGPROT 321 def_bool y 322 323config HAVE_SETUP_PER_CPU_AREA 324 def_bool y 325 326config NEED_PER_CPU_EMBED_FIRST_CHUNK 327 def_bool y 328 329config NEED_PER_CPU_PAGE_FIRST_CHUNK 330 def_bool y 331 332config ARCH_HIBERNATION_POSSIBLE 333 def_bool y 334 335config ARCH_SUSPEND_POSSIBLE 336 def_bool y 337 338config ARCH_WANT_GENERAL_HUGETLB 339 def_bool y 340 341config ZONE_DMA32 342 def_bool y if X86_64 343 344config AUDIT_ARCH 345 def_bool y if X86_64 346 347config KASAN_SHADOW_OFFSET 348 hex 349 depends on KASAN 350 default 0xdffffc0000000000 351 352config HAVE_INTEL_TXT 353 def_bool y 354 depends on INTEL_IOMMU && ACPI 355 356config X86_32_SMP 357 def_bool y 358 depends on X86_32 && SMP 359 360config X86_64_SMP 361 def_bool y 362 depends on X86_64 && SMP 363 364config ARCH_SUPPORTS_UPROBES 365 def_bool y 366 367config FIX_EARLYCON_MEM 368 def_bool y 369 370config DYNAMIC_PHYSICAL_MASK 371 bool 372 373config PGTABLE_LEVELS 374 int 375 default 5 if X86_5LEVEL 376 default 4 if X86_64 377 default 3 if X86_PAE 378 default 2 379 380config CC_HAS_SANE_STACKPROTECTOR 381 bool 382 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 383 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 384 help 385 We have to make sure stack protector is unconditionally disabled if 386 the compiler produces broken code or if it does not let us control 387 the segment on 32-bit kernels. 388 389menu "Processor type and features" 390 391config ZONE_DMA 392 bool "DMA memory allocation support" if EXPERT 393 default y 394 help 395 DMA memory allocation support allows devices with less than 32-bit 396 addressing to allocate within the first 16MB of address space. 397 Disable if no such devices will be used. 398 399 If unsure, say Y. 400 401config SMP 402 bool "Symmetric multi-processing support" 403 help 404 This enables support for systems with more than one CPU. If you have 405 a system with only one CPU, say N. If you have a system with more 406 than one CPU, say Y. 407 408 If you say N here, the kernel will run on uni- and multiprocessor 409 machines, but will use only one CPU of a multiprocessor machine. If 410 you say Y here, the kernel will run on many, but not all, 411 uniprocessor machines. On a uniprocessor machine, the kernel 412 will run faster if you say N here. 413 414 Note that if you say Y here and choose architecture "586" or 415 "Pentium" under "Processor family", the kernel will not work on 486 416 architectures. Similarly, multiprocessor kernels for the "PPro" 417 architecture may not work on all Pentium based boards. 418 419 People using multiprocessor machines who say Y here should also say 420 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 421 Management" code will be disabled if you say Y here. 422 423 See also <file:Documentation/x86/i386/IO-APIC.rst>, 424 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 425 <http://www.tldp.org/docs.html#howto>. 426 427 If you don't know what to do here, say N. 428 429config X86_FEATURE_NAMES 430 bool "Processor feature human-readable names" if EMBEDDED 431 default y 432 help 433 This option compiles in a table of x86 feature bits and corresponding 434 names. This is required to support /proc/cpuinfo and a few kernel 435 messages. You can disable this to save space, at the expense of 436 making those few kernel messages show numeric feature bits instead. 437 438 If in doubt, say Y. 439 440config X86_X2APIC 441 bool "Support x2apic" 442 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 443 help 444 This enables x2apic support on CPUs that have this feature. 445 446 This allows 32-bit apic IDs (so it can support very large systems), 447 and accesses the local apic via MSRs not via mmio. 448 449 If you don't know what to do here, say N. 450 451config X86_MPPARSE 452 bool "Enable MPS table" if ACPI 453 default y 454 depends on X86_LOCAL_APIC 455 help 456 For old smp systems that do not have proper acpi support. Newer systems 457 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 458 459config GOLDFISH 460 def_bool y 461 depends on X86_GOLDFISH 462 463config RETPOLINE 464 bool "Avoid speculative indirect branches in kernel" 465 default y 466 help 467 Compile kernel with the retpoline compiler options to guard against 468 kernel-to-user data leaks by avoiding speculative indirect 469 branches. Requires a compiler with -mindirect-branch=thunk-extern 470 support for full protection. The kernel may run slower. 471 472config X86_CPU_RESCTRL 473 bool "x86 CPU resource control support" 474 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 475 select KERNFS 476 select PROC_CPU_RESCTRL if PROC_FS 477 help 478 Enable x86 CPU resource control support. 479 480 Provide support for the allocation and monitoring of system resources 481 usage by the CPU. 482 483 Intel calls this Intel Resource Director Technology 484 (Intel(R) RDT). More information about RDT can be found in the 485 Intel x86 Architecture Software Developer Manual. 486 487 AMD calls this AMD Platform Quality of Service (AMD QoS). 488 More information about AMD QoS can be found in the AMD64 Technology 489 Platform Quality of Service Extensions manual. 490 491 Say N if unsure. 492 493if X86_32 494config X86_BIGSMP 495 bool "Support for big SMP systems with more than 8 CPUs" 496 depends on SMP 497 help 498 This option is needed for the systems that have more than 8 CPUs. 499 500config X86_EXTENDED_PLATFORM 501 bool "Support for extended (non-PC) x86 platforms" 502 default y 503 help 504 If you disable this option then the kernel will only support 505 standard PC platforms. (which covers the vast majority of 506 systems out there.) 507 508 If you enable this option then you'll be able to select support 509 for the following (non-PC) 32 bit x86 platforms: 510 Goldfish (Android emulator) 511 AMD Elan 512 RDC R-321x SoC 513 SGI 320/540 (Visual Workstation) 514 STA2X11-based (e.g. Northville) 515 Moorestown MID devices 516 517 If you have one of these systems, or if you want to build a 518 generic distribution kernel, say Y here - otherwise say N. 519endif 520 521if X86_64 522config X86_EXTENDED_PLATFORM 523 bool "Support for extended (non-PC) x86 platforms" 524 default y 525 help 526 If you disable this option then the kernel will only support 527 standard PC platforms. (which covers the vast majority of 528 systems out there.) 529 530 If you enable this option then you'll be able to select support 531 for the following (non-PC) 64 bit x86 platforms: 532 Numascale NumaChip 533 ScaleMP vSMP 534 SGI Ultraviolet 535 536 If you have one of these systems, or if you want to build a 537 generic distribution kernel, say Y here - otherwise say N. 538endif 539# This is an alphabetically sorted list of 64 bit extended platforms 540# Please maintain the alphabetic order if and when there are additions 541config X86_NUMACHIP 542 bool "Numascale NumaChip" 543 depends on X86_64 544 depends on X86_EXTENDED_PLATFORM 545 depends on NUMA 546 depends on SMP 547 depends on X86_X2APIC 548 depends on PCI_MMCONFIG 549 help 550 Adds support for Numascale NumaChip large-SMP systems. Needed to 551 enable more than ~168 cores. 552 If you don't have one of these, you should say N here. 553 554config X86_VSMP 555 bool "ScaleMP vSMP" 556 select HYPERVISOR_GUEST 557 select PARAVIRT 558 depends on X86_64 && PCI 559 depends on X86_EXTENDED_PLATFORM 560 depends on SMP 561 help 562 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 563 supposed to run on these EM64T-based machines. Only choose this option 564 if you have one of these machines. 565 566config X86_UV 567 bool "SGI Ultraviolet" 568 depends on X86_64 569 depends on X86_EXTENDED_PLATFORM 570 depends on NUMA 571 depends on EFI 572 depends on KEXEC_CORE 573 depends on X86_X2APIC 574 depends on PCI 575 help 576 This option is needed in order to support SGI Ultraviolet systems. 577 If you don't have one of these, you should say N here. 578 579# Following is an alphabetically sorted list of 32 bit extended platforms 580# Please maintain the alphabetic order if and when there are additions 581 582config X86_GOLDFISH 583 bool "Goldfish (Virtual Platform)" 584 depends on X86_EXTENDED_PLATFORM 585 help 586 Enable support for the Goldfish virtual platform used primarily 587 for Android development. Unless you are building for the Android 588 Goldfish emulator say N here. 589 590config X86_INTEL_CE 591 bool "CE4100 TV platform" 592 depends on PCI 593 depends on PCI_GODIRECT 594 depends on X86_IO_APIC 595 depends on X86_32 596 depends on X86_EXTENDED_PLATFORM 597 select X86_REBOOTFIXUPS 598 select OF 599 select OF_EARLY_FLATTREE 600 help 601 Select for the Intel CE media processor (CE4100) SOC. 602 This option compiles in support for the CE4100 SOC for settop 603 boxes and media devices. 604 605config X86_INTEL_MID 606 bool "Intel MID platform support" 607 depends on X86_EXTENDED_PLATFORM 608 depends on X86_PLATFORM_DEVICES 609 depends on PCI 610 depends on X86_64 || (PCI_GOANY && X86_32) 611 depends on X86_IO_APIC 612 select I2C 613 select DW_APB_TIMER 614 select APB_TIMER 615 select INTEL_SCU_PCI 616 select MFD_INTEL_MSIC 617 help 618 Select to build a kernel capable of supporting Intel MID (Mobile 619 Internet Device) platform systems which do not have the PCI legacy 620 interfaces. If you are building for a PC class system say N here. 621 622 Intel MID platforms are based on an Intel processor and chipset which 623 consume less power than most of the x86 derivatives. 624 625config X86_INTEL_QUARK 626 bool "Intel Quark platform support" 627 depends on X86_32 628 depends on X86_EXTENDED_PLATFORM 629 depends on X86_PLATFORM_DEVICES 630 depends on X86_TSC 631 depends on PCI 632 depends on PCI_GOANY 633 depends on X86_IO_APIC 634 select IOSF_MBI 635 select INTEL_IMR 636 select COMMON_CLK 637 help 638 Select to include support for Quark X1000 SoC. 639 Say Y here if you have a Quark based system such as the Arduino 640 compatible Intel Galileo. 641 642config X86_INTEL_LPSS 643 bool "Intel Low Power Subsystem Support" 644 depends on X86 && ACPI && PCI 645 select COMMON_CLK 646 select PINCTRL 647 select IOSF_MBI 648 help 649 Select to build support for Intel Low Power Subsystem such as 650 found on Intel Lynxpoint PCH. Selecting this option enables 651 things like clock tree (common clock framework) and pincontrol 652 which are needed by the LPSS peripheral drivers. 653 654config X86_AMD_PLATFORM_DEVICE 655 bool "AMD ACPI2Platform devices support" 656 depends on ACPI 657 select COMMON_CLK 658 select PINCTRL 659 help 660 Select to interpret AMD specific ACPI device to platform device 661 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 662 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 663 implemented under PINCTRL subsystem. 664 665config IOSF_MBI 666 tristate "Intel SoC IOSF Sideband support for SoC platforms" 667 depends on PCI 668 help 669 This option enables sideband register access support for Intel SoC 670 platforms. On these platforms the IOSF sideband is used in lieu of 671 MSR's for some register accesses, mostly but not limited to thermal 672 and power. Drivers may query the availability of this device to 673 determine if they need the sideband in order to work on these 674 platforms. The sideband is available on the following SoC products. 675 This list is not meant to be exclusive. 676 - BayTrail 677 - Braswell 678 - Quark 679 680 You should say Y if you are running a kernel on one of these SoC's. 681 682config IOSF_MBI_DEBUG 683 bool "Enable IOSF sideband access through debugfs" 684 depends on IOSF_MBI && DEBUG_FS 685 help 686 Select this option to expose the IOSF sideband access registers (MCR, 687 MDR, MCRX) through debugfs to write and read register information from 688 different units on the SoC. This is most useful for obtaining device 689 state information for debug and analysis. As this is a general access 690 mechanism, users of this option would have specific knowledge of the 691 device they want to access. 692 693 If you don't require the option or are in doubt, say N. 694 695config X86_RDC321X 696 bool "RDC R-321x SoC" 697 depends on X86_32 698 depends on X86_EXTENDED_PLATFORM 699 select M486 700 select X86_REBOOTFIXUPS 701 help 702 This option is needed for RDC R-321x system-on-chip, also known 703 as R-8610-(G). 704 If you don't have one of these chips, you should say N here. 705 706config X86_32_NON_STANDARD 707 bool "Support non-standard 32-bit SMP architectures" 708 depends on X86_32 && SMP 709 depends on X86_EXTENDED_PLATFORM 710 help 711 This option compiles in the bigsmp and STA2X11 default 712 subarchitectures. It is intended for a generic binary 713 kernel. If you select them all, kernel will probe it one by 714 one and will fallback to default. 715 716# Alphabetically sorted list of Non standard 32 bit platforms 717 718config X86_SUPPORTS_MEMORY_FAILURE 719 def_bool y 720 # MCE code calls memory_failure(): 721 depends on X86_MCE 722 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 723 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 724 depends on X86_64 || !SPARSEMEM 725 select ARCH_SUPPORTS_MEMORY_FAILURE 726 727config STA2X11 728 bool "STA2X11 Companion Chip Support" 729 depends on X86_32_NON_STANDARD && PCI 730 select SWIOTLB 731 select MFD_STA2X11 732 select GPIOLIB 733 help 734 This adds support for boards based on the STA2X11 IO-Hub, 735 a.k.a. "ConneXt". The chip is used in place of the standard 736 PC chipset, so all "standard" peripherals are missing. If this 737 option is selected the kernel will still be able to boot on 738 standard PC machines. 739 740config X86_32_IRIS 741 tristate "Eurobraille/Iris poweroff module" 742 depends on X86_32 743 help 744 The Iris machines from EuroBraille do not have APM or ACPI support 745 to shut themselves down properly. A special I/O sequence is 746 needed to do so, which is what this module does at 747 kernel shutdown. 748 749 This is only for Iris machines from EuroBraille. 750 751 If unused, say N. 752 753config SCHED_OMIT_FRAME_POINTER 754 def_bool y 755 prompt "Single-depth WCHAN output" 756 depends on X86 757 help 758 Calculate simpler /proc/<PID>/wchan values. If this option 759 is disabled then wchan values will recurse back to the 760 caller function. This provides more accurate wchan values, 761 at the expense of slightly more scheduling overhead. 762 763 If in doubt, say "Y". 764 765menuconfig HYPERVISOR_GUEST 766 bool "Linux guest support" 767 help 768 Say Y here to enable options for running Linux under various hyper- 769 visors. This option enables basic hypervisor detection and platform 770 setup. 771 772 If you say N, all options in this submenu will be skipped and 773 disabled, and Linux guest support won't be built in. 774 775if HYPERVISOR_GUEST 776 777config PARAVIRT 778 bool "Enable paravirtualization code" 779 depends on HAVE_STATIC_CALL 780 help 781 This changes the kernel so it can modify itself when it is run 782 under a hypervisor, potentially improving performance significantly 783 over full virtualization. However, when run without a hypervisor 784 the kernel is theoretically slower and slightly larger. 785 786config PARAVIRT_XXL 787 bool 788 789config PARAVIRT_DEBUG 790 bool "paravirt-ops debugging" 791 depends on PARAVIRT && DEBUG_KERNEL 792 help 793 Enable to debug paravirt_ops internals. Specifically, BUG if 794 a paravirt_op is missing when it is called. 795 796config PARAVIRT_SPINLOCKS 797 bool "Paravirtualization layer for spinlocks" 798 depends on PARAVIRT && SMP 799 help 800 Paravirtualized spinlocks allow a pvops backend to replace the 801 spinlock implementation with something virtualization-friendly 802 (for example, block the virtual CPU rather than spinning). 803 804 It has a minimal impact on native kernels and gives a nice performance 805 benefit on paravirtualized KVM / Xen kernels. 806 807 If you are unsure how to answer this question, answer Y. 808 809config X86_HV_CALLBACK_VECTOR 810 def_bool n 811 812source "arch/x86/xen/Kconfig" 813 814config KVM_GUEST 815 bool "KVM Guest support (including kvmclock)" 816 depends on PARAVIRT 817 select PARAVIRT_CLOCK 818 select ARCH_CPUIDLE_HALTPOLL 819 select X86_HV_CALLBACK_VECTOR 820 default y 821 help 822 This option enables various optimizations for running under the KVM 823 hypervisor. It includes a paravirtualized clock, so that instead 824 of relying on a PIT (or probably other) emulation by the 825 underlying device model, the host provides the guest with 826 timing infrastructure such as time of day, and system time 827 828config ARCH_CPUIDLE_HALTPOLL 829 def_bool n 830 prompt "Disable host haltpoll when loading haltpoll driver" 831 help 832 If virtualized under KVM, disable host haltpoll. 833 834config PVH 835 bool "Support for running PVH guests" 836 help 837 This option enables the PVH entry point for guest virtual machines 838 as specified in the x86/HVM direct boot ABI. 839 840config PARAVIRT_TIME_ACCOUNTING 841 bool "Paravirtual steal time accounting" 842 depends on PARAVIRT 843 help 844 Select this option to enable fine granularity task steal time 845 accounting. Time spent executing other tasks in parallel with 846 the current vCPU is discounted from the vCPU power. To account for 847 that, there can be a small performance impact. 848 849 If in doubt, say N here. 850 851config PARAVIRT_CLOCK 852 bool 853 854config JAILHOUSE_GUEST 855 bool "Jailhouse non-root cell support" 856 depends on X86_64 && PCI 857 select X86_PM_TIMER 858 help 859 This option allows to run Linux as guest in a Jailhouse non-root 860 cell. You can leave this option disabled if you only want to start 861 Jailhouse and run Linux afterwards in the root cell. 862 863config ACRN_GUEST 864 bool "ACRN Guest support" 865 depends on X86_64 866 select X86_HV_CALLBACK_VECTOR 867 help 868 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 869 a flexible, lightweight reference open-source hypervisor, built with 870 real-time and safety-criticality in mind. It is built for embedded 871 IOT with small footprint and real-time features. More details can be 872 found in https://projectacrn.org/. 873 874endif #HYPERVISOR_GUEST 875 876source "arch/x86/Kconfig.cpu" 877 878config HPET_TIMER 879 def_bool X86_64 880 prompt "HPET Timer Support" if X86_32 881 help 882 Use the IA-PC HPET (High Precision Event Timer) to manage 883 time in preference to the PIT and RTC, if a HPET is 884 present. 885 HPET is the next generation timer replacing legacy 8254s. 886 The HPET provides a stable time base on SMP 887 systems, unlike the TSC, but it is more expensive to access, 888 as it is off-chip. The interface used is documented 889 in the HPET spec, revision 1. 890 891 You can safely choose Y here. However, HPET will only be 892 activated if the platform and the BIOS support this feature. 893 Otherwise the 8254 will be used for timing services. 894 895 Choose N to continue using the legacy 8254 timer. 896 897config HPET_EMULATE_RTC 898 def_bool y 899 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 900 901# Mark as expert because too many people got it wrong. 902# The code disables itself when not needed. 903config DMI 904 default y 905 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 906 bool "Enable DMI scanning" if EXPERT 907 help 908 Enabled scanning of DMI to identify machine quirks. Say Y 909 here unless you have verified that your setup is not 910 affected by entries in the DMI blacklist. Required by PNP 911 BIOS code. 912 913config GART_IOMMU 914 bool "Old AMD GART IOMMU support" 915 select DMA_OPS 916 select IOMMU_HELPER 917 select SWIOTLB 918 depends on X86_64 && PCI && AMD_NB 919 help 920 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 921 GART based hardware IOMMUs. 922 923 The GART supports full DMA access for devices with 32-bit access 924 limitations, on systems with more than 3 GB. This is usually needed 925 for USB, sound, many IDE/SATA chipsets and some other devices. 926 927 Newer systems typically have a modern AMD IOMMU, supported via 928 the CONFIG_AMD_IOMMU=y config option. 929 930 In normal configurations this driver is only active when needed: 931 there's more than 3 GB of memory and the system contains a 932 32-bit limited device. 933 934 If unsure, say Y. 935 936config MAXSMP 937 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 938 depends on X86_64 && SMP && DEBUG_KERNEL 939 select CPUMASK_OFFSTACK 940 help 941 Enable maximum number of CPUS and NUMA Nodes for this architecture. 942 If unsure, say N. 943 944# 945# The maximum number of CPUs supported: 946# 947# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 948# and which can be configured interactively in the 949# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 950# 951# The ranges are different on 32-bit and 64-bit kernels, depending on 952# hardware capabilities and scalability features of the kernel. 953# 954# ( If MAXSMP is enabled we just use the highest possible value and disable 955# interactive configuration. ) 956# 957 958config NR_CPUS_RANGE_BEGIN 959 int 960 default NR_CPUS_RANGE_END if MAXSMP 961 default 1 if !SMP 962 default 2 963 964config NR_CPUS_RANGE_END 965 int 966 depends on X86_32 967 default 64 if SMP && X86_BIGSMP 968 default 8 if SMP && !X86_BIGSMP 969 default 1 if !SMP 970 971config NR_CPUS_RANGE_END 972 int 973 depends on X86_64 974 default 8192 if SMP && CPUMASK_OFFSTACK 975 default 512 if SMP && !CPUMASK_OFFSTACK 976 default 1 if !SMP 977 978config NR_CPUS_DEFAULT 979 int 980 depends on X86_32 981 default 32 if X86_BIGSMP 982 default 8 if SMP 983 default 1 if !SMP 984 985config NR_CPUS_DEFAULT 986 int 987 depends on X86_64 988 default 8192 if MAXSMP 989 default 64 if SMP 990 default 1 if !SMP 991 992config NR_CPUS 993 int "Maximum number of CPUs" if SMP && !MAXSMP 994 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 995 default NR_CPUS_DEFAULT 996 help 997 This allows you to specify the maximum number of CPUs which this 998 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 999 supported value is 8192, otherwise the maximum value is 512. The 1000 minimum value which makes sense is 2. 1001 1002 This is purely to save memory: each supported CPU adds about 8KB 1003 to the kernel image. 1004 1005config SCHED_SMT 1006 def_bool y if SMP 1007 1008config SCHED_MC 1009 def_bool y 1010 prompt "Multi-core scheduler support" 1011 depends on SMP 1012 help 1013 Multi-core scheduler support improves the CPU scheduler's decision 1014 making when dealing with multi-core CPU chips at a cost of slightly 1015 increased overhead in some places. If unsure say N here. 1016 1017config SCHED_MC_PRIO 1018 bool "CPU core priorities scheduler support" 1019 depends on SCHED_MC && CPU_SUP_INTEL 1020 select X86_INTEL_PSTATE 1021 select CPU_FREQ 1022 default y 1023 help 1024 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1025 core ordering determined at manufacturing time, which allows 1026 certain cores to reach higher turbo frequencies (when running 1027 single threaded workloads) than others. 1028 1029 Enabling this kernel feature teaches the scheduler about 1030 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1031 scheduler's CPU selection logic accordingly, so that higher 1032 overall system performance can be achieved. 1033 1034 This feature will have no effect on CPUs without this feature. 1035 1036 If unsure say Y here. 1037 1038config UP_LATE_INIT 1039 def_bool y 1040 depends on !SMP && X86_LOCAL_APIC 1041 1042config X86_UP_APIC 1043 bool "Local APIC support on uniprocessors" if !PCI_MSI 1044 default PCI_MSI 1045 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1046 help 1047 A local APIC (Advanced Programmable Interrupt Controller) is an 1048 integrated interrupt controller in the CPU. If you have a single-CPU 1049 system which has a processor with a local APIC, you can say Y here to 1050 enable and use it. If you say Y here even though your machine doesn't 1051 have a local APIC, then the kernel will still run with no slowdown at 1052 all. The local APIC supports CPU-generated self-interrupts (timer, 1053 performance counters), and the NMI watchdog which detects hard 1054 lockups. 1055 1056config X86_UP_IOAPIC 1057 bool "IO-APIC support on uniprocessors" 1058 depends on X86_UP_APIC 1059 help 1060 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1061 SMP-capable replacement for PC-style interrupt controllers. Most 1062 SMP systems and many recent uniprocessor systems have one. 1063 1064 If you have a single-CPU system with an IO-APIC, you can say Y here 1065 to use it. If you say Y here even though your machine doesn't have 1066 an IO-APIC, then the kernel will still run with no slowdown at all. 1067 1068config X86_LOCAL_APIC 1069 def_bool y 1070 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1071 select IRQ_DOMAIN_HIERARCHY 1072 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1073 1074config X86_IO_APIC 1075 def_bool y 1076 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1077 1078config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1079 bool "Reroute for broken boot IRQs" 1080 depends on X86_IO_APIC 1081 help 1082 This option enables a workaround that fixes a source of 1083 spurious interrupts. This is recommended when threaded 1084 interrupt handling is used on systems where the generation of 1085 superfluous "boot interrupts" cannot be disabled. 1086 1087 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1088 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1089 kernel does during interrupt handling). On chipsets where this 1090 boot IRQ generation cannot be disabled, this workaround keeps 1091 the original IRQ line masked so that only the equivalent "boot 1092 IRQ" is delivered to the CPUs. The workaround also tells the 1093 kernel to set up the IRQ handler on the boot IRQ line. In this 1094 way only one interrupt is delivered to the kernel. Otherwise 1095 the spurious second interrupt may cause the kernel to bring 1096 down (vital) interrupt lines. 1097 1098 Only affects "broken" chipsets. Interrupt sharing may be 1099 increased on these systems. 1100 1101config X86_MCE 1102 bool "Machine Check / overheating reporting" 1103 select GENERIC_ALLOCATOR 1104 default y 1105 help 1106 Machine Check support allows the processor to notify the 1107 kernel if it detects a problem (e.g. overheating, data corruption). 1108 The action the kernel takes depends on the severity of the problem, 1109 ranging from warning messages to halting the machine. 1110 1111config X86_MCELOG_LEGACY 1112 bool "Support for deprecated /dev/mcelog character device" 1113 depends on X86_MCE 1114 help 1115 Enable support for /dev/mcelog which is needed by the old mcelog 1116 userspace logging daemon. Consider switching to the new generation 1117 rasdaemon solution. 1118 1119config X86_MCE_INTEL 1120 def_bool y 1121 prompt "Intel MCE features" 1122 depends on X86_MCE && X86_LOCAL_APIC 1123 help 1124 Additional support for intel specific MCE features such as 1125 the thermal monitor. 1126 1127config X86_MCE_AMD 1128 def_bool y 1129 prompt "AMD MCE features" 1130 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1131 help 1132 Additional support for AMD specific MCE features such as 1133 the DRAM Error Threshold. 1134 1135config X86_ANCIENT_MCE 1136 bool "Support for old Pentium 5 / WinChip machine checks" 1137 depends on X86_32 && X86_MCE 1138 help 1139 Include support for machine check handling on old Pentium 5 or WinChip 1140 systems. These typically need to be enabled explicitly on the command 1141 line. 1142 1143config X86_MCE_THRESHOLD 1144 depends on X86_MCE_AMD || X86_MCE_INTEL 1145 def_bool y 1146 1147config X86_MCE_INJECT 1148 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1149 tristate "Machine check injector support" 1150 help 1151 Provide support for injecting machine checks for testing purposes. 1152 If you don't know what a machine check is and you don't do kernel 1153 QA it is safe to say n. 1154 1155source "arch/x86/events/Kconfig" 1156 1157config X86_LEGACY_VM86 1158 bool "Legacy VM86 support" 1159 depends on X86_32 1160 help 1161 This option allows user programs to put the CPU into V8086 1162 mode, which is an 80286-era approximation of 16-bit real mode. 1163 1164 Some very old versions of X and/or vbetool require this option 1165 for user mode setting. Similarly, DOSEMU will use it if 1166 available to accelerate real mode DOS programs. However, any 1167 recent version of DOSEMU, X, or vbetool should be fully 1168 functional even without kernel VM86 support, as they will all 1169 fall back to software emulation. Nevertheless, if you are using 1170 a 16-bit DOS program where 16-bit performance matters, vm86 1171 mode might be faster than emulation and you might want to 1172 enable this option. 1173 1174 Note that any app that works on a 64-bit kernel is unlikely to 1175 need this option, as 64-bit kernels don't, and can't, support 1176 V8086 mode. This option is also unrelated to 16-bit protected 1177 mode and is not needed to run most 16-bit programs under Wine. 1178 1179 Enabling this option increases the complexity of the kernel 1180 and slows down exception handling a tiny bit. 1181 1182 If unsure, say N here. 1183 1184config VM86 1185 bool 1186 default X86_LEGACY_VM86 1187 1188config X86_16BIT 1189 bool "Enable support for 16-bit segments" if EXPERT 1190 default y 1191 depends on MODIFY_LDT_SYSCALL 1192 help 1193 This option is required by programs like Wine to run 16-bit 1194 protected mode legacy code on x86 processors. Disabling 1195 this option saves about 300 bytes on i386, or around 6K text 1196 plus 16K runtime memory on x86-64, 1197 1198config X86_ESPFIX32 1199 def_bool y 1200 depends on X86_16BIT && X86_32 1201 1202config X86_ESPFIX64 1203 def_bool y 1204 depends on X86_16BIT && X86_64 1205 1206config X86_VSYSCALL_EMULATION 1207 bool "Enable vsyscall emulation" if EXPERT 1208 default y 1209 depends on X86_64 1210 help 1211 This enables emulation of the legacy vsyscall page. Disabling 1212 it is roughly equivalent to booting with vsyscall=none, except 1213 that it will also disable the helpful warning if a program 1214 tries to use a vsyscall. With this option set to N, offending 1215 programs will just segfault, citing addresses of the form 1216 0xffffffffff600?00. 1217 1218 This option is required by many programs built before 2013, and 1219 care should be used even with newer programs if set to N. 1220 1221 Disabling this option saves about 7K of kernel size and 1222 possibly 4K of additional runtime pagetable memory. 1223 1224config X86_IOPL_IOPERM 1225 bool "IOPERM and IOPL Emulation" 1226 default y 1227 help 1228 This enables the ioperm() and iopl() syscalls which are necessary 1229 for legacy applications. 1230 1231 Legacy IOPL support is an overbroad mechanism which allows user 1232 space aside of accessing all 65536 I/O ports also to disable 1233 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1234 capabilities and permission from potentially active security 1235 modules. 1236 1237 The emulation restricts the functionality of the syscall to 1238 only allowing the full range I/O port access, but prevents the 1239 ability to disable interrupts from user space which would be 1240 granted if the hardware IOPL mechanism would be used. 1241 1242config TOSHIBA 1243 tristate "Toshiba Laptop support" 1244 depends on X86_32 1245 help 1246 This adds a driver to safely access the System Management Mode of 1247 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1248 not work on models with a Phoenix BIOS. The System Management Mode 1249 is used to set the BIOS and power saving options on Toshiba portables. 1250 1251 For information on utilities to make use of this driver see the 1252 Toshiba Linux utilities web site at: 1253 <http://www.buzzard.org.uk/toshiba/>. 1254 1255 Say Y if you intend to run this kernel on a Toshiba portable. 1256 Say N otherwise. 1257 1258config I8K 1259 tristate "Dell i8k legacy laptop support" 1260 select HWMON 1261 select SENSORS_DELL_SMM 1262 help 1263 This option enables legacy /proc/i8k userspace interface in hwmon 1264 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1265 temperature and allows controlling fan speeds of Dell laptops via 1266 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1267 it reports also power and hotkey status. For fan speed control is 1268 needed userspace package i8kutils. 1269 1270 Say Y if you intend to run this kernel on old Dell laptops or want to 1271 use userspace package i8kutils. 1272 Say N otherwise. 1273 1274config X86_REBOOTFIXUPS 1275 bool "Enable X86 board specific fixups for reboot" 1276 depends on X86_32 1277 help 1278 This enables chipset and/or board specific fixups to be done 1279 in order to get reboot to work correctly. This is only needed on 1280 some combinations of hardware and BIOS. The symptom, for which 1281 this config is intended, is when reboot ends with a stalled/hung 1282 system. 1283 1284 Currently, the only fixup is for the Geode machines using 1285 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1286 1287 Say Y if you want to enable the fixup. Currently, it's safe to 1288 enable this option even if you don't need it. 1289 Say N otherwise. 1290 1291config MICROCODE 1292 bool "CPU microcode loading support" 1293 default y 1294 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1295 help 1296 If you say Y here, you will be able to update the microcode on 1297 Intel and AMD processors. The Intel support is for the IA32 family, 1298 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1299 AMD support is for families 0x10 and later. You will obviously need 1300 the actual microcode binary data itself which is not shipped with 1301 the Linux kernel. 1302 1303 The preferred method to load microcode from a detached initrd is described 1304 in Documentation/x86/microcode.rst. For that you need to enable 1305 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1306 initrd for microcode blobs. 1307 1308 In addition, you can build the microcode into the kernel. For that you 1309 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1310 config option. 1311 1312config MICROCODE_INTEL 1313 bool "Intel microcode loading support" 1314 depends on MICROCODE 1315 default MICROCODE 1316 help 1317 This options enables microcode patch loading support for Intel 1318 processors. 1319 1320 For the current Intel microcode data package go to 1321 <https://downloadcenter.intel.com> and search for 1322 'Linux Processor Microcode Data File'. 1323 1324config MICROCODE_AMD 1325 bool "AMD microcode loading support" 1326 depends on MICROCODE 1327 help 1328 If you select this option, microcode patch loading support for AMD 1329 processors will be enabled. 1330 1331config MICROCODE_OLD_INTERFACE 1332 bool "Ancient loading interface (DEPRECATED)" 1333 default n 1334 depends on MICROCODE 1335 help 1336 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1337 which was used by userspace tools like iucode_tool and microcode.ctl. 1338 It is inadequate because it runs too late to be able to properly 1339 load microcode on a machine and it needs special tools. Instead, you 1340 should've switched to the early loading method with the initrd or 1341 builtin microcode by now: Documentation/x86/microcode.rst 1342 1343config X86_MSR 1344 tristate "/dev/cpu/*/msr - Model-specific register support" 1345 help 1346 This device gives privileged processes access to the x86 1347 Model-Specific Registers (MSRs). It is a character device with 1348 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1349 MSR accesses are directed to a specific CPU on multi-processor 1350 systems. 1351 1352config X86_CPUID 1353 tristate "/dev/cpu/*/cpuid - CPU information support" 1354 help 1355 This device gives processes access to the x86 CPUID instruction to 1356 be executed on a specific processor. It is a character device 1357 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1358 /dev/cpu/31/cpuid. 1359 1360choice 1361 prompt "High Memory Support" 1362 default HIGHMEM4G 1363 depends on X86_32 1364 1365config NOHIGHMEM 1366 bool "off" 1367 help 1368 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1369 However, the address space of 32-bit x86 processors is only 4 1370 Gigabytes large. That means that, if you have a large amount of 1371 physical memory, not all of it can be "permanently mapped" by the 1372 kernel. The physical memory that's not permanently mapped is called 1373 "high memory". 1374 1375 If you are compiling a kernel which will never run on a machine with 1376 more than 1 Gigabyte total physical RAM, answer "off" here (default 1377 choice and suitable for most users). This will result in a "3GB/1GB" 1378 split: 3GB are mapped so that each process sees a 3GB virtual memory 1379 space and the remaining part of the 4GB virtual memory space is used 1380 by the kernel to permanently map as much physical memory as 1381 possible. 1382 1383 If the machine has between 1 and 4 Gigabytes physical RAM, then 1384 answer "4GB" here. 1385 1386 If more than 4 Gigabytes is used then answer "64GB" here. This 1387 selection turns Intel PAE (Physical Address Extension) mode on. 1388 PAE implements 3-level paging on IA32 processors. PAE is fully 1389 supported by Linux, PAE mode is implemented on all recent Intel 1390 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1391 then the kernel will not boot on CPUs that don't support PAE! 1392 1393 The actual amount of total physical memory will either be 1394 auto detected or can be forced by using a kernel command line option 1395 such as "mem=256M". (Try "man bootparam" or see the documentation of 1396 your boot loader (lilo or loadlin) about how to pass options to the 1397 kernel at boot time.) 1398 1399 If unsure, say "off". 1400 1401config HIGHMEM4G 1402 bool "4GB" 1403 help 1404 Select this if you have a 32-bit processor and between 1 and 4 1405 gigabytes of physical RAM. 1406 1407config HIGHMEM64G 1408 bool "64GB" 1409 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1410 select X86_PAE 1411 help 1412 Select this if you have a 32-bit processor and more than 4 1413 gigabytes of physical RAM. 1414 1415endchoice 1416 1417choice 1418 prompt "Memory split" if EXPERT 1419 default VMSPLIT_3G 1420 depends on X86_32 1421 help 1422 Select the desired split between kernel and user memory. 1423 1424 If the address range available to the kernel is less than the 1425 physical memory installed, the remaining memory will be available 1426 as "high memory". Accessing high memory is a little more costly 1427 than low memory, as it needs to be mapped into the kernel first. 1428 Note that increasing the kernel address space limits the range 1429 available to user programs, making the address space there 1430 tighter. Selecting anything other than the default 3G/1G split 1431 will also likely make your kernel incompatible with binary-only 1432 kernel modules. 1433 1434 If you are not absolutely sure what you are doing, leave this 1435 option alone! 1436 1437 config VMSPLIT_3G 1438 bool "3G/1G user/kernel split" 1439 config VMSPLIT_3G_OPT 1440 depends on !X86_PAE 1441 bool "3G/1G user/kernel split (for full 1G low memory)" 1442 config VMSPLIT_2G 1443 bool "2G/2G user/kernel split" 1444 config VMSPLIT_2G_OPT 1445 depends on !X86_PAE 1446 bool "2G/2G user/kernel split (for full 2G low memory)" 1447 config VMSPLIT_1G 1448 bool "1G/3G user/kernel split" 1449endchoice 1450 1451config PAGE_OFFSET 1452 hex 1453 default 0xB0000000 if VMSPLIT_3G_OPT 1454 default 0x80000000 if VMSPLIT_2G 1455 default 0x78000000 if VMSPLIT_2G_OPT 1456 default 0x40000000 if VMSPLIT_1G 1457 default 0xC0000000 1458 depends on X86_32 1459 1460config HIGHMEM 1461 def_bool y 1462 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1463 1464config X86_PAE 1465 bool "PAE (Physical Address Extension) Support" 1466 depends on X86_32 && !HIGHMEM4G 1467 select PHYS_ADDR_T_64BIT 1468 select SWIOTLB 1469 help 1470 PAE is required for NX support, and furthermore enables 1471 larger swapspace support for non-overcommit purposes. It 1472 has the cost of more pagetable lookup overhead, and also 1473 consumes more pagetable space per process. 1474 1475config X86_5LEVEL 1476 bool "Enable 5-level page tables support" 1477 default y 1478 select DYNAMIC_MEMORY_LAYOUT 1479 select SPARSEMEM_VMEMMAP 1480 depends on X86_64 1481 help 1482 5-level paging enables access to larger address space: 1483 upto 128 PiB of virtual address space and 4 PiB of 1484 physical address space. 1485 1486 It will be supported by future Intel CPUs. 1487 1488 A kernel with the option enabled can be booted on machines that 1489 support 4- or 5-level paging. 1490 1491 See Documentation/x86/x86_64/5level-paging.rst for more 1492 information. 1493 1494 Say N if unsure. 1495 1496config X86_DIRECT_GBPAGES 1497 def_bool y 1498 depends on X86_64 1499 help 1500 Certain kernel features effectively disable kernel 1501 linear 1 GB mappings (even if the CPU otherwise 1502 supports them), so don't confuse the user by printing 1503 that we have them enabled. 1504 1505config X86_CPA_STATISTICS 1506 bool "Enable statistic for Change Page Attribute" 1507 depends on DEBUG_FS 1508 help 1509 Expose statistics about the Change Page Attribute mechanism, which 1510 helps to determine the effectiveness of preserving large and huge 1511 page mappings when mapping protections are changed. 1512 1513config AMD_MEM_ENCRYPT 1514 bool "AMD Secure Memory Encryption (SME) support" 1515 depends on X86_64 && CPU_SUP_AMD 1516 select DMA_COHERENT_POOL 1517 select DYNAMIC_PHYSICAL_MASK 1518 select ARCH_USE_MEMREMAP_PROT 1519 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1520 select INSTRUCTION_DECODER 1521 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 1522 help 1523 Say yes to enable support for the encryption of system memory. 1524 This requires an AMD processor that supports Secure Memory 1525 Encryption (SME). 1526 1527config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1528 bool "Activate AMD Secure Memory Encryption (SME) by default" 1529 default y 1530 depends on AMD_MEM_ENCRYPT 1531 help 1532 Say yes to have system memory encrypted by default if running on 1533 an AMD processor that supports Secure Memory Encryption (SME). 1534 1535 If set to Y, then the encryption of system memory can be 1536 deactivated with the mem_encrypt=off command line option. 1537 1538 If set to N, then the encryption of system memory can be 1539 activated with the mem_encrypt=on command line option. 1540 1541# Common NUMA Features 1542config NUMA 1543 bool "NUMA Memory Allocation and Scheduler Support" 1544 depends on SMP 1545 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1546 default y if X86_BIGSMP 1547 help 1548 Enable NUMA (Non-Uniform Memory Access) support. 1549 1550 The kernel will try to allocate memory used by a CPU on the 1551 local memory controller of the CPU and add some more 1552 NUMA awareness to the kernel. 1553 1554 For 64-bit this is recommended if the system is Intel Core i7 1555 (or later), AMD Opteron, or EM64T NUMA. 1556 1557 For 32-bit this is only needed if you boot a 32-bit 1558 kernel on a 64-bit NUMA platform. 1559 1560 Otherwise, you should say N. 1561 1562config AMD_NUMA 1563 def_bool y 1564 prompt "Old style AMD Opteron NUMA detection" 1565 depends on X86_64 && NUMA && PCI 1566 help 1567 Enable AMD NUMA node topology detection. You should say Y here if 1568 you have a multi processor AMD system. This uses an old method to 1569 read the NUMA configuration directly from the builtin Northbridge 1570 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1571 which also takes priority if both are compiled in. 1572 1573config X86_64_ACPI_NUMA 1574 def_bool y 1575 prompt "ACPI NUMA detection" 1576 depends on X86_64 && NUMA && ACPI && PCI 1577 select ACPI_NUMA 1578 help 1579 Enable ACPI SRAT based node topology detection. 1580 1581config NUMA_EMU 1582 bool "NUMA emulation" 1583 depends on NUMA 1584 help 1585 Enable NUMA emulation. A flat machine will be split 1586 into virtual nodes when booted with "numa=fake=N", where N is the 1587 number of nodes. This is only useful for debugging. 1588 1589config NODES_SHIFT 1590 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1591 range 1 10 1592 default "10" if MAXSMP 1593 default "6" if X86_64 1594 default "3" 1595 depends on NEED_MULTIPLE_NODES 1596 help 1597 Specify the maximum number of NUMA Nodes available on the target 1598 system. Increases memory reserved to accommodate various tables. 1599 1600config ARCH_FLATMEM_ENABLE 1601 def_bool y 1602 depends on X86_32 && !NUMA 1603 1604config ARCH_SPARSEMEM_ENABLE 1605 def_bool y 1606 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1607 select SPARSEMEM_STATIC if X86_32 1608 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1609 1610config ARCH_SPARSEMEM_DEFAULT 1611 def_bool X86_64 || (NUMA && X86_32) 1612 1613config ARCH_SELECT_MEMORY_MODEL 1614 def_bool y 1615 depends on ARCH_SPARSEMEM_ENABLE 1616 1617config ARCH_MEMORY_PROBE 1618 bool "Enable sysfs memory/probe interface" 1619 depends on X86_64 && MEMORY_HOTPLUG 1620 help 1621 This option enables a sysfs memory/probe interface for testing. 1622 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1623 If you are unsure how to answer this question, answer N. 1624 1625config ARCH_PROC_KCORE_TEXT 1626 def_bool y 1627 depends on X86_64 && PROC_KCORE 1628 1629config ILLEGAL_POINTER_VALUE 1630 hex 1631 default 0 if X86_32 1632 default 0xdead000000000000 if X86_64 1633 1634config X86_PMEM_LEGACY_DEVICE 1635 bool 1636 1637config X86_PMEM_LEGACY 1638 tristate "Support non-standard NVDIMMs and ADR protected memory" 1639 depends on PHYS_ADDR_T_64BIT 1640 depends on BLK_DEV 1641 select X86_PMEM_LEGACY_DEVICE 1642 select NUMA_KEEP_MEMINFO if NUMA 1643 select LIBNVDIMM 1644 help 1645 Treat memory marked using the non-standard e820 type of 12 as used 1646 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1647 The kernel will offer these regions to the 'pmem' driver so 1648 they can be used for persistent storage. 1649 1650 Say Y if unsure. 1651 1652config HIGHPTE 1653 bool "Allocate 3rd-level pagetables from highmem" 1654 depends on HIGHMEM 1655 help 1656 The VM uses one page table entry for each page of physical memory. 1657 For systems with a lot of RAM, this can be wasteful of precious 1658 low memory. Setting this option will put user-space page table 1659 entries in high memory. 1660 1661config X86_CHECK_BIOS_CORRUPTION 1662 bool "Check for low memory corruption" 1663 help 1664 Periodically check for memory corruption in low memory, which 1665 is suspected to be caused by BIOS. Even when enabled in the 1666 configuration, it is disabled at runtime. Enable it by 1667 setting "memory_corruption_check=1" on the kernel command 1668 line. By default it scans the low 64k of memory every 60 1669 seconds; see the memory_corruption_check_size and 1670 memory_corruption_check_period parameters in 1671 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1672 1673 When enabled with the default parameters, this option has 1674 almost no overhead, as it reserves a relatively small amount 1675 of memory and scans it infrequently. It both detects corruption 1676 and prevents it from affecting the running system. 1677 1678 It is, however, intended as a diagnostic tool; if repeatable 1679 BIOS-originated corruption always affects the same memory, 1680 you can use memmap= to prevent the kernel from using that 1681 memory. 1682 1683config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1684 bool "Set the default setting of memory_corruption_check" 1685 depends on X86_CHECK_BIOS_CORRUPTION 1686 default y 1687 help 1688 Set whether the default state of memory_corruption_check is 1689 on or off. 1690 1691config X86_RESERVE_LOW 1692 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1693 default 64 1694 range 4 640 1695 help 1696 Specify the amount of low memory to reserve for the BIOS. 1697 1698 The first page contains BIOS data structures that the kernel 1699 must not use, so that page must always be reserved. 1700 1701 By default we reserve the first 64K of physical RAM, as a 1702 number of BIOSes are known to corrupt that memory range 1703 during events such as suspend/resume or monitor cable 1704 insertion, so it must not be used by the kernel. 1705 1706 You can set this to 4 if you are absolutely sure that you 1707 trust the BIOS to get all its memory reservations and usages 1708 right. If you know your BIOS have problems beyond the 1709 default 64K area, you can set this to 640 to avoid using the 1710 entire low memory range. 1711 1712 If you have doubts about the BIOS (e.g. suspend/resume does 1713 not work or there's kernel crashes after certain hardware 1714 hotplug events) then you might want to enable 1715 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1716 typical corruption patterns. 1717 1718 Leave this to the default value of 64 if you are unsure. 1719 1720config MATH_EMULATION 1721 bool 1722 depends on MODIFY_LDT_SYSCALL 1723 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1724 help 1725 Linux can emulate a math coprocessor (used for floating point 1726 operations) if you don't have one. 486DX and Pentium processors have 1727 a math coprocessor built in, 486SX and 386 do not, unless you added 1728 a 487DX or 387, respectively. (The messages during boot time can 1729 give you some hints here ["man dmesg"].) Everyone needs either a 1730 coprocessor or this emulation. 1731 1732 If you don't have a math coprocessor, you need to say Y here; if you 1733 say Y here even though you have a coprocessor, the coprocessor will 1734 be used nevertheless. (This behavior can be changed with the kernel 1735 command line option "no387", which comes handy if your coprocessor 1736 is broken. Try "man bootparam" or see the documentation of your boot 1737 loader (lilo or loadlin) about how to pass options to the kernel at 1738 boot time.) This means that it is a good idea to say Y here if you 1739 intend to use this kernel on different machines. 1740 1741 More information about the internals of the Linux math coprocessor 1742 emulation can be found in <file:arch/x86/math-emu/README>. 1743 1744 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1745 kernel, it won't hurt. 1746 1747config MTRR 1748 def_bool y 1749 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1750 help 1751 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1752 the Memory Type Range Registers (MTRRs) may be used to control 1753 processor access to memory ranges. This is most useful if you have 1754 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1755 allows bus write transfers to be combined into a larger transfer 1756 before bursting over the PCI/AGP bus. This can increase performance 1757 of image write operations 2.5 times or more. Saying Y here creates a 1758 /proc/mtrr file which may be used to manipulate your processor's 1759 MTRRs. Typically the X server should use this. 1760 1761 This code has a reasonably generic interface so that similar 1762 control registers on other processors can be easily supported 1763 as well: 1764 1765 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1766 Registers (ARRs) which provide a similar functionality to MTRRs. For 1767 these, the ARRs are used to emulate the MTRRs. 1768 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1769 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1770 write-combining. All of these processors are supported by this code 1771 and it makes sense to say Y here if you have one of them. 1772 1773 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1774 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1775 can lead to all sorts of problems, so it's good to say Y here. 1776 1777 You can safely say Y even if your machine doesn't have MTRRs, you'll 1778 just add about 9 KB to your kernel. 1779 1780 See <file:Documentation/x86/mtrr.rst> for more information. 1781 1782config MTRR_SANITIZER 1783 def_bool y 1784 prompt "MTRR cleanup support" 1785 depends on MTRR 1786 help 1787 Convert MTRR layout from continuous to discrete, so X drivers can 1788 add writeback entries. 1789 1790 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1791 The largest mtrr entry size for a continuous block can be set with 1792 mtrr_chunk_size. 1793 1794 If unsure, say Y. 1795 1796config MTRR_SANITIZER_ENABLE_DEFAULT 1797 int "MTRR cleanup enable value (0-1)" 1798 range 0 1 1799 default "0" 1800 depends on MTRR_SANITIZER 1801 help 1802 Enable mtrr cleanup default value 1803 1804config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1805 int "MTRR cleanup spare reg num (0-7)" 1806 range 0 7 1807 default "1" 1808 depends on MTRR_SANITIZER 1809 help 1810 mtrr cleanup spare entries default, it can be changed via 1811 mtrr_spare_reg_nr=N on the kernel command line. 1812 1813config X86_PAT 1814 def_bool y 1815 prompt "x86 PAT support" if EXPERT 1816 depends on MTRR 1817 help 1818 Use PAT attributes to setup page level cache control. 1819 1820 PATs are the modern equivalents of MTRRs and are much more 1821 flexible than MTRRs. 1822 1823 Say N here if you see bootup problems (boot crash, boot hang, 1824 spontaneous reboots) or a non-working video driver. 1825 1826 If unsure, say Y. 1827 1828config ARCH_USES_PG_UNCACHED 1829 def_bool y 1830 depends on X86_PAT 1831 1832config ARCH_RANDOM 1833 def_bool y 1834 prompt "x86 architectural random number generator" if EXPERT 1835 help 1836 Enable the x86 architectural RDRAND instruction 1837 (Intel Bull Mountain technology) to generate random numbers. 1838 If supported, this is a high bandwidth, cryptographically 1839 secure hardware random number generator. 1840 1841config X86_SMAP 1842 def_bool y 1843 prompt "Supervisor Mode Access Prevention" if EXPERT 1844 help 1845 Supervisor Mode Access Prevention (SMAP) is a security 1846 feature in newer Intel processors. There is a small 1847 performance cost if this enabled and turned on; there is 1848 also a small increase in the kernel size if this is enabled. 1849 1850 If unsure, say Y. 1851 1852config X86_UMIP 1853 def_bool y 1854 prompt "User Mode Instruction Prevention" if EXPERT 1855 help 1856 User Mode Instruction Prevention (UMIP) is a security feature in 1857 some x86 processors. If enabled, a general protection fault is 1858 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1859 executed in user mode. These instructions unnecessarily expose 1860 information about the hardware state. 1861 1862 The vast majority of applications do not use these instructions. 1863 For the very few that do, software emulation is provided in 1864 specific cases in protected and virtual-8086 modes. Emulated 1865 results are dummy. 1866 1867config X86_INTEL_MEMORY_PROTECTION_KEYS 1868 prompt "Memory Protection Keys" 1869 def_bool y 1870 # Note: only available in 64-bit mode 1871 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1872 select ARCH_USES_HIGH_VMA_FLAGS 1873 select ARCH_HAS_PKEYS 1874 help 1875 Memory Protection Keys provides a mechanism for enforcing 1876 page-based protections, but without requiring modification of the 1877 page tables when an application changes protection domains. 1878 1879 For details, see Documentation/core-api/protection-keys.rst 1880 1881 If unsure, say y. 1882 1883choice 1884 prompt "TSX enable mode" 1885 depends on CPU_SUP_INTEL 1886 default X86_INTEL_TSX_MODE_OFF 1887 help 1888 Intel's TSX (Transactional Synchronization Extensions) feature 1889 allows to optimize locking protocols through lock elision which 1890 can lead to a noticeable performance boost. 1891 1892 On the other hand it has been shown that TSX can be exploited 1893 to form side channel attacks (e.g. TAA) and chances are there 1894 will be more of those attacks discovered in the future. 1895 1896 Therefore TSX is not enabled by default (aka tsx=off). An admin 1897 might override this decision by tsx=on the command line parameter. 1898 Even with TSX enabled, the kernel will attempt to enable the best 1899 possible TAA mitigation setting depending on the microcode available 1900 for the particular machine. 1901 1902 This option allows to set the default tsx mode between tsx=on, =off 1903 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1904 details. 1905 1906 Say off if not sure, auto if TSX is in use but it should be used on safe 1907 platforms or on if TSX is in use and the security aspect of tsx is not 1908 relevant. 1909 1910config X86_INTEL_TSX_MODE_OFF 1911 bool "off" 1912 help 1913 TSX is disabled if possible - equals to tsx=off command line parameter. 1914 1915config X86_INTEL_TSX_MODE_ON 1916 bool "on" 1917 help 1918 TSX is always enabled on TSX capable HW - equals the tsx=on command 1919 line parameter. 1920 1921config X86_INTEL_TSX_MODE_AUTO 1922 bool "auto" 1923 help 1924 TSX is enabled on TSX capable HW that is believed to be safe against 1925 side channel attacks- equals the tsx=auto command line parameter. 1926endchoice 1927 1928config X86_SGX 1929 bool "Software Guard eXtensions (SGX)" 1930 depends on X86_64 && CPU_SUP_INTEL 1931 depends on CRYPTO=y 1932 depends on CRYPTO_SHA256=y 1933 select SRCU 1934 select MMU_NOTIFIER 1935 select NUMA_KEEP_MEMINFO if NUMA 1936 help 1937 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1938 that can be used by applications to set aside private regions of code 1939 and data, referred to as enclaves. An enclave's private memory can 1940 only be accessed by code running within the enclave. Accesses from 1941 outside the enclave, including other enclaves, are disallowed by 1942 hardware. 1943 1944 If unsure, say N. 1945 1946config EFI 1947 bool "EFI runtime service support" 1948 depends on ACPI 1949 select UCS2_STRING 1950 select EFI_RUNTIME_WRAPPERS 1951 help 1952 This enables the kernel to use EFI runtime services that are 1953 available (such as the EFI variable services). 1954 1955 This option is only useful on systems that have EFI firmware. 1956 In addition, you should use the latest ELILO loader available 1957 at <http://elilo.sourceforge.net> in order to take advantage 1958 of EFI runtime services. However, even with this option, the 1959 resultant kernel should continue to boot on existing non-EFI 1960 platforms. 1961 1962config EFI_STUB 1963 bool "EFI stub support" 1964 depends on EFI && !X86_USE_3DNOW 1965 depends on $(cc-option,-mabi=ms) || X86_32 1966 select RELOCATABLE 1967 help 1968 This kernel feature allows a bzImage to be loaded directly 1969 by EFI firmware without the use of a bootloader. 1970 1971 See Documentation/admin-guide/efi-stub.rst for more information. 1972 1973config EFI_MIXED 1974 bool "EFI mixed-mode support" 1975 depends on EFI_STUB && X86_64 1976 help 1977 Enabling this feature allows a 64-bit kernel to be booted 1978 on a 32-bit firmware, provided that your CPU supports 64-bit 1979 mode. 1980 1981 Note that it is not possible to boot a mixed-mode enabled 1982 kernel via the EFI boot stub - a bootloader that supports 1983 the EFI handover protocol must be used. 1984 1985 If unsure, say N. 1986 1987source "kernel/Kconfig.hz" 1988 1989config KEXEC 1990 bool "kexec system call" 1991 select KEXEC_CORE 1992 help 1993 kexec is a system call that implements the ability to shutdown your 1994 current kernel, and to start another kernel. It is like a reboot 1995 but it is independent of the system firmware. And like a reboot 1996 you can start any kernel with it, not just Linux. 1997 1998 The name comes from the similarity to the exec system call. 1999 2000 It is an ongoing process to be certain the hardware in a machine 2001 is properly shutdown, so do not be surprised if this code does not 2002 initially work for you. As of this writing the exact hardware 2003 interface is strongly in flux, so no good recommendation can be 2004 made. 2005 2006config KEXEC_FILE 2007 bool "kexec file based system call" 2008 select KEXEC_CORE 2009 select BUILD_BIN2C 2010 depends on X86_64 2011 depends on CRYPTO=y 2012 depends on CRYPTO_SHA256=y 2013 help 2014 This is new version of kexec system call. This system call is 2015 file based and takes file descriptors as system call argument 2016 for kernel and initramfs as opposed to list of segments as 2017 accepted by previous system call. 2018 2019config ARCH_HAS_KEXEC_PURGATORY 2020 def_bool KEXEC_FILE 2021 2022config KEXEC_SIG 2023 bool "Verify kernel signature during kexec_file_load() syscall" 2024 depends on KEXEC_FILE 2025 help 2026 2027 This option makes the kexec_file_load() syscall check for a valid 2028 signature of the kernel image. The image can still be loaded without 2029 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2030 there's a signature that we can check, then it must be valid. 2031 2032 In addition to this option, you need to enable signature 2033 verification for the corresponding kernel image type being 2034 loaded in order for this to work. 2035 2036config KEXEC_SIG_FORCE 2037 bool "Require a valid signature in kexec_file_load() syscall" 2038 depends on KEXEC_SIG 2039 help 2040 This option makes kernel signature verification mandatory for 2041 the kexec_file_load() syscall. 2042 2043config KEXEC_BZIMAGE_VERIFY_SIG 2044 bool "Enable bzImage signature verification support" 2045 depends on KEXEC_SIG 2046 depends on SIGNED_PE_FILE_VERIFICATION 2047 select SYSTEM_TRUSTED_KEYRING 2048 help 2049 Enable bzImage signature verification support. 2050 2051config CRASH_DUMP 2052 bool "kernel crash dumps" 2053 depends on X86_64 || (X86_32 && HIGHMEM) 2054 help 2055 Generate crash dump after being started by kexec. 2056 This should be normally only set in special crash dump kernels 2057 which are loaded in the main kernel with kexec-tools into 2058 a specially reserved region and then later executed after 2059 a crash by kdump/kexec. The crash dump kernel must be compiled 2060 to a memory address not used by the main kernel or BIOS using 2061 PHYSICAL_START, or it must be built as a relocatable image 2062 (CONFIG_RELOCATABLE=y). 2063 For more details see Documentation/admin-guide/kdump/kdump.rst 2064 2065config KEXEC_JUMP 2066 bool "kexec jump" 2067 depends on KEXEC && HIBERNATION 2068 help 2069 Jump between original kernel and kexeced kernel and invoke 2070 code in physical address mode via KEXEC 2071 2072config PHYSICAL_START 2073 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2074 default "0x1000000" 2075 help 2076 This gives the physical address where the kernel is loaded. 2077 2078 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2079 bzImage will decompress itself to above physical address and 2080 run from there. Otherwise, bzImage will run from the address where 2081 it has been loaded by the boot loader and will ignore above physical 2082 address. 2083 2084 In normal kdump cases one does not have to set/change this option 2085 as now bzImage can be compiled as a completely relocatable image 2086 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2087 address. This option is mainly useful for the folks who don't want 2088 to use a bzImage for capturing the crash dump and want to use a 2089 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2090 to be specifically compiled to run from a specific memory area 2091 (normally a reserved region) and this option comes handy. 2092 2093 So if you are using bzImage for capturing the crash dump, 2094 leave the value here unchanged to 0x1000000 and set 2095 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2096 for capturing the crash dump change this value to start of 2097 the reserved region. In other words, it can be set based on 2098 the "X" value as specified in the "crashkernel=YM@XM" 2099 command line boot parameter passed to the panic-ed 2100 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2101 for more details about crash dumps. 2102 2103 Usage of bzImage for capturing the crash dump is recommended as 2104 one does not have to build two kernels. Same kernel can be used 2105 as production kernel and capture kernel. Above option should have 2106 gone away after relocatable bzImage support is introduced. But it 2107 is present because there are users out there who continue to use 2108 vmlinux for dump capture. This option should go away down the 2109 line. 2110 2111 Don't change this unless you know what you are doing. 2112 2113config RELOCATABLE 2114 bool "Build a relocatable kernel" 2115 default y 2116 help 2117 This builds a kernel image that retains relocation information 2118 so it can be loaded someplace besides the default 1MB. 2119 The relocations tend to make the kernel binary about 10% larger, 2120 but are discarded at runtime. 2121 2122 One use is for the kexec on panic case where the recovery kernel 2123 must live at a different physical address than the primary 2124 kernel. 2125 2126 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2127 it has been loaded at and the compile time physical address 2128 (CONFIG_PHYSICAL_START) is used as the minimum location. 2129 2130config RANDOMIZE_BASE 2131 bool "Randomize the address of the kernel image (KASLR)" 2132 depends on RELOCATABLE 2133 default y 2134 help 2135 In support of Kernel Address Space Layout Randomization (KASLR), 2136 this randomizes the physical address at which the kernel image 2137 is decompressed and the virtual address where the kernel 2138 image is mapped, as a security feature that deters exploit 2139 attempts relying on knowledge of the location of kernel 2140 code internals. 2141 2142 On 64-bit, the kernel physical and virtual addresses are 2143 randomized separately. The physical address will be anywhere 2144 between 16MB and the top of physical memory (up to 64TB). The 2145 virtual address will be randomized from 16MB up to 1GB (9 bits 2146 of entropy). Note that this also reduces the memory space 2147 available to kernel modules from 1.5GB to 1GB. 2148 2149 On 32-bit, the kernel physical and virtual addresses are 2150 randomized together. They will be randomized from 16MB up to 2151 512MB (8 bits of entropy). 2152 2153 Entropy is generated using the RDRAND instruction if it is 2154 supported. If RDTSC is supported, its value is mixed into 2155 the entropy pool as well. If neither RDRAND nor RDTSC are 2156 supported, then entropy is read from the i8254 timer. The 2157 usable entropy is limited by the kernel being built using 2158 2GB addressing, and that PHYSICAL_ALIGN must be at a 2159 minimum of 2MB. As a result, only 10 bits of entropy are 2160 theoretically possible, but the implementations are further 2161 limited due to memory layouts. 2162 2163 If unsure, say Y. 2164 2165# Relocation on x86 needs some additional build support 2166config X86_NEED_RELOCS 2167 def_bool y 2168 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2169 2170config PHYSICAL_ALIGN 2171 hex "Alignment value to which kernel should be aligned" 2172 default "0x200000" 2173 range 0x2000 0x1000000 if X86_32 2174 range 0x200000 0x1000000 if X86_64 2175 help 2176 This value puts the alignment restrictions on physical address 2177 where kernel is loaded and run from. Kernel is compiled for an 2178 address which meets above alignment restriction. 2179 2180 If bootloader loads the kernel at a non-aligned address and 2181 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2182 address aligned to above value and run from there. 2183 2184 If bootloader loads the kernel at a non-aligned address and 2185 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2186 load address and decompress itself to the address it has been 2187 compiled for and run from there. The address for which kernel is 2188 compiled already meets above alignment restrictions. Hence the 2189 end result is that kernel runs from a physical address meeting 2190 above alignment restrictions. 2191 2192 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2193 this value must be a multiple of 0x200000. 2194 2195 Don't change this unless you know what you are doing. 2196 2197config DYNAMIC_MEMORY_LAYOUT 2198 bool 2199 help 2200 This option makes base addresses of vmalloc and vmemmap as well as 2201 __PAGE_OFFSET movable during boot. 2202 2203config RANDOMIZE_MEMORY 2204 bool "Randomize the kernel memory sections" 2205 depends on X86_64 2206 depends on RANDOMIZE_BASE 2207 select DYNAMIC_MEMORY_LAYOUT 2208 default RANDOMIZE_BASE 2209 help 2210 Randomizes the base virtual address of kernel memory sections 2211 (physical memory mapping, vmalloc & vmemmap). This security feature 2212 makes exploits relying on predictable memory locations less reliable. 2213 2214 The order of allocations remains unchanged. Entropy is generated in 2215 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2216 configuration have in average 30,000 different possible virtual 2217 addresses for each memory section. 2218 2219 If unsure, say Y. 2220 2221config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2222 hex "Physical memory mapping padding" if EXPERT 2223 depends on RANDOMIZE_MEMORY 2224 default "0xa" if MEMORY_HOTPLUG 2225 default "0x0" 2226 range 0x1 0x40 if MEMORY_HOTPLUG 2227 range 0x0 0x40 2228 help 2229 Define the padding in terabytes added to the existing physical 2230 memory size during kernel memory randomization. It is useful 2231 for memory hotplug support but reduces the entropy available for 2232 address randomization. 2233 2234 If unsure, leave at the default value. 2235 2236config HOTPLUG_CPU 2237 def_bool y 2238 depends on SMP 2239 2240config BOOTPARAM_HOTPLUG_CPU0 2241 bool "Set default setting of cpu0_hotpluggable" 2242 depends on HOTPLUG_CPU 2243 help 2244 Set whether default state of cpu0_hotpluggable is on or off. 2245 2246 Say Y here to enable CPU0 hotplug by default. If this switch 2247 is turned on, there is no need to give cpu0_hotplug kernel 2248 parameter and the CPU0 hotplug feature is enabled by default. 2249 2250 Please note: there are two known CPU0 dependencies if you want 2251 to enable the CPU0 hotplug feature either by this switch or by 2252 cpu0_hotplug kernel parameter. 2253 2254 First, resume from hibernate or suspend always starts from CPU0. 2255 So hibernate and suspend are prevented if CPU0 is offline. 2256 2257 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2258 offline if any interrupt can not migrate out of CPU0. There may 2259 be other CPU0 dependencies. 2260 2261 Please make sure the dependencies are under your control before 2262 you enable this feature. 2263 2264 Say N if you don't want to enable CPU0 hotplug feature by default. 2265 You still can enable the CPU0 hotplug feature at boot by kernel 2266 parameter cpu0_hotplug. 2267 2268config DEBUG_HOTPLUG_CPU0 2269 def_bool n 2270 prompt "Debug CPU0 hotplug" 2271 depends on HOTPLUG_CPU 2272 help 2273 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2274 soon as possible and boots up userspace with CPU0 offlined. User 2275 can online CPU0 back after boot time. 2276 2277 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2278 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2279 compilation or giving cpu0_hotplug kernel parameter at boot. 2280 2281 If unsure, say N. 2282 2283config COMPAT_VDSO 2284 def_bool n 2285 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2286 depends on COMPAT_32 2287 help 2288 Certain buggy versions of glibc will crash if they are 2289 presented with a 32-bit vDSO that is not mapped at the address 2290 indicated in its segment table. 2291 2292 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2293 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2294 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2295 the only released version with the bug, but OpenSUSE 9 2296 contains a buggy "glibc 2.3.2". 2297 2298 The symptom of the bug is that everything crashes on startup, saying: 2299 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2300 2301 Saying Y here changes the default value of the vdso32 boot 2302 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2303 This works around the glibc bug but hurts performance. 2304 2305 If unsure, say N: if you are compiling your own kernel, you 2306 are unlikely to be using a buggy version of glibc. 2307 2308choice 2309 prompt "vsyscall table for legacy applications" 2310 depends on X86_64 2311 default LEGACY_VSYSCALL_XONLY 2312 help 2313 Legacy user code that does not know how to find the vDSO expects 2314 to be able to issue three syscalls by calling fixed addresses in 2315 kernel space. Since this location is not randomized with ASLR, 2316 it can be used to assist security vulnerability exploitation. 2317 2318 This setting can be changed at boot time via the kernel command 2319 line parameter vsyscall=[emulate|xonly|none]. 2320 2321 On a system with recent enough glibc (2.14 or newer) and no 2322 static binaries, you can say None without a performance penalty 2323 to improve security. 2324 2325 If unsure, select "Emulate execution only". 2326 2327 config LEGACY_VSYSCALL_EMULATE 2328 bool "Full emulation" 2329 help 2330 The kernel traps and emulates calls into the fixed vsyscall 2331 address mapping. This makes the mapping non-executable, but 2332 it still contains readable known contents, which could be 2333 used in certain rare security vulnerability exploits. This 2334 configuration is recommended when using legacy userspace 2335 that still uses vsyscalls along with legacy binary 2336 instrumentation tools that require code to be readable. 2337 2338 An example of this type of legacy userspace is running 2339 Pin on an old binary that still uses vsyscalls. 2340 2341 config LEGACY_VSYSCALL_XONLY 2342 bool "Emulate execution only" 2343 help 2344 The kernel traps and emulates calls into the fixed vsyscall 2345 address mapping and does not allow reads. This 2346 configuration is recommended when userspace might use the 2347 legacy vsyscall area but support for legacy binary 2348 instrumentation of legacy code is not needed. It mitigates 2349 certain uses of the vsyscall area as an ASLR-bypassing 2350 buffer. 2351 2352 config LEGACY_VSYSCALL_NONE 2353 bool "None" 2354 help 2355 There will be no vsyscall mapping at all. This will 2356 eliminate any risk of ASLR bypass due to the vsyscall 2357 fixed address mapping. Attempts to use the vsyscalls 2358 will be reported to dmesg, so that either old or 2359 malicious userspace programs can be identified. 2360 2361endchoice 2362 2363config CMDLINE_BOOL 2364 bool "Built-in kernel command line" 2365 help 2366 Allow for specifying boot arguments to the kernel at 2367 build time. On some systems (e.g. embedded ones), it is 2368 necessary or convenient to provide some or all of the 2369 kernel boot arguments with the kernel itself (that is, 2370 to not rely on the boot loader to provide them.) 2371 2372 To compile command line arguments into the kernel, 2373 set this option to 'Y', then fill in the 2374 boot arguments in CONFIG_CMDLINE. 2375 2376 Systems with fully functional boot loaders (i.e. non-embedded) 2377 should leave this option set to 'N'. 2378 2379config CMDLINE 2380 string "Built-in kernel command string" 2381 depends on CMDLINE_BOOL 2382 default "" 2383 help 2384 Enter arguments here that should be compiled into the kernel 2385 image and used at boot time. If the boot loader provides a 2386 command line at boot time, it is appended to this string to 2387 form the full kernel command line, when the system boots. 2388 2389 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2390 change this behavior. 2391 2392 In most cases, the command line (whether built-in or provided 2393 by the boot loader) should specify the device for the root 2394 file system. 2395 2396config CMDLINE_OVERRIDE 2397 bool "Built-in command line overrides boot loader arguments" 2398 depends on CMDLINE_BOOL && CMDLINE != "" 2399 help 2400 Set this option to 'Y' to have the kernel ignore the boot loader 2401 command line, and use ONLY the built-in command line. 2402 2403 This is used to work around broken boot loaders. This should 2404 be set to 'N' under normal conditions. 2405 2406config MODIFY_LDT_SYSCALL 2407 bool "Enable the LDT (local descriptor table)" if EXPERT 2408 default y 2409 help 2410 Linux can allow user programs to install a per-process x86 2411 Local Descriptor Table (LDT) using the modify_ldt(2) system 2412 call. This is required to run 16-bit or segmented code such as 2413 DOSEMU or some Wine programs. It is also used by some very old 2414 threading libraries. 2415 2416 Enabling this feature adds a small amount of overhead to 2417 context switches and increases the low-level kernel attack 2418 surface. Disabling it removes the modify_ldt(2) system call. 2419 2420 Saying 'N' here may make sense for embedded or server kernels. 2421 2422source "kernel/livepatch/Kconfig" 2423 2424endmenu 2425 2426config ARCH_HAS_ADD_PAGES 2427 def_bool y 2428 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2429 2430config ARCH_ENABLE_MEMORY_HOTPLUG 2431 def_bool y 2432 depends on X86_64 || (X86_32 && HIGHMEM) 2433 2434config ARCH_ENABLE_MEMORY_HOTREMOVE 2435 def_bool y 2436 depends on MEMORY_HOTPLUG 2437 2438config USE_PERCPU_NUMA_NODE_ID 2439 def_bool y 2440 depends on NUMA 2441 2442config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2443 def_bool y 2444 depends on X86_64 || X86_PAE 2445 2446config ARCH_ENABLE_HUGEPAGE_MIGRATION 2447 def_bool y 2448 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2449 2450config ARCH_ENABLE_THP_MIGRATION 2451 def_bool y 2452 depends on X86_64 && TRANSPARENT_HUGEPAGE 2453 2454menu "Power management and ACPI options" 2455 2456config ARCH_HIBERNATION_HEADER 2457 def_bool y 2458 depends on HIBERNATION 2459 2460source "kernel/power/Kconfig" 2461 2462source "drivers/acpi/Kconfig" 2463 2464config X86_APM_BOOT 2465 def_bool y 2466 depends on APM 2467 2468menuconfig APM 2469 tristate "APM (Advanced Power Management) BIOS support" 2470 depends on X86_32 && PM_SLEEP 2471 help 2472 APM is a BIOS specification for saving power using several different 2473 techniques. This is mostly useful for battery powered laptops with 2474 APM compliant BIOSes. If you say Y here, the system time will be 2475 reset after a RESUME operation, the /proc/apm device will provide 2476 battery status information, and user-space programs will receive 2477 notification of APM "events" (e.g. battery status change). 2478 2479 If you select "Y" here, you can disable actual use of the APM 2480 BIOS by passing the "apm=off" option to the kernel at boot time. 2481 2482 Note that the APM support is almost completely disabled for 2483 machines with more than one CPU. 2484 2485 In order to use APM, you will need supporting software. For location 2486 and more information, read <file:Documentation/power/apm-acpi.rst> 2487 and the Battery Powered Linux mini-HOWTO, available from 2488 <http://www.tldp.org/docs.html#howto>. 2489 2490 This driver does not spin down disk drives (see the hdparm(8) 2491 manpage ("man 8 hdparm") for that), and it doesn't turn off 2492 VESA-compliant "green" monitors. 2493 2494 This driver does not support the TI 4000M TravelMate and the ACER 2495 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2496 desktop machines also don't have compliant BIOSes, and this driver 2497 may cause those machines to panic during the boot phase. 2498 2499 Generally, if you don't have a battery in your machine, there isn't 2500 much point in using this driver and you should say N. If you get 2501 random kernel OOPSes or reboots that don't seem to be related to 2502 anything, try disabling/enabling this option (or disabling/enabling 2503 APM in your BIOS). 2504 2505 Some other things you should try when experiencing seemingly random, 2506 "weird" problems: 2507 2508 1) make sure that you have enough swap space and that it is 2509 enabled. 2510 2) pass the "no-hlt" option to the kernel 2511 3) switch on floating point emulation in the kernel and pass 2512 the "no387" option to the kernel 2513 4) pass the "floppy=nodma" option to the kernel 2514 5) pass the "mem=4M" option to the kernel (thereby disabling 2515 all but the first 4 MB of RAM) 2516 6) make sure that the CPU is not over clocked. 2517 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2518 8) disable the cache from your BIOS settings 2519 9) install a fan for the video card or exchange video RAM 2520 10) install a better fan for the CPU 2521 11) exchange RAM chips 2522 12) exchange the motherboard. 2523 2524 To compile this driver as a module, choose M here: the 2525 module will be called apm. 2526 2527if APM 2528 2529config APM_IGNORE_USER_SUSPEND 2530 bool "Ignore USER SUSPEND" 2531 help 2532 This option will ignore USER SUSPEND requests. On machines with a 2533 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2534 series notebooks, it is necessary to say Y because of a BIOS bug. 2535 2536config APM_DO_ENABLE 2537 bool "Enable PM at boot time" 2538 help 2539 Enable APM features at boot time. From page 36 of the APM BIOS 2540 specification: "When disabled, the APM BIOS does not automatically 2541 power manage devices, enter the Standby State, enter the Suspend 2542 State, or take power saving steps in response to CPU Idle calls." 2543 This driver will make CPU Idle calls when Linux is idle (unless this 2544 feature is turned off -- see "Do CPU IDLE calls", below). This 2545 should always save battery power, but more complicated APM features 2546 will be dependent on your BIOS implementation. You may need to turn 2547 this option off if your computer hangs at boot time when using APM 2548 support, or if it beeps continuously instead of suspending. Turn 2549 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2550 T400CDT. This is off by default since most machines do fine without 2551 this feature. 2552 2553config APM_CPU_IDLE 2554 depends on CPU_IDLE 2555 bool "Make CPU Idle calls when idle" 2556 help 2557 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2558 On some machines, this can activate improved power savings, such as 2559 a slowed CPU clock rate, when the machine is idle. These idle calls 2560 are made after the idle loop has run for some length of time (e.g., 2561 333 mS). On some machines, this will cause a hang at boot time or 2562 whenever the CPU becomes idle. (On machines with more than one CPU, 2563 this option does nothing.) 2564 2565config APM_DISPLAY_BLANK 2566 bool "Enable console blanking using APM" 2567 help 2568 Enable console blanking using the APM. Some laptops can use this to 2569 turn off the LCD backlight when the screen blanker of the Linux 2570 virtual console blanks the screen. Note that this is only used by 2571 the virtual console screen blanker, and won't turn off the backlight 2572 when using the X Window system. This also doesn't have anything to 2573 do with your VESA-compliant power-saving monitor. Further, this 2574 option doesn't work for all laptops -- it might not turn off your 2575 backlight at all, or it might print a lot of errors to the console, 2576 especially if you are using gpm. 2577 2578config APM_ALLOW_INTS 2579 bool "Allow interrupts during APM BIOS calls" 2580 help 2581 Normally we disable external interrupts while we are making calls to 2582 the APM BIOS as a measure to lessen the effects of a badly behaving 2583 BIOS implementation. The BIOS should reenable interrupts if it 2584 needs to. Unfortunately, some BIOSes do not -- especially those in 2585 many of the newer IBM Thinkpads. If you experience hangs when you 2586 suspend, try setting this to Y. Otherwise, say N. 2587 2588endif # APM 2589 2590source "drivers/cpufreq/Kconfig" 2591 2592source "drivers/cpuidle/Kconfig" 2593 2594source "drivers/idle/Kconfig" 2595 2596endmenu 2597 2598 2599menu "Bus options (PCI etc.)" 2600 2601choice 2602 prompt "PCI access mode" 2603 depends on X86_32 && PCI 2604 default PCI_GOANY 2605 help 2606 On PCI systems, the BIOS can be used to detect the PCI devices and 2607 determine their configuration. However, some old PCI motherboards 2608 have BIOS bugs and may crash if this is done. Also, some embedded 2609 PCI-based systems don't have any BIOS at all. Linux can also try to 2610 detect the PCI hardware directly without using the BIOS. 2611 2612 With this option, you can specify how Linux should detect the 2613 PCI devices. If you choose "BIOS", the BIOS will be used, 2614 if you choose "Direct", the BIOS won't be used, and if you 2615 choose "MMConfig", then PCI Express MMCONFIG will be used. 2616 If you choose "Any", the kernel will try MMCONFIG, then the 2617 direct access method and falls back to the BIOS if that doesn't 2618 work. If unsure, go with the default, which is "Any". 2619 2620config PCI_GOBIOS 2621 bool "BIOS" 2622 2623config PCI_GOMMCONFIG 2624 bool "MMConfig" 2625 2626config PCI_GODIRECT 2627 bool "Direct" 2628 2629config PCI_GOOLPC 2630 bool "OLPC XO-1" 2631 depends on OLPC 2632 2633config PCI_GOANY 2634 bool "Any" 2635 2636endchoice 2637 2638config PCI_BIOS 2639 def_bool y 2640 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2641 2642# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2643config PCI_DIRECT 2644 def_bool y 2645 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2646 2647config PCI_MMCONFIG 2648 bool "Support mmconfig PCI config space access" if X86_64 2649 default y 2650 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2651 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2652 2653config PCI_OLPC 2654 def_bool y 2655 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2656 2657config PCI_XEN 2658 def_bool y 2659 depends on PCI && XEN 2660 select SWIOTLB_XEN 2661 2662config MMCONF_FAM10H 2663 def_bool y 2664 depends on X86_64 && PCI_MMCONFIG && ACPI 2665 2666config PCI_CNB20LE_QUIRK 2667 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2668 depends on PCI 2669 help 2670 Read the PCI windows out of the CNB20LE host bridge. This allows 2671 PCI hotplug to work on systems with the CNB20LE chipset which do 2672 not have ACPI. 2673 2674 There's no public spec for this chipset, and this functionality 2675 is known to be incomplete. 2676 2677 You should say N unless you know you need this. 2678 2679config ISA_BUS 2680 bool "ISA bus support on modern systems" if EXPERT 2681 help 2682 Expose ISA bus device drivers and options available for selection and 2683 configuration. Enable this option if your target machine has an ISA 2684 bus. ISA is an older system, displaced by PCI and newer bus 2685 architectures -- if your target machine is modern, it probably does 2686 not have an ISA bus. 2687 2688 If unsure, say N. 2689 2690# x86_64 have no ISA slots, but can have ISA-style DMA. 2691config ISA_DMA_API 2692 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2693 default y 2694 help 2695 Enables ISA-style DMA support for devices requiring such controllers. 2696 If unsure, say Y. 2697 2698if X86_32 2699 2700config ISA 2701 bool "ISA support" 2702 help 2703 Find out whether you have ISA slots on your motherboard. ISA is the 2704 name of a bus system, i.e. the way the CPU talks to the other stuff 2705 inside your box. Other bus systems are PCI, EISA, MicroChannel 2706 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2707 newer boards don't support it. If you have ISA, say Y, otherwise N. 2708 2709config SCx200 2710 tristate "NatSemi SCx200 support" 2711 help 2712 This provides basic support for National Semiconductor's 2713 (now AMD's) Geode processors. The driver probes for the 2714 PCI-IDs of several on-chip devices, so its a good dependency 2715 for other scx200_* drivers. 2716 2717 If compiled as a module, the driver is named scx200. 2718 2719config SCx200HR_TIMER 2720 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2721 depends on SCx200 2722 default y 2723 help 2724 This driver provides a clocksource built upon the on-chip 2725 27MHz high-resolution timer. Its also a workaround for 2726 NSC Geode SC-1100's buggy TSC, which loses time when the 2727 processor goes idle (as is done by the scheduler). The 2728 other workaround is idle=poll boot option. 2729 2730config OLPC 2731 bool "One Laptop Per Child support" 2732 depends on !X86_PAE 2733 select GPIOLIB 2734 select OF 2735 select OF_PROMTREE 2736 select IRQ_DOMAIN 2737 select OLPC_EC 2738 help 2739 Add support for detecting the unique features of the OLPC 2740 XO hardware. 2741 2742config OLPC_XO1_PM 2743 bool "OLPC XO-1 Power Management" 2744 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2745 help 2746 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2747 2748config OLPC_XO1_RTC 2749 bool "OLPC XO-1 Real Time Clock" 2750 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2751 help 2752 Add support for the XO-1 real time clock, which can be used as a 2753 programmable wakeup source. 2754 2755config OLPC_XO1_SCI 2756 bool "OLPC XO-1 SCI extras" 2757 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2758 depends on INPUT=y 2759 select POWER_SUPPLY 2760 help 2761 Add support for SCI-based features of the OLPC XO-1 laptop: 2762 - EC-driven system wakeups 2763 - Power button 2764 - Ebook switch 2765 - Lid switch 2766 - AC adapter status updates 2767 - Battery status updates 2768 2769config OLPC_XO15_SCI 2770 bool "OLPC XO-1.5 SCI extras" 2771 depends on OLPC && ACPI 2772 select POWER_SUPPLY 2773 help 2774 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2775 - EC-driven system wakeups 2776 - AC adapter status updates 2777 - Battery status updates 2778 2779config ALIX 2780 bool "PCEngines ALIX System Support (LED setup)" 2781 select GPIOLIB 2782 help 2783 This option enables system support for the PCEngines ALIX. 2784 At present this just sets up LEDs for GPIO control on 2785 ALIX2/3/6 boards. However, other system specific setup should 2786 get added here. 2787 2788 Note: You must still enable the drivers for GPIO and LED support 2789 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2790 2791 Note: You have to set alix.force=1 for boards with Award BIOS. 2792 2793config NET5501 2794 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2795 select GPIOLIB 2796 help 2797 This option enables system support for the Soekris Engineering net5501. 2798 2799config GEOS 2800 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2801 select GPIOLIB 2802 depends on DMI 2803 help 2804 This option enables system support for the Traverse Technologies GEOS. 2805 2806config TS5500 2807 bool "Technologic Systems TS-5500 platform support" 2808 depends on MELAN 2809 select CHECK_SIGNATURE 2810 select NEW_LEDS 2811 select LEDS_CLASS 2812 help 2813 This option enables system support for the Technologic Systems TS-5500. 2814 2815endif # X86_32 2816 2817config AMD_NB 2818 def_bool y 2819 depends on CPU_SUP_AMD && PCI 2820 2821config X86_SYSFB 2822 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2823 help 2824 Firmwares often provide initial graphics framebuffers so the BIOS, 2825 bootloader or kernel can show basic video-output during boot for 2826 user-guidance and debugging. Historically, x86 used the VESA BIOS 2827 Extensions and EFI-framebuffers for this, which are mostly limited 2828 to x86. 2829 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2830 framebuffers so the new generic system-framebuffer drivers can be 2831 used on x86. If the framebuffer is not compatible with the generic 2832 modes, it is advertised as fallback platform framebuffer so legacy 2833 drivers like efifb, vesafb and uvesafb can pick it up. 2834 If this option is not selected, all system framebuffers are always 2835 marked as fallback platform framebuffers as usual. 2836 2837 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2838 not be able to pick up generic system framebuffers if this option 2839 is selected. You are highly encouraged to enable simplefb as 2840 replacement if you select this option. simplefb can correctly deal 2841 with generic system framebuffers. But you should still keep vesafb 2842 and others enabled as fallback if a system framebuffer is 2843 incompatible with simplefb. 2844 2845 If unsure, say Y. 2846 2847endmenu 2848 2849 2850menu "Binary Emulations" 2851 2852config IA32_EMULATION 2853 bool "IA32 Emulation" 2854 depends on X86_64 2855 select ARCH_WANT_OLD_COMPAT_IPC 2856 select BINFMT_ELF 2857 select COMPAT_OLD_SIGACTION 2858 help 2859 Include code to run legacy 32-bit programs under a 2860 64-bit kernel. You should likely turn this on, unless you're 2861 100% sure that you don't have any 32-bit programs left. 2862 2863config IA32_AOUT 2864 tristate "IA32 a.out support" 2865 depends on IA32_EMULATION 2866 depends on BROKEN 2867 help 2868 Support old a.out binaries in the 32bit emulation. 2869 2870config X86_X32 2871 bool "x32 ABI for 64-bit mode" 2872 depends on X86_64 2873 help 2874 Include code to run binaries for the x32 native 32-bit ABI 2875 for 64-bit processors. An x32 process gets access to the 2876 full 64-bit register file and wide data path while leaving 2877 pointers at 32 bits for smaller memory footprint. 2878 2879 You will need a recent binutils (2.22 or later) with 2880 elf32_x86_64 support enabled to compile a kernel with this 2881 option set. 2882 2883config COMPAT_32 2884 def_bool y 2885 depends on IA32_EMULATION || X86_32 2886 select HAVE_UID16 2887 select OLD_SIGSUSPEND3 2888 2889config COMPAT 2890 def_bool y 2891 depends on IA32_EMULATION || X86_X32 2892 2893if COMPAT 2894config COMPAT_FOR_U64_ALIGNMENT 2895 def_bool y 2896 2897config SYSVIPC_COMPAT 2898 def_bool y 2899 depends on SYSVIPC 2900endif 2901 2902endmenu 2903 2904 2905config HAVE_ATOMIC_IOMAP 2906 def_bool y 2907 depends on X86_32 2908 2909source "drivers/firmware/Kconfig" 2910 2911source "arch/x86/kvm/Kconfig" 2912 2913source "arch/x86/Kconfig.assembler" 2914