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_SUPPORTS_PER_VMA_LOCK 31 select HAVE_ARCH_SOFT_DIRTY 32 select MODULES_USE_ELF_RELA 33 select NEED_DMA_MAP_STATE 34 select SWIOTLB 35 select ARCH_HAS_ELFCORE_COMPAT 36 select ZONE_DMA32 37 select EXECMEM if DYNAMIC_FTRACE 38 39config FORCE_DYNAMIC_FTRACE 40 def_bool y 41 depends on X86_32 42 depends on FUNCTION_TRACER 43 select DYNAMIC_FTRACE 44 help 45 We keep the static function tracing (!DYNAMIC_FTRACE) around 46 in order to test the non static function tracing in the 47 generic code, as other architectures still use it. But we 48 only need to keep it around for x86_64. No need to keep it 49 for x86_32. For x86_32, force DYNAMIC_FTRACE. 50# 51# Arch settings 52# 53# ( Note that options that are marked 'if X86_64' could in principle be 54# ported to 32-bit as well. ) 55# 56config X86 57 def_bool y 58 # 59 # Note: keep this list sorted alphabetically 60 # 61 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 62 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 63 select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU 64 select ARCH_32BIT_OFF_T if X86_32 65 select ARCH_CLOCKSOURCE_INIT 66 select ARCH_CONFIGURES_CPU_MITIGATIONS 67 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 68 select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION 69 select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 70 select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG 71 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 72 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 73 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 74 select ARCH_HAS_CACHE_LINE_SIZE 75 select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION 76 select ARCH_HAS_CPU_FINALIZE_INIT 77 select ARCH_HAS_CPU_PASID if IOMMU_SVA 78 select ARCH_HAS_CURRENT_STACK_POINTER 79 select ARCH_HAS_DEBUG_VIRTUAL 80 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 81 select ARCH_HAS_DEVMEM_IS_ALLOWED 82 select ARCH_HAS_DMA_OPS if GART_IOMMU || XEN 83 select ARCH_HAS_EARLY_DEBUG if KGDB 84 select ARCH_HAS_ELF_RANDOMIZE 85 select ARCH_HAS_FAST_MULTIPLIER 86 select ARCH_HAS_FORTIFY_SOURCE 87 select ARCH_HAS_GCOV_PROFILE_ALL 88 select ARCH_HAS_KCOV if X86_64 89 select ARCH_HAS_KERNEL_FPU_SUPPORT 90 select ARCH_HAS_MEM_ENCRYPT 91 select ARCH_HAS_MEMBARRIER_SYNC_CORE 92 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 93 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 94 select ARCH_HAS_PMEM_API if X86_64 95 select ARCH_HAS_PTE_DEVMAP if X86_64 96 select ARCH_HAS_PTE_SPECIAL 97 select ARCH_HAS_HW_PTE_YOUNG 98 select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 99 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 100 select ARCH_HAS_COPY_MC if X86_64 101 select ARCH_HAS_SET_MEMORY 102 select ARCH_HAS_SET_DIRECT_MAP 103 select ARCH_HAS_STRICT_KERNEL_RWX 104 select ARCH_HAS_STRICT_MODULE_RWX 105 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 106 select ARCH_HAS_SYSCALL_WRAPPER 107 select ARCH_HAS_UBSAN 108 select ARCH_HAS_DEBUG_WX 109 select ARCH_HAS_ZONE_DMA_SET if EXPERT 110 select ARCH_HAVE_NMI_SAFE_CMPXCHG 111 select ARCH_HAVE_EXTRA_ELF_NOTES 112 select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 113 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 114 select ARCH_MIGHT_HAVE_PC_PARPORT 115 select ARCH_MIGHT_HAVE_PC_SERIO 116 select ARCH_STACKWALK 117 select ARCH_SUPPORTS_ACPI 118 select ARCH_SUPPORTS_ATOMIC_RMW 119 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 120 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 121 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 122 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 123 select ARCH_SUPPORTS_CFI_CLANG if X86_64 124 select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG 125 select ARCH_SUPPORTS_LTO_CLANG 126 select ARCH_SUPPORTS_LTO_CLANG_THIN 127 select ARCH_SUPPORTS_RT 128 select ARCH_USE_BUILTIN_BSWAP 129 select ARCH_USE_CMPXCHG_LOCKREF if X86_CMPXCHG64 130 select ARCH_USE_MEMTEST 131 select ARCH_USE_QUEUED_RWLOCKS 132 select ARCH_USE_QUEUED_SPINLOCKS 133 select ARCH_USE_SYM_ANNOTATIONS 134 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 135 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 136 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 137 select ARCH_WANTS_NO_INSTR 138 select ARCH_WANT_GENERAL_HUGETLB 139 select ARCH_WANT_HUGE_PMD_SHARE 140 select ARCH_WANT_LD_ORPHAN_WARN 141 select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP if X86_64 142 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP if X86_64 143 select ARCH_WANTS_THP_SWAP if X86_64 144 select ARCH_HAS_PARANOID_L1D_FLUSH 145 select BUILDTIME_TABLE_SORT 146 select CLKEVT_I8253 147 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 148 select CLOCKSOURCE_WATCHDOG 149 # Word-size accesses may read uninitialized data past the trailing \0 150 # in strings and cause false KMSAN reports. 151 select DCACHE_WORD_ACCESS if !KMSAN 152 select DYNAMIC_SIGFRAME 153 select EDAC_ATOMIC_SCRUB 154 select EDAC_SUPPORT 155 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 156 select GENERIC_CLOCKEVENTS_BROADCAST_IDLE if GENERIC_CLOCKEVENTS_BROADCAST 157 select GENERIC_CLOCKEVENTS_MIN_ADJUST 158 select GENERIC_CMOS_UPDATE 159 select GENERIC_CPU_AUTOPROBE 160 select GENERIC_CPU_DEVICES 161 select GENERIC_CPU_VULNERABILITIES 162 select GENERIC_EARLY_IOREMAP 163 select GENERIC_ENTRY 164 select GENERIC_IOMAP 165 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 166 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 167 select GENERIC_IRQ_MIGRATION if SMP 168 select GENERIC_IRQ_PROBE 169 select GENERIC_IRQ_RESERVATION_MODE 170 select GENERIC_IRQ_SHOW 171 select GENERIC_PENDING_IRQ if SMP 172 select GENERIC_PTDUMP 173 select GENERIC_SMP_IDLE_THREAD 174 select GENERIC_TIME_VSYSCALL 175 select GENERIC_GETTIMEOFDAY 176 select GENERIC_VDSO_TIME_NS 177 select GENERIC_VDSO_OVERFLOW_PROTECT 178 select GUP_GET_PXX_LOW_HIGH if X86_PAE 179 select HARDIRQS_SW_RESEND 180 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 181 select HAS_IOPORT 182 select HAVE_ACPI_APEI if ACPI 183 select HAVE_ACPI_APEI_NMI if ACPI 184 select HAVE_ALIGNED_STRUCT_PAGE 185 select HAVE_ARCH_AUDITSYSCALL 186 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 187 select HAVE_ARCH_HUGE_VMALLOC if X86_64 188 select HAVE_ARCH_JUMP_LABEL 189 select HAVE_ARCH_JUMP_LABEL_RELATIVE 190 select HAVE_ARCH_KASAN if X86_64 191 select HAVE_ARCH_KASAN_VMALLOC if X86_64 192 select HAVE_ARCH_KFENCE 193 select HAVE_ARCH_KMSAN if X86_64 194 select HAVE_ARCH_KGDB 195 select HAVE_ARCH_MMAP_RND_BITS if MMU 196 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 197 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 198 select HAVE_ARCH_PREL32_RELOCATIONS 199 select HAVE_ARCH_SECCOMP_FILTER 200 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 201 select HAVE_ARCH_STACKLEAK 202 select HAVE_ARCH_TRACEHOOK 203 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 204 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 205 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 206 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 207 select HAVE_ARCH_VMAP_STACK if X86_64 208 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 209 select HAVE_ARCH_WITHIN_STACK_FRAMES 210 select HAVE_ASM_MODVERSIONS 211 select HAVE_CMPXCHG_DOUBLE 212 select HAVE_CMPXCHG_LOCAL 213 select HAVE_CONTEXT_TRACKING_USER if X86_64 214 select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER 215 select HAVE_C_RECORDMCOUNT 216 select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 217 select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT 218 select HAVE_BUILDTIME_MCOUNT_SORT 219 select HAVE_DEBUG_KMEMLEAK 220 select HAVE_DMA_CONTIGUOUS 221 select HAVE_DYNAMIC_FTRACE 222 select HAVE_DYNAMIC_FTRACE_WITH_REGS 223 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 224 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 225 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 226 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 227 select HAVE_EBPF_JIT 228 select HAVE_EFFICIENT_UNALIGNED_ACCESS 229 select HAVE_EISA 230 select HAVE_EXIT_THREAD 231 select HAVE_GUP_FAST 232 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 233 select HAVE_FTRACE_MCOUNT_RECORD 234 select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER 235 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 236 select HAVE_FUNCTION_TRACER 237 select HAVE_GCC_PLUGINS 238 select HAVE_HW_BREAKPOINT 239 select HAVE_IOREMAP_PROT 240 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 241 select HAVE_IRQ_TIME_ACCOUNTING 242 select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 243 select HAVE_KERNEL_BZIP2 244 select HAVE_KERNEL_GZIP 245 select HAVE_KERNEL_LZ4 246 select HAVE_KERNEL_LZMA 247 select HAVE_KERNEL_LZO 248 select HAVE_KERNEL_XZ 249 select HAVE_KERNEL_ZSTD 250 select HAVE_KPROBES 251 select HAVE_KPROBES_ON_FTRACE 252 select HAVE_FUNCTION_ERROR_INJECTION 253 select HAVE_KRETPROBES 254 select HAVE_RETHOOK 255 select HAVE_LIVEPATCH if X86_64 256 select HAVE_MIXED_BREAKPOINTS_REGS 257 select HAVE_MOD_ARCH_SPECIFIC 258 select HAVE_MOVE_PMD 259 select HAVE_MOVE_PUD 260 select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 261 select HAVE_NMI 262 select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 263 select HAVE_OBJTOOL if X86_64 264 select HAVE_OPTPROBES 265 select HAVE_PAGE_SIZE_4KB 266 select HAVE_PCSPKR_PLATFORM 267 select HAVE_PERF_EVENTS 268 select HAVE_PERF_EVENTS_NMI 269 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 270 select HAVE_PCI 271 select HAVE_PERF_REGS 272 select HAVE_PERF_USER_STACK_DUMP 273 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 274 select MMU_GATHER_MERGE_VMAS 275 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 276 select HAVE_REGS_AND_STACK_ACCESS_API 277 select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 278 select HAVE_FUNCTION_ARG_ACCESS_API 279 select HAVE_SETUP_PER_CPU_AREA 280 select HAVE_SOFTIRQ_ON_OWN_STACK 281 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 282 select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 283 select HAVE_STATIC_CALL 284 select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 285 select HAVE_PREEMPT_DYNAMIC_CALL 286 select HAVE_RSEQ 287 select HAVE_RUST if X86_64 288 select HAVE_SYSCALL_TRACEPOINTS 289 select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 290 select HAVE_UNSTABLE_SCHED_CLOCK 291 select HAVE_USER_RETURN_NOTIFIER 292 select HAVE_GENERIC_VDSO 293 select VDSO_GETRANDOM if X86_64 294 select HOTPLUG_PARALLEL if SMP && X86_64 295 select HOTPLUG_SMT if SMP 296 select HOTPLUG_SPLIT_STARTUP if SMP && X86_32 297 select IRQ_FORCED_THREADING 298 select LOCK_MM_AND_FIND_VMA 299 select NEED_PER_CPU_EMBED_FIRST_CHUNK 300 select NEED_PER_CPU_PAGE_FIRST_CHUNK 301 select NEED_SG_DMA_LENGTH 302 select PCI_DOMAINS if PCI 303 select PCI_LOCKLESS_CONFIG if PCI 304 select PERF_EVENTS 305 select RTC_LIB 306 select RTC_MC146818_LIB 307 select SPARSE_IRQ 308 select SYSCTL_EXCEPTION_TRACE 309 select THREAD_INFO_IN_TASK 310 select TRACE_IRQFLAGS_SUPPORT 311 select TRACE_IRQFLAGS_NMI_SUPPORT 312 select USER_STACKTRACE_SUPPORT 313 select HAVE_ARCH_KCSAN if X86_64 314 select PROC_PID_ARCH_STATUS if PROC_FS 315 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 316 select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 317 select FUNCTION_ALIGNMENT_4B 318 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 319 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 320 321config INSTRUCTION_DECODER 322 def_bool y 323 depends on KPROBES || PERF_EVENTS || UPROBES 324 325config OUTPUT_FORMAT 326 string 327 default "elf32-i386" if X86_32 328 default "elf64-x86-64" if X86_64 329 330config LOCKDEP_SUPPORT 331 def_bool y 332 333config STACKTRACE_SUPPORT 334 def_bool y 335 336config MMU 337 def_bool y 338 339config ARCH_MMAP_RND_BITS_MIN 340 default 28 if 64BIT 341 default 8 342 343config ARCH_MMAP_RND_BITS_MAX 344 default 32 if 64BIT 345 default 16 346 347config ARCH_MMAP_RND_COMPAT_BITS_MIN 348 default 8 349 350config ARCH_MMAP_RND_COMPAT_BITS_MAX 351 default 16 352 353config SBUS 354 bool 355 356config GENERIC_ISA_DMA 357 def_bool y 358 depends on ISA_DMA_API 359 360config GENERIC_CSUM 361 bool 362 default y if KMSAN || KASAN 363 364config GENERIC_BUG 365 def_bool y 366 depends on BUG 367 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 368 369config GENERIC_BUG_RELATIVE_POINTERS 370 bool 371 372config ARCH_MAY_HAVE_PC_FDC 373 def_bool y 374 depends on ISA_DMA_API 375 376config GENERIC_CALIBRATE_DELAY 377 def_bool y 378 379config ARCH_HAS_CPU_RELAX 380 def_bool y 381 382config ARCH_HIBERNATION_POSSIBLE 383 def_bool y 384 385config ARCH_SUSPEND_POSSIBLE 386 def_bool y 387 388config AUDIT_ARCH 389 def_bool y if X86_64 390 391config KASAN_SHADOW_OFFSET 392 hex 393 depends on KASAN 394 default 0xdffffc0000000000 395 396config HAVE_INTEL_TXT 397 def_bool y 398 depends on INTEL_IOMMU && ACPI 399 400config X86_64_SMP 401 def_bool y 402 depends on X86_64 && SMP 403 404config ARCH_SUPPORTS_UPROBES 405 def_bool y 406 407config FIX_EARLYCON_MEM 408 def_bool y 409 410config DYNAMIC_PHYSICAL_MASK 411 bool 412 413config PGTABLE_LEVELS 414 int 415 default 5 if X86_5LEVEL 416 default 4 if X86_64 417 default 3 if X86_PAE 418 default 2 419 420config CC_HAS_SANE_STACKPROTECTOR 421 bool 422 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT 423 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) 424 help 425 We have to make sure stack protector is unconditionally disabled if 426 the compiler produces broken code or if it does not let us control 427 the segment on 32-bit kernels. 428 429menu "Processor type and features" 430 431config SMP 432 bool "Symmetric multi-processing support" 433 help 434 This enables support for systems with more than one CPU. If you have 435 a system with only one CPU, say N. If you have a system with more 436 than one CPU, say Y. 437 438 If you say N here, the kernel will run on uni- and multiprocessor 439 machines, but will use only one CPU of a multiprocessor machine. If 440 you say Y here, the kernel will run on many, but not all, 441 uniprocessor machines. On a uniprocessor machine, the kernel 442 will run faster if you say N here. 443 444 Note that if you say Y here and choose architecture "586" or 445 "Pentium" under "Processor family", the kernel will not work on 486 446 architectures. Similarly, multiprocessor kernels for the "PPro" 447 architecture may not work on all Pentium based boards. 448 449 People using multiprocessor machines who say Y here should also say 450 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 451 Management" code will be disabled if you say Y here. 452 453 See also <file:Documentation/arch/x86/i386/IO-APIC.rst>, 454 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 455 <http://www.tldp.org/docs.html#howto>. 456 457 If you don't know what to do here, say N. 458 459config X86_X2APIC 460 bool "Support x2apic" 461 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 462 help 463 This enables x2apic support on CPUs that have this feature. 464 465 This allows 32-bit apic IDs (so it can support very large systems), 466 and accesses the local apic via MSRs not via mmio. 467 468 Some Intel systems circa 2022 and later are locked into x2APIC mode 469 and can not fall back to the legacy APIC modes if SGX or TDX are 470 enabled in the BIOS. They will boot with very reduced functionality 471 without enabling this option. 472 473 If you don't know what to do here, say N. 474 475config X86_POSTED_MSI 476 bool "Enable MSI and MSI-x delivery by posted interrupts" 477 depends on X86_64 && IRQ_REMAP 478 help 479 This enables MSIs that are under interrupt remapping to be delivered as 480 posted interrupts to the host kernel. Interrupt throughput can 481 potentially be improved by coalescing CPU notifications during high 482 frequency bursts. 483 484 If you don't know what to do here, say N. 485 486config X86_MPPARSE 487 bool "Enable MPS table" if ACPI 488 default y 489 depends on X86_LOCAL_APIC 490 help 491 For old smp systems that do not have proper acpi support. Newer systems 492 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 493 494config X86_CPU_RESCTRL 495 bool "x86 CPU resource control support" 496 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 497 select KERNFS 498 select PROC_CPU_RESCTRL if PROC_FS 499 help 500 Enable x86 CPU resource control support. 501 502 Provide support for the allocation and monitoring of system resources 503 usage by the CPU. 504 505 Intel calls this Intel Resource Director Technology 506 (Intel(R) RDT). More information about RDT can be found in the 507 Intel x86 Architecture Software Developer Manual. 508 509 AMD calls this AMD Platform Quality of Service (AMD QoS). 510 More information about AMD QoS can be found in the AMD64 Technology 511 Platform Quality of Service Extensions manual. 512 513 Say N if unsure. 514 515config X86_FRED 516 bool "Flexible Return and Event Delivery" 517 depends on X86_64 518 help 519 When enabled, try to use Flexible Return and Event Delivery 520 instead of the legacy SYSCALL/SYSENTER/IDT architecture for 521 ring transitions and exception/interrupt handling if the 522 system supports it. 523 524config X86_BIGSMP 525 bool "Support for big SMP systems with more than 8 CPUs" 526 depends on SMP && X86_32 527 help 528 This option is needed for the systems that have more than 8 CPUs. 529 530config X86_EXTENDED_PLATFORM 531 bool "Support for extended (non-PC) x86 platforms" 532 default y 533 help 534 If you disable this option then the kernel will only support 535 standard PC platforms. (which covers the vast majority of 536 systems out there.) 537 538 If you enable this option then you'll be able to select support 539 for the following non-PC x86 platforms, depending on the value of 540 CONFIG_64BIT. 541 542 32-bit platforms (CONFIG_64BIT=n): 543 Goldfish (Android emulator) 544 AMD Elan 545 RDC R-321x SoC 546 SGI 320/540 (Visual Workstation) 547 STA2X11-based (e.g. Northville) 548 Moorestown MID devices 549 550 64-bit platforms (CONFIG_64BIT=y): 551 Numascale NumaChip 552 ScaleMP vSMP 553 SGI Ultraviolet 554 555 If you have one of these systems, or if you want to build a 556 generic distribution kernel, say Y here - otherwise say N. 557 558# This is an alphabetically sorted list of 64 bit extended platforms 559# Please maintain the alphabetic order if and when there are additions 560config X86_NUMACHIP 561 bool "Numascale NumaChip" 562 depends on X86_64 563 depends on X86_EXTENDED_PLATFORM 564 depends on NUMA 565 depends on SMP 566 depends on X86_X2APIC 567 depends on PCI_MMCONFIG 568 help 569 Adds support for Numascale NumaChip large-SMP systems. Needed to 570 enable more than ~168 cores. 571 If you don't have one of these, you should say N here. 572 573config X86_VSMP 574 bool "ScaleMP vSMP" 575 select HYPERVISOR_GUEST 576 select PARAVIRT 577 depends on X86_64 && PCI 578 depends on X86_EXTENDED_PLATFORM 579 depends on SMP 580 help 581 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 582 supposed to run on these EM64T-based machines. Only choose this option 583 if you have one of these machines. 584 585config X86_UV 586 bool "SGI Ultraviolet" 587 depends on X86_64 588 depends on X86_EXTENDED_PLATFORM 589 depends on NUMA 590 depends on EFI 591 depends on KEXEC_CORE 592 depends on X86_X2APIC 593 depends on PCI 594 help 595 This option is needed in order to support SGI Ultraviolet systems. 596 If you don't have one of these, you should say N here. 597 598# Following is an alphabetically sorted list of 32 bit extended platforms 599# Please maintain the alphabetic order if and when there are additions 600 601config X86_GOLDFISH 602 bool "Goldfish (Virtual Platform)" 603 depends on X86_EXTENDED_PLATFORM 604 help 605 Enable support for the Goldfish virtual platform used primarily 606 for Android development. Unless you are building for the Android 607 Goldfish emulator say N here. 608 609config X86_INTEL_CE 610 bool "CE4100 TV platform" 611 depends on PCI 612 depends on PCI_GODIRECT 613 depends on X86_IO_APIC 614 depends on X86_32 615 depends on X86_EXTENDED_PLATFORM 616 select X86_REBOOTFIXUPS 617 select OF 618 select OF_EARLY_FLATTREE 619 help 620 Select for the Intel CE media processor (CE4100) SOC. 621 This option compiles in support for the CE4100 SOC for settop 622 boxes and media devices. 623 624config X86_INTEL_MID 625 bool "Intel MID platform support" 626 depends on X86_EXTENDED_PLATFORM 627 depends on X86_PLATFORM_DEVICES 628 depends on PCI 629 depends on X86_64 || (PCI_GOANY && X86_32) 630 depends on X86_IO_APIC 631 select I2C 632 select DW_APB_TIMER 633 select INTEL_SCU_PCI 634 help 635 Select to build a kernel capable of supporting Intel MID (Mobile 636 Internet Device) platform systems which do not have the PCI legacy 637 interfaces. If you are building for a PC class system say N here. 638 639 Intel MID platforms are based on an Intel processor and chipset which 640 consume less power than most of the x86 derivatives. 641 642config X86_INTEL_QUARK 643 bool "Intel Quark platform support" 644 depends on X86_32 645 depends on X86_EXTENDED_PLATFORM 646 depends on X86_PLATFORM_DEVICES 647 depends on X86_TSC 648 depends on PCI 649 depends on PCI_GOANY 650 depends on X86_IO_APIC 651 select IOSF_MBI 652 select INTEL_IMR 653 select COMMON_CLK 654 help 655 Select to include support for Quark X1000 SoC. 656 Say Y here if you have a Quark based system such as the Arduino 657 compatible Intel Galileo. 658 659config X86_INTEL_LPSS 660 bool "Intel Low Power Subsystem Support" 661 depends on X86 && ACPI && PCI 662 select COMMON_CLK 663 select PINCTRL 664 select IOSF_MBI 665 help 666 Select to build support for Intel Low Power Subsystem such as 667 found on Intel Lynxpoint PCH. Selecting this option enables 668 things like clock tree (common clock framework) and pincontrol 669 which are needed by the LPSS peripheral drivers. 670 671config X86_AMD_PLATFORM_DEVICE 672 bool "AMD ACPI2Platform devices support" 673 depends on ACPI 674 select COMMON_CLK 675 select PINCTRL 676 help 677 Select to interpret AMD specific ACPI device to platform device 678 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 679 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 680 implemented under PINCTRL subsystem. 681 682config IOSF_MBI 683 tristate "Intel SoC IOSF Sideband support for SoC platforms" 684 depends on PCI 685 help 686 This option enables sideband register access support for Intel SoC 687 platforms. On these platforms the IOSF sideband is used in lieu of 688 MSR's for some register accesses, mostly but not limited to thermal 689 and power. Drivers may query the availability of this device to 690 determine if they need the sideband in order to work on these 691 platforms. The sideband is available on the following SoC products. 692 This list is not meant to be exclusive. 693 - BayTrail 694 - Braswell 695 - Quark 696 697 You should say Y if you are running a kernel on one of these SoC's. 698 699config IOSF_MBI_DEBUG 700 bool "Enable IOSF sideband access through debugfs" 701 depends on IOSF_MBI && DEBUG_FS 702 help 703 Select this option to expose the IOSF sideband access registers (MCR, 704 MDR, MCRX) through debugfs to write and read register information from 705 different units on the SoC. This is most useful for obtaining device 706 state information for debug and analysis. As this is a general access 707 mechanism, users of this option would have specific knowledge of the 708 device they want to access. 709 710 If you don't require the option or are in doubt, say N. 711 712config X86_RDC321X 713 bool "RDC R-321x SoC" 714 depends on X86_32 715 depends on X86_EXTENDED_PLATFORM 716 select M486 717 select X86_REBOOTFIXUPS 718 help 719 This option is needed for RDC R-321x system-on-chip, also known 720 as R-8610-(G). 721 If you don't have one of these chips, you should say N here. 722 723config X86_32_NON_STANDARD 724 bool "Support non-standard 32-bit SMP architectures" 725 depends on X86_32 && SMP 726 depends on X86_EXTENDED_PLATFORM 727 help 728 This option compiles in the bigsmp and STA2X11 default 729 subarchitectures. It is intended for a generic binary 730 kernel. If you select them all, kernel will probe it one by 731 one and will fallback to default. 732 733# Alphabetically sorted list of Non standard 32 bit platforms 734 735config X86_SUPPORTS_MEMORY_FAILURE 736 def_bool y 737 # MCE code calls memory_failure(): 738 depends on X86_MCE 739 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 740 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 741 depends on X86_64 || !SPARSEMEM 742 select ARCH_SUPPORTS_MEMORY_FAILURE 743 744config STA2X11 745 bool "STA2X11 Companion Chip Support" 746 depends on X86_32_NON_STANDARD && PCI 747 select SWIOTLB 748 select MFD_STA2X11 749 select GPIOLIB 750 help 751 This adds support for boards based on the STA2X11 IO-Hub, 752 a.k.a. "ConneXt". The chip is used in place of the standard 753 PC chipset, so all "standard" peripherals are missing. If this 754 option is selected the kernel will still be able to boot on 755 standard PC machines. 756 757config X86_32_IRIS 758 tristate "Eurobraille/Iris poweroff module" 759 depends on X86_32 760 help 761 The Iris machines from EuroBraille do not have APM or ACPI support 762 to shut themselves down properly. A special I/O sequence is 763 needed to do so, which is what this module does at 764 kernel shutdown. 765 766 This is only for Iris machines from EuroBraille. 767 768 If unused, say N. 769 770config SCHED_OMIT_FRAME_POINTER 771 def_bool y 772 prompt "Single-depth WCHAN output" 773 depends on X86 774 help 775 Calculate simpler /proc/<PID>/wchan values. If this option 776 is disabled then wchan values will recurse back to the 777 caller function. This provides more accurate wchan values, 778 at the expense of slightly more scheduling overhead. 779 780 If in doubt, say "Y". 781 782menuconfig HYPERVISOR_GUEST 783 bool "Linux guest support" 784 help 785 Say Y here to enable options for running Linux under various hyper- 786 visors. This option enables basic hypervisor detection and platform 787 setup. 788 789 If you say N, all options in this submenu will be skipped and 790 disabled, and Linux guest support won't be built in. 791 792if HYPERVISOR_GUEST 793 794config PARAVIRT 795 bool "Enable paravirtualization code" 796 depends on HAVE_STATIC_CALL 797 help 798 This changes the kernel so it can modify itself when it is run 799 under a hypervisor, potentially improving performance significantly 800 over full virtualization. However, when run without a hypervisor 801 the kernel is theoretically slower and slightly larger. 802 803config PARAVIRT_XXL 804 bool 805 806config PARAVIRT_DEBUG 807 bool "paravirt-ops debugging" 808 depends on PARAVIRT && DEBUG_KERNEL 809 help 810 Enable to debug paravirt_ops internals. Specifically, BUG if 811 a paravirt_op is missing when it is called. 812 813config PARAVIRT_SPINLOCKS 814 bool "Paravirtualization layer for spinlocks" 815 depends on PARAVIRT && SMP 816 help 817 Paravirtualized spinlocks allow a pvops backend to replace the 818 spinlock implementation with something virtualization-friendly 819 (for example, block the virtual CPU rather than spinning). 820 821 It has a minimal impact on native kernels and gives a nice performance 822 benefit on paravirtualized KVM / Xen kernels. 823 824 If you are unsure how to answer this question, answer Y. 825 826config X86_HV_CALLBACK_VECTOR 827 def_bool n 828 829source "arch/x86/xen/Kconfig" 830 831config KVM_GUEST 832 bool "KVM Guest support (including kvmclock)" 833 depends on PARAVIRT 834 select PARAVIRT_CLOCK 835 select ARCH_CPUIDLE_HALTPOLL 836 select X86_HV_CALLBACK_VECTOR 837 default y 838 help 839 This option enables various optimizations for running under the KVM 840 hypervisor. It includes a paravirtualized clock, so that instead 841 of relying on a PIT (or probably other) emulation by the 842 underlying device model, the host provides the guest with 843 timing infrastructure such as time of day, and system time 844 845config ARCH_CPUIDLE_HALTPOLL 846 def_bool n 847 prompt "Disable host haltpoll when loading haltpoll driver" 848 help 849 If virtualized under KVM, disable host haltpoll. 850 851config PVH 852 bool "Support for running PVH guests" 853 help 854 This option enables the PVH entry point for guest virtual machines 855 as specified in the x86/HVM direct boot ABI. 856 857config PARAVIRT_TIME_ACCOUNTING 858 bool "Paravirtual steal time accounting" 859 depends on PARAVIRT 860 help 861 Select this option to enable fine granularity task steal time 862 accounting. Time spent executing other tasks in parallel with 863 the current vCPU is discounted from the vCPU power. To account for 864 that, there can be a small performance impact. 865 866 If in doubt, say N here. 867 868config PARAVIRT_CLOCK 869 bool 870 871config JAILHOUSE_GUEST 872 bool "Jailhouse non-root cell support" 873 depends on X86_64 && PCI 874 select X86_PM_TIMER 875 help 876 This option allows to run Linux as guest in a Jailhouse non-root 877 cell. You can leave this option disabled if you only want to start 878 Jailhouse and run Linux afterwards in the root cell. 879 880config ACRN_GUEST 881 bool "ACRN Guest support" 882 depends on X86_64 883 select X86_HV_CALLBACK_VECTOR 884 help 885 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 886 a flexible, lightweight reference open-source hypervisor, built with 887 real-time and safety-criticality in mind. It is built for embedded 888 IOT with small footprint and real-time features. More details can be 889 found in https://projectacrn.org/. 890 891config INTEL_TDX_GUEST 892 bool "Intel TDX (Trust Domain Extensions) - Guest Support" 893 depends on X86_64 && CPU_SUP_INTEL 894 depends on X86_X2APIC 895 depends on EFI_STUB 896 select ARCH_HAS_CC_PLATFORM 897 select X86_MEM_ENCRYPT 898 select X86_MCE 899 select UNACCEPTED_MEMORY 900 help 901 Support running as a guest under Intel TDX. Without this support, 902 the guest kernel can not boot or run under TDX. 903 TDX includes memory encryption and integrity capabilities 904 which protect the confidentiality and integrity of guest 905 memory contents and CPU state. TDX guests are protected from 906 some attacks from the VMM. 907 908endif # HYPERVISOR_GUEST 909 910source "arch/x86/Kconfig.cpu" 911 912config HPET_TIMER 913 def_bool X86_64 914 prompt "HPET Timer Support" if X86_32 915 help 916 Use the IA-PC HPET (High Precision Event Timer) to manage 917 time in preference to the PIT and RTC, if a HPET is 918 present. 919 HPET is the next generation timer replacing legacy 8254s. 920 The HPET provides a stable time base on SMP 921 systems, unlike the TSC, but it is more expensive to access, 922 as it is off-chip. The interface used is documented 923 in the HPET spec, revision 1. 924 925 You can safely choose Y here. However, HPET will only be 926 activated if the platform and the BIOS support this feature. 927 Otherwise the 8254 will be used for timing services. 928 929 Choose N to continue using the legacy 8254 timer. 930 931config HPET_EMULATE_RTC 932 def_bool y 933 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 934 935# Mark as expert because too many people got it wrong. 936# The code disables itself when not needed. 937config DMI 938 default y 939 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 940 bool "Enable DMI scanning" if EXPERT 941 help 942 Enabled scanning of DMI to identify machine quirks. Say Y 943 here unless you have verified that your setup is not 944 affected by entries in the DMI blacklist. Required by PNP 945 BIOS code. 946 947config GART_IOMMU 948 bool "Old AMD GART IOMMU support" 949 select IOMMU_HELPER 950 select SWIOTLB 951 depends on X86_64 && PCI && AMD_NB 952 help 953 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 954 GART based hardware IOMMUs. 955 956 The GART supports full DMA access for devices with 32-bit access 957 limitations, on systems with more than 3 GB. This is usually needed 958 for USB, sound, many IDE/SATA chipsets and some other devices. 959 960 Newer systems typically have a modern AMD IOMMU, supported via 961 the CONFIG_AMD_IOMMU=y config option. 962 963 In normal configurations this driver is only active when needed: 964 there's more than 3 GB of memory and the system contains a 965 32-bit limited device. 966 967 If unsure, say Y. 968 969config BOOT_VESA_SUPPORT 970 bool 971 help 972 If true, at least one selected framebuffer driver can take advantage 973 of VESA video modes set at an early boot stage via the vga= parameter. 974 975config MAXSMP 976 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 977 depends on X86_64 && SMP && DEBUG_KERNEL 978 select CPUMASK_OFFSTACK 979 help 980 Enable maximum number of CPUS and NUMA Nodes for this architecture. 981 If unsure, say N. 982 983# 984# The maximum number of CPUs supported: 985# 986# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 987# and which can be configured interactively in the 988# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 989# 990# The ranges are different on 32-bit and 64-bit kernels, depending on 991# hardware capabilities and scalability features of the kernel. 992# 993# ( If MAXSMP is enabled we just use the highest possible value and disable 994# interactive configuration. ) 995# 996 997config NR_CPUS_RANGE_BEGIN 998 int 999 default NR_CPUS_RANGE_END if MAXSMP 1000 default 1 if !SMP 1001 default 2 1002 1003config NR_CPUS_RANGE_END 1004 int 1005 depends on X86_32 1006 default 64 if SMP && X86_BIGSMP 1007 default 8 if SMP && !X86_BIGSMP 1008 default 1 if !SMP 1009 1010config NR_CPUS_RANGE_END 1011 int 1012 depends on X86_64 1013 default 8192 if SMP && CPUMASK_OFFSTACK 1014 default 512 if SMP && !CPUMASK_OFFSTACK 1015 default 1 if !SMP 1016 1017config NR_CPUS_DEFAULT 1018 int 1019 depends on X86_32 1020 default 32 if X86_BIGSMP 1021 default 8 if SMP 1022 default 1 if !SMP 1023 1024config NR_CPUS_DEFAULT 1025 int 1026 depends on X86_64 1027 default 8192 if MAXSMP 1028 default 64 if SMP 1029 default 1 if !SMP 1030 1031config NR_CPUS 1032 int "Maximum number of CPUs" if SMP && !MAXSMP 1033 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1034 default NR_CPUS_DEFAULT 1035 help 1036 This allows you to specify the maximum number of CPUs which this 1037 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1038 supported value is 8192, otherwise the maximum value is 512. The 1039 minimum value which makes sense is 2. 1040 1041 This is purely to save memory: each supported CPU adds about 8KB 1042 to the kernel image. 1043 1044config SCHED_CLUSTER 1045 bool "Cluster scheduler support" 1046 depends on SMP 1047 default y 1048 help 1049 Cluster scheduler support improves the CPU scheduler's decision 1050 making when dealing with machines that have clusters of CPUs. 1051 Cluster usually means a couple of CPUs which are placed closely 1052 by sharing mid-level caches, last-level cache tags or internal 1053 busses. 1054 1055config SCHED_SMT 1056 def_bool y if SMP 1057 1058config SCHED_MC 1059 def_bool y 1060 prompt "Multi-core scheduler support" 1061 depends on SMP 1062 help 1063 Multi-core scheduler support improves the CPU scheduler's decision 1064 making when dealing with multi-core CPU chips at a cost of slightly 1065 increased overhead in some places. If unsure say N here. 1066 1067config SCHED_MC_PRIO 1068 bool "CPU core priorities scheduler support" 1069 depends on SCHED_MC 1070 select X86_INTEL_PSTATE if CPU_SUP_INTEL 1071 select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI 1072 select CPU_FREQ 1073 default y 1074 help 1075 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1076 core ordering determined at manufacturing time, which allows 1077 certain cores to reach higher turbo frequencies (when running 1078 single threaded workloads) than others. 1079 1080 Enabling this kernel feature teaches the scheduler about 1081 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1082 scheduler's CPU selection logic accordingly, so that higher 1083 overall system performance can be achieved. 1084 1085 This feature will have no effect on CPUs without this feature. 1086 1087 If unsure say Y here. 1088 1089config UP_LATE_INIT 1090 def_bool y 1091 depends on !SMP && X86_LOCAL_APIC 1092 1093config X86_UP_APIC 1094 bool "Local APIC support on uniprocessors" if !PCI_MSI 1095 default PCI_MSI 1096 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1097 help 1098 A local APIC (Advanced Programmable Interrupt Controller) is an 1099 integrated interrupt controller in the CPU. If you have a single-CPU 1100 system which has a processor with a local APIC, you can say Y here to 1101 enable and use it. If you say Y here even though your machine doesn't 1102 have a local APIC, then the kernel will still run with no slowdown at 1103 all. The local APIC supports CPU-generated self-interrupts (timer, 1104 performance counters), and the NMI watchdog which detects hard 1105 lockups. 1106 1107config X86_UP_IOAPIC 1108 bool "IO-APIC support on uniprocessors" 1109 depends on X86_UP_APIC 1110 help 1111 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1112 SMP-capable replacement for PC-style interrupt controllers. Most 1113 SMP systems and many recent uniprocessor systems have one. 1114 1115 If you have a single-CPU system with an IO-APIC, you can say Y here 1116 to use it. If you say Y here even though your machine doesn't have 1117 an IO-APIC, then the kernel will still run with no slowdown at all. 1118 1119config X86_LOCAL_APIC 1120 def_bool y 1121 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1122 select IRQ_DOMAIN_HIERARCHY 1123 1124config ACPI_MADT_WAKEUP 1125 def_bool y 1126 depends on X86_64 1127 depends on ACPI 1128 depends on SMP 1129 depends on X86_LOCAL_APIC 1130 1131config X86_IO_APIC 1132 def_bool y 1133 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1134 1135config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1136 bool "Reroute for broken boot IRQs" 1137 depends on X86_IO_APIC 1138 help 1139 This option enables a workaround that fixes a source of 1140 spurious interrupts. This is recommended when threaded 1141 interrupt handling is used on systems where the generation of 1142 superfluous "boot interrupts" cannot be disabled. 1143 1144 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1145 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1146 kernel does during interrupt handling). On chipsets where this 1147 boot IRQ generation cannot be disabled, this workaround keeps 1148 the original IRQ line masked so that only the equivalent "boot 1149 IRQ" is delivered to the CPUs. The workaround also tells the 1150 kernel to set up the IRQ handler on the boot IRQ line. In this 1151 way only one interrupt is delivered to the kernel. Otherwise 1152 the spurious second interrupt may cause the kernel to bring 1153 down (vital) interrupt lines. 1154 1155 Only affects "broken" chipsets. Interrupt sharing may be 1156 increased on these systems. 1157 1158config X86_MCE 1159 bool "Machine Check / overheating reporting" 1160 select GENERIC_ALLOCATOR 1161 default y 1162 help 1163 Machine Check support allows the processor to notify the 1164 kernel if it detects a problem (e.g. overheating, data corruption). 1165 The action the kernel takes depends on the severity of the problem, 1166 ranging from warning messages to halting the machine. 1167 1168config X86_MCELOG_LEGACY 1169 bool "Support for deprecated /dev/mcelog character device" 1170 depends on X86_MCE 1171 help 1172 Enable support for /dev/mcelog which is needed by the old mcelog 1173 userspace logging daemon. Consider switching to the new generation 1174 rasdaemon solution. 1175 1176config X86_MCE_INTEL 1177 def_bool y 1178 prompt "Intel MCE features" 1179 depends on X86_MCE && X86_LOCAL_APIC 1180 help 1181 Additional support for intel specific MCE features such as 1182 the thermal monitor. 1183 1184config X86_MCE_AMD 1185 def_bool y 1186 prompt "AMD MCE features" 1187 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1188 help 1189 Additional support for AMD specific MCE features such as 1190 the DRAM Error Threshold. 1191 1192config X86_ANCIENT_MCE 1193 bool "Support for old Pentium 5 / WinChip machine checks" 1194 depends on X86_32 && X86_MCE 1195 help 1196 Include support for machine check handling on old Pentium 5 or WinChip 1197 systems. These typically need to be enabled explicitly on the command 1198 line. 1199 1200config X86_MCE_THRESHOLD 1201 depends on X86_MCE_AMD || X86_MCE_INTEL 1202 def_bool y 1203 1204config X86_MCE_INJECT 1205 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1206 tristate "Machine check injector support" 1207 help 1208 Provide support for injecting machine checks for testing purposes. 1209 If you don't know what a machine check is and you don't do kernel 1210 QA it is safe to say n. 1211 1212source "arch/x86/events/Kconfig" 1213 1214config X86_LEGACY_VM86 1215 bool "Legacy VM86 support" 1216 depends on X86_32 1217 help 1218 This option allows user programs to put the CPU into V8086 1219 mode, which is an 80286-era approximation of 16-bit real mode. 1220 1221 Some very old versions of X and/or vbetool require this option 1222 for user mode setting. Similarly, DOSEMU will use it if 1223 available to accelerate real mode DOS programs. However, any 1224 recent version of DOSEMU, X, or vbetool should be fully 1225 functional even without kernel VM86 support, as they will all 1226 fall back to software emulation. Nevertheless, if you are using 1227 a 16-bit DOS program where 16-bit performance matters, vm86 1228 mode might be faster than emulation and you might want to 1229 enable this option. 1230 1231 Note that any app that works on a 64-bit kernel is unlikely to 1232 need this option, as 64-bit kernels don't, and can't, support 1233 V8086 mode. This option is also unrelated to 16-bit protected 1234 mode and is not needed to run most 16-bit programs under Wine. 1235 1236 Enabling this option increases the complexity of the kernel 1237 and slows down exception handling a tiny bit. 1238 1239 If unsure, say N here. 1240 1241config VM86 1242 bool 1243 default X86_LEGACY_VM86 1244 1245config X86_16BIT 1246 bool "Enable support for 16-bit segments" if EXPERT 1247 default y 1248 depends on MODIFY_LDT_SYSCALL 1249 help 1250 This option is required by programs like Wine to run 16-bit 1251 protected mode legacy code on x86 processors. Disabling 1252 this option saves about 300 bytes on i386, or around 6K text 1253 plus 16K runtime memory on x86-64, 1254 1255config X86_ESPFIX32 1256 def_bool y 1257 depends on X86_16BIT && X86_32 1258 1259config X86_ESPFIX64 1260 def_bool y 1261 depends on X86_16BIT && X86_64 1262 1263config X86_VSYSCALL_EMULATION 1264 bool "Enable vsyscall emulation" if EXPERT 1265 default y 1266 depends on X86_64 1267 help 1268 This enables emulation of the legacy vsyscall page. Disabling 1269 it is roughly equivalent to booting with vsyscall=none, except 1270 that it will also disable the helpful warning if a program 1271 tries to use a vsyscall. With this option set to N, offending 1272 programs will just segfault, citing addresses of the form 1273 0xffffffffff600?00. 1274 1275 This option is required by many programs built before 2013, and 1276 care should be used even with newer programs if set to N. 1277 1278 Disabling this option saves about 7K of kernel size and 1279 possibly 4K of additional runtime pagetable memory. 1280 1281config X86_IOPL_IOPERM 1282 bool "IOPERM and IOPL Emulation" 1283 default y 1284 help 1285 This enables the ioperm() and iopl() syscalls which are necessary 1286 for legacy applications. 1287 1288 Legacy IOPL support is an overbroad mechanism which allows user 1289 space aside of accessing all 65536 I/O ports also to disable 1290 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1291 capabilities and permission from potentially active security 1292 modules. 1293 1294 The emulation restricts the functionality of the syscall to 1295 only allowing the full range I/O port access, but prevents the 1296 ability to disable interrupts from user space which would be 1297 granted if the hardware IOPL mechanism would be used. 1298 1299config TOSHIBA 1300 tristate "Toshiba Laptop support" 1301 depends on X86_32 1302 help 1303 This adds a driver to safely access the System Management Mode of 1304 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1305 not work on models with a Phoenix BIOS. The System Management Mode 1306 is used to set the BIOS and power saving options on Toshiba portables. 1307 1308 For information on utilities to make use of this driver see the 1309 Toshiba Linux utilities web site at: 1310 <http://www.buzzard.org.uk/toshiba/>. 1311 1312 Say Y if you intend to run this kernel on a Toshiba portable. 1313 Say N otherwise. 1314 1315config X86_REBOOTFIXUPS 1316 bool "Enable X86 board specific fixups for reboot" 1317 depends on X86_32 1318 help 1319 This enables chipset and/or board specific fixups to be done 1320 in order to get reboot to work correctly. This is only needed on 1321 some combinations of hardware and BIOS. The symptom, for which 1322 this config is intended, is when reboot ends with a stalled/hung 1323 system. 1324 1325 Currently, the only fixup is for the Geode machines using 1326 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1327 1328 Say Y if you want to enable the fixup. Currently, it's safe to 1329 enable this option even if you don't need it. 1330 Say N otherwise. 1331 1332config MICROCODE 1333 def_bool y 1334 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1335 1336config MICROCODE_INITRD32 1337 def_bool y 1338 depends on MICROCODE && X86_32 && BLK_DEV_INITRD 1339 1340config MICROCODE_LATE_LOADING 1341 bool "Late microcode loading (DANGEROUS)" 1342 default n 1343 depends on MICROCODE && SMP 1344 help 1345 Loading microcode late, when the system is up and executing instructions 1346 is a tricky business and should be avoided if possible. Just the sequence 1347 of synchronizing all cores and SMT threads is one fragile dance which does 1348 not guarantee that cores might not softlock after the loading. Therefore, 1349 use this at your own risk. Late loading taints the kernel unless the 1350 microcode header indicates that it is safe for late loading via the 1351 minimal revision check. This minimal revision check can be enforced on 1352 the kernel command line with "microcode.minrev=Y". 1353 1354config MICROCODE_LATE_FORCE_MINREV 1355 bool "Enforce late microcode loading minimal revision check" 1356 default n 1357 depends on MICROCODE_LATE_LOADING 1358 help 1359 To prevent that users load microcode late which modifies already 1360 in use features, newer microcode patches have a minimum revision field 1361 in the microcode header, which tells the kernel which minimum 1362 revision must be active in the CPU to safely load that new microcode 1363 late into the running system. If disabled the check will not 1364 be enforced but the kernel will be tainted when the minimal 1365 revision check fails. 1366 1367 This minimal revision check can also be controlled via the 1368 "microcode.minrev" parameter on the kernel command line. 1369 1370 If unsure say Y. 1371 1372config X86_MSR 1373 tristate "/dev/cpu/*/msr - Model-specific register support" 1374 help 1375 This device gives privileged processes access to the x86 1376 Model-Specific Registers (MSRs). It is a character device with 1377 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1378 MSR accesses are directed to a specific CPU on multi-processor 1379 systems. 1380 1381config X86_CPUID 1382 tristate "/dev/cpu/*/cpuid - CPU information support" 1383 help 1384 This device gives processes access to the x86 CPUID instruction to 1385 be executed on a specific processor. It is a character device 1386 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1387 /dev/cpu/31/cpuid. 1388 1389choice 1390 prompt "High Memory Support" 1391 default HIGHMEM4G 1392 depends on X86_32 1393 1394config NOHIGHMEM 1395 bool "off" 1396 help 1397 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1398 However, the address space of 32-bit x86 processors is only 4 1399 Gigabytes large. That means that, if you have a large amount of 1400 physical memory, not all of it can be "permanently mapped" by the 1401 kernel. The physical memory that's not permanently mapped is called 1402 "high memory". 1403 1404 If you are compiling a kernel which will never run on a machine with 1405 more than 1 Gigabyte total physical RAM, answer "off" here (default 1406 choice and suitable for most users). This will result in a "3GB/1GB" 1407 split: 3GB are mapped so that each process sees a 3GB virtual memory 1408 space and the remaining part of the 4GB virtual memory space is used 1409 by the kernel to permanently map as much physical memory as 1410 possible. 1411 1412 If the machine has between 1 and 4 Gigabytes physical RAM, then 1413 answer "4GB" here. 1414 1415 If more than 4 Gigabytes is used then answer "64GB" here. This 1416 selection turns Intel PAE (Physical Address Extension) mode on. 1417 PAE implements 3-level paging on IA32 processors. PAE is fully 1418 supported by Linux, PAE mode is implemented on all recent Intel 1419 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1420 then the kernel will not boot on CPUs that don't support PAE! 1421 1422 The actual amount of total physical memory will either be 1423 auto detected or can be forced by using a kernel command line option 1424 such as "mem=256M". (Try "man bootparam" or see the documentation of 1425 your boot loader (lilo or loadlin) about how to pass options to the 1426 kernel at boot time.) 1427 1428 If unsure, say "off". 1429 1430config HIGHMEM4G 1431 bool "4GB" 1432 help 1433 Select this if you have a 32-bit processor and between 1 and 4 1434 gigabytes of physical RAM. 1435 1436config HIGHMEM64G 1437 bool "64GB" 1438 depends on X86_HAVE_PAE 1439 select X86_PAE 1440 help 1441 Select this if you have a 32-bit processor and more than 4 1442 gigabytes of physical RAM. 1443 1444endchoice 1445 1446choice 1447 prompt "Memory split" if EXPERT 1448 default VMSPLIT_3G 1449 depends on X86_32 1450 help 1451 Select the desired split between kernel and user memory. 1452 1453 If the address range available to the kernel is less than the 1454 physical memory installed, the remaining memory will be available 1455 as "high memory". Accessing high memory is a little more costly 1456 than low memory, as it needs to be mapped into the kernel first. 1457 Note that increasing the kernel address space limits the range 1458 available to user programs, making the address space there 1459 tighter. Selecting anything other than the default 3G/1G split 1460 will also likely make your kernel incompatible with binary-only 1461 kernel modules. 1462 1463 If you are not absolutely sure what you are doing, leave this 1464 option alone! 1465 1466 config VMSPLIT_3G 1467 bool "3G/1G user/kernel split" 1468 config VMSPLIT_3G_OPT 1469 depends on !X86_PAE 1470 bool "3G/1G user/kernel split (for full 1G low memory)" 1471 config VMSPLIT_2G 1472 bool "2G/2G user/kernel split" 1473 config VMSPLIT_2G_OPT 1474 depends on !X86_PAE 1475 bool "2G/2G user/kernel split (for full 2G low memory)" 1476 config VMSPLIT_1G 1477 bool "1G/3G user/kernel split" 1478endchoice 1479 1480config PAGE_OFFSET 1481 hex 1482 default 0xB0000000 if VMSPLIT_3G_OPT 1483 default 0x80000000 if VMSPLIT_2G 1484 default 0x78000000 if VMSPLIT_2G_OPT 1485 default 0x40000000 if VMSPLIT_1G 1486 default 0xC0000000 1487 depends on X86_32 1488 1489config HIGHMEM 1490 def_bool y 1491 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1492 1493config X86_PAE 1494 bool "PAE (Physical Address Extension) Support" 1495 depends on X86_32 && X86_HAVE_PAE 1496 select PHYS_ADDR_T_64BIT 1497 select SWIOTLB 1498 help 1499 PAE is required for NX support, and furthermore enables 1500 larger swapspace support for non-overcommit purposes. It 1501 has the cost of more pagetable lookup overhead, and also 1502 consumes more pagetable space per process. 1503 1504config X86_5LEVEL 1505 bool "Enable 5-level page tables support" 1506 default y 1507 select DYNAMIC_MEMORY_LAYOUT 1508 select SPARSEMEM_VMEMMAP 1509 depends on X86_64 1510 help 1511 5-level paging enables access to larger address space: 1512 up to 128 PiB of virtual address space and 4 PiB of 1513 physical address space. 1514 1515 It will be supported by future Intel CPUs. 1516 1517 A kernel with the option enabled can be booted on machines that 1518 support 4- or 5-level paging. 1519 1520 See Documentation/arch/x86/x86_64/5level-paging.rst for more 1521 information. 1522 1523 Say N if unsure. 1524 1525config X86_DIRECT_GBPAGES 1526 def_bool y 1527 depends on X86_64 1528 help 1529 Certain kernel features effectively disable kernel 1530 linear 1 GB mappings (even if the CPU otherwise 1531 supports them), so don't confuse the user by printing 1532 that we have them enabled. 1533 1534config X86_CPA_STATISTICS 1535 bool "Enable statistic for Change Page Attribute" 1536 depends on DEBUG_FS 1537 help 1538 Expose statistics about the Change Page Attribute mechanism, which 1539 helps to determine the effectiveness of preserving large and huge 1540 page mappings when mapping protections are changed. 1541 1542config X86_MEM_ENCRYPT 1543 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1544 select DYNAMIC_PHYSICAL_MASK 1545 def_bool n 1546 1547config AMD_MEM_ENCRYPT 1548 bool "AMD Secure Memory Encryption (SME) support" 1549 depends on X86_64 && CPU_SUP_AMD 1550 depends on EFI_STUB 1551 select DMA_COHERENT_POOL 1552 select ARCH_USE_MEMREMAP_PROT 1553 select INSTRUCTION_DECODER 1554 select ARCH_HAS_CC_PLATFORM 1555 select X86_MEM_ENCRYPT 1556 select UNACCEPTED_MEMORY 1557 help 1558 Say yes to enable support for the encryption of system memory. 1559 This requires an AMD processor that supports Secure Memory 1560 Encryption (SME). 1561 1562# Common NUMA Features 1563config NUMA 1564 bool "NUMA Memory Allocation and Scheduler Support" 1565 depends on SMP 1566 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1567 default y if X86_BIGSMP 1568 select USE_PERCPU_NUMA_NODE_ID 1569 select OF_NUMA if OF 1570 help 1571 Enable NUMA (Non-Uniform Memory Access) support. 1572 1573 The kernel will try to allocate memory used by a CPU on the 1574 local memory controller of the CPU and add some more 1575 NUMA awareness to the kernel. 1576 1577 For 64-bit this is recommended if the system is Intel Core i7 1578 (or later), AMD Opteron, or EM64T NUMA. 1579 1580 For 32-bit this is only needed if you boot a 32-bit 1581 kernel on a 64-bit NUMA platform. 1582 1583 Otherwise, you should say N. 1584 1585config AMD_NUMA 1586 def_bool y 1587 prompt "Old style AMD Opteron NUMA detection" 1588 depends on X86_64 && NUMA && PCI 1589 help 1590 Enable AMD NUMA node topology detection. You should say Y here if 1591 you have a multi processor AMD system. This uses an old method to 1592 read the NUMA configuration directly from the builtin Northbridge 1593 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1594 which also takes priority if both are compiled in. 1595 1596config X86_64_ACPI_NUMA 1597 def_bool y 1598 prompt "ACPI NUMA detection" 1599 depends on X86_64 && NUMA && ACPI && PCI 1600 select ACPI_NUMA 1601 help 1602 Enable ACPI SRAT based node topology detection. 1603 1604config NUMA_EMU 1605 bool "NUMA emulation" 1606 depends on NUMA 1607 help 1608 Enable NUMA emulation. A flat machine will be split 1609 into virtual nodes when booted with "numa=fake=N", where N is the 1610 number of nodes. This is only useful for debugging. 1611 1612config NODES_SHIFT 1613 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1614 range 1 10 1615 default "10" if MAXSMP 1616 default "6" if X86_64 1617 default "3" 1618 depends on NUMA 1619 help 1620 Specify the maximum number of NUMA Nodes available on the target 1621 system. Increases memory reserved to accommodate various tables. 1622 1623config ARCH_FLATMEM_ENABLE 1624 def_bool y 1625 depends on X86_32 && !NUMA 1626 1627config ARCH_SPARSEMEM_ENABLE 1628 def_bool y 1629 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1630 select SPARSEMEM_STATIC if X86_32 1631 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1632 1633config ARCH_SPARSEMEM_DEFAULT 1634 def_bool X86_64 || (NUMA && X86_32) 1635 1636config ARCH_SELECT_MEMORY_MODEL 1637 def_bool y 1638 depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1639 1640config ARCH_MEMORY_PROBE 1641 bool "Enable sysfs memory/probe interface" 1642 depends on MEMORY_HOTPLUG 1643 help 1644 This option enables a sysfs memory/probe interface for testing. 1645 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1646 If you are unsure how to answer this question, answer N. 1647 1648config ARCH_PROC_KCORE_TEXT 1649 def_bool y 1650 depends on X86_64 && PROC_KCORE 1651 1652config ILLEGAL_POINTER_VALUE 1653 hex 1654 default 0 if X86_32 1655 default 0xdead000000000000 if X86_64 1656 1657config X86_PMEM_LEGACY_DEVICE 1658 bool 1659 1660config X86_PMEM_LEGACY 1661 tristate "Support non-standard NVDIMMs and ADR protected memory" 1662 depends on PHYS_ADDR_T_64BIT 1663 depends on BLK_DEV 1664 select X86_PMEM_LEGACY_DEVICE 1665 select NUMA_KEEP_MEMINFO if NUMA 1666 select LIBNVDIMM 1667 help 1668 Treat memory marked using the non-standard e820 type of 12 as used 1669 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1670 The kernel will offer these regions to the 'pmem' driver so 1671 they can be used for persistent storage. 1672 1673 Say Y if unsure. 1674 1675config HIGHPTE 1676 bool "Allocate 3rd-level pagetables from highmem" 1677 depends on HIGHMEM 1678 help 1679 The VM uses one page table entry for each page of physical memory. 1680 For systems with a lot of RAM, this can be wasteful of precious 1681 low memory. Setting this option will put user-space page table 1682 entries in high memory. 1683 1684config X86_CHECK_BIOS_CORRUPTION 1685 bool "Check for low memory corruption" 1686 help 1687 Periodically check for memory corruption in low memory, which 1688 is suspected to be caused by BIOS. Even when enabled in the 1689 configuration, it is disabled at runtime. Enable it by 1690 setting "memory_corruption_check=1" on the kernel command 1691 line. By default it scans the low 64k of memory every 60 1692 seconds; see the memory_corruption_check_size and 1693 memory_corruption_check_period parameters in 1694 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1695 1696 When enabled with the default parameters, this option has 1697 almost no overhead, as it reserves a relatively small amount 1698 of memory and scans it infrequently. It both detects corruption 1699 and prevents it from affecting the running system. 1700 1701 It is, however, intended as a diagnostic tool; if repeatable 1702 BIOS-originated corruption always affects the same memory, 1703 you can use memmap= to prevent the kernel from using that 1704 memory. 1705 1706config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1707 bool "Set the default setting of memory_corruption_check" 1708 depends on X86_CHECK_BIOS_CORRUPTION 1709 default y 1710 help 1711 Set whether the default state of memory_corruption_check is 1712 on or off. 1713 1714config MATH_EMULATION 1715 bool 1716 depends on MODIFY_LDT_SYSCALL 1717 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1718 help 1719 Linux can emulate a math coprocessor (used for floating point 1720 operations) if you don't have one. 486DX and Pentium processors have 1721 a math coprocessor built in, 486SX and 386 do not, unless you added 1722 a 487DX or 387, respectively. (The messages during boot time can 1723 give you some hints here ["man dmesg"].) Everyone needs either a 1724 coprocessor or this emulation. 1725 1726 If you don't have a math coprocessor, you need to say Y here; if you 1727 say Y here even though you have a coprocessor, the coprocessor will 1728 be used nevertheless. (This behavior can be changed with the kernel 1729 command line option "no387", which comes handy if your coprocessor 1730 is broken. Try "man bootparam" or see the documentation of your boot 1731 loader (lilo or loadlin) about how to pass options to the kernel at 1732 boot time.) This means that it is a good idea to say Y here if you 1733 intend to use this kernel on different machines. 1734 1735 More information about the internals of the Linux math coprocessor 1736 emulation can be found in <file:arch/x86/math-emu/README>. 1737 1738 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1739 kernel, it won't hurt. 1740 1741config MTRR 1742 def_bool y 1743 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1744 help 1745 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1746 the Memory Type Range Registers (MTRRs) may be used to control 1747 processor access to memory ranges. This is most useful if you have 1748 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1749 allows bus write transfers to be combined into a larger transfer 1750 before bursting over the PCI/AGP bus. This can increase performance 1751 of image write operations 2.5 times or more. Saying Y here creates a 1752 /proc/mtrr file which may be used to manipulate your processor's 1753 MTRRs. Typically the X server should use this. 1754 1755 This code has a reasonably generic interface so that similar 1756 control registers on other processors can be easily supported 1757 as well: 1758 1759 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1760 Registers (ARRs) which provide a similar functionality to MTRRs. For 1761 these, the ARRs are used to emulate the MTRRs. 1762 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1763 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1764 write-combining. All of these processors are supported by this code 1765 and it makes sense to say Y here if you have one of them. 1766 1767 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1768 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1769 can lead to all sorts of problems, so it's good to say Y here. 1770 1771 You can safely say Y even if your machine doesn't have MTRRs, you'll 1772 just add about 9 KB to your kernel. 1773 1774 See <file:Documentation/arch/x86/mtrr.rst> for more information. 1775 1776config MTRR_SANITIZER 1777 def_bool y 1778 prompt "MTRR cleanup support" 1779 depends on MTRR 1780 help 1781 Convert MTRR layout from continuous to discrete, so X drivers can 1782 add writeback entries. 1783 1784 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1785 The largest mtrr entry size for a continuous block can be set with 1786 mtrr_chunk_size. 1787 1788 If unsure, say Y. 1789 1790config MTRR_SANITIZER_ENABLE_DEFAULT 1791 int "MTRR cleanup enable value (0-1)" 1792 range 0 1 1793 default "0" 1794 depends on MTRR_SANITIZER 1795 help 1796 Enable mtrr cleanup default value 1797 1798config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1799 int "MTRR cleanup spare reg num (0-7)" 1800 range 0 7 1801 default "1" 1802 depends on MTRR_SANITIZER 1803 help 1804 mtrr cleanup spare entries default, it can be changed via 1805 mtrr_spare_reg_nr=N on the kernel command line. 1806 1807config X86_PAT 1808 def_bool y 1809 prompt "x86 PAT support" if EXPERT 1810 depends on MTRR 1811 help 1812 Use PAT attributes to setup page level cache control. 1813 1814 PATs are the modern equivalents of MTRRs and are much more 1815 flexible than MTRRs. 1816 1817 Say N here if you see bootup problems (boot crash, boot hang, 1818 spontaneous reboots) or a non-working video driver. 1819 1820 If unsure, say Y. 1821 1822config ARCH_USES_PG_UNCACHED 1823 def_bool y 1824 depends on X86_PAT 1825 1826config X86_UMIP 1827 def_bool y 1828 prompt "User Mode Instruction Prevention" if EXPERT 1829 help 1830 User Mode Instruction Prevention (UMIP) is a security feature in 1831 some x86 processors. If enabled, a general protection fault is 1832 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1833 executed in user mode. These instructions unnecessarily expose 1834 information about the hardware state. 1835 1836 The vast majority of applications do not use these instructions. 1837 For the very few that do, software emulation is provided in 1838 specific cases in protected and virtual-8086 modes. Emulated 1839 results are dummy. 1840 1841config CC_HAS_IBT 1842 # GCC >= 9 and binutils >= 2.29 1843 # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1844 # Clang/LLVM >= 14 1845 # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1846 # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1847 def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1848 (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1849 $(as-instr,endbr64) 1850 1851config X86_CET 1852 def_bool n 1853 help 1854 CET features configured (Shadow stack or IBT) 1855 1856config X86_KERNEL_IBT 1857 prompt "Indirect Branch Tracking" 1858 def_bool y 1859 depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1860 # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1861 depends on !LD_IS_LLD || LLD_VERSION >= 140000 1862 select OBJTOOL 1863 select X86_CET 1864 help 1865 Build the kernel with support for Indirect Branch Tracking, a 1866 hardware support course-grain forward-edge Control Flow Integrity 1867 protection. It enforces that all indirect calls must land on 1868 an ENDBR instruction, as such, the compiler will instrument the 1869 code with them to make this happen. 1870 1871 In addition to building the kernel with IBT, seal all functions that 1872 are not indirect call targets, avoiding them ever becoming one. 1873 1874 This requires LTO like objtool runs and will slow down the build. It 1875 does significantly reduce the number of ENDBR instructions in the 1876 kernel image. 1877 1878config X86_INTEL_MEMORY_PROTECTION_KEYS 1879 prompt "Memory Protection Keys" 1880 def_bool y 1881 # Note: only available in 64-bit mode 1882 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1883 select ARCH_USES_HIGH_VMA_FLAGS 1884 select ARCH_HAS_PKEYS 1885 help 1886 Memory Protection Keys provides a mechanism for enforcing 1887 page-based protections, but without requiring modification of the 1888 page tables when an application changes protection domains. 1889 1890 For details, see Documentation/core-api/protection-keys.rst 1891 1892 If unsure, say y. 1893 1894config ARCH_PKEY_BITS 1895 int 1896 default 4 1897 1898choice 1899 prompt "TSX enable mode" 1900 depends on CPU_SUP_INTEL 1901 default X86_INTEL_TSX_MODE_OFF 1902 help 1903 Intel's TSX (Transactional Synchronization Extensions) feature 1904 allows to optimize locking protocols through lock elision which 1905 can lead to a noticeable performance boost. 1906 1907 On the other hand it has been shown that TSX can be exploited 1908 to form side channel attacks (e.g. TAA) and chances are there 1909 will be more of those attacks discovered in the future. 1910 1911 Therefore TSX is not enabled by default (aka tsx=off). An admin 1912 might override this decision by tsx=on the command line parameter. 1913 Even with TSX enabled, the kernel will attempt to enable the best 1914 possible TAA mitigation setting depending on the microcode available 1915 for the particular machine. 1916 1917 This option allows to set the default tsx mode between tsx=on, =off 1918 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1919 details. 1920 1921 Say off if not sure, auto if TSX is in use but it should be used on safe 1922 platforms or on if TSX is in use and the security aspect of tsx is not 1923 relevant. 1924 1925config X86_INTEL_TSX_MODE_OFF 1926 bool "off" 1927 help 1928 TSX is disabled if possible - equals to tsx=off command line parameter. 1929 1930config X86_INTEL_TSX_MODE_ON 1931 bool "on" 1932 help 1933 TSX is always enabled on TSX capable HW - equals the tsx=on command 1934 line parameter. 1935 1936config X86_INTEL_TSX_MODE_AUTO 1937 bool "auto" 1938 help 1939 TSX is enabled on TSX capable HW that is believed to be safe against 1940 side channel attacks- equals the tsx=auto command line parameter. 1941endchoice 1942 1943config X86_SGX 1944 bool "Software Guard eXtensions (SGX)" 1945 depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC 1946 depends on CRYPTO=y 1947 depends on CRYPTO_SHA256=y 1948 select MMU_NOTIFIER 1949 select NUMA_KEEP_MEMINFO if NUMA 1950 select XARRAY_MULTI 1951 help 1952 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1953 that can be used by applications to set aside private regions of code 1954 and data, referred to as enclaves. An enclave's private memory can 1955 only be accessed by code running within the enclave. Accesses from 1956 outside the enclave, including other enclaves, are disallowed by 1957 hardware. 1958 1959 If unsure, say N. 1960 1961config X86_USER_SHADOW_STACK 1962 bool "X86 userspace shadow stack" 1963 depends on AS_WRUSS 1964 depends on X86_64 1965 select ARCH_USES_HIGH_VMA_FLAGS 1966 select X86_CET 1967 help 1968 Shadow stack protection is a hardware feature that detects function 1969 return address corruption. This helps mitigate ROP attacks. 1970 Applications must be enabled to use it, and old userspace does not 1971 get protection "for free". 1972 1973 CPUs supporting shadow stacks were first released in 2020. 1974 1975 See Documentation/arch/x86/shstk.rst for more information. 1976 1977 If unsure, say N. 1978 1979config INTEL_TDX_HOST 1980 bool "Intel Trust Domain Extensions (TDX) host support" 1981 depends on CPU_SUP_INTEL 1982 depends on X86_64 1983 depends on KVM_INTEL 1984 depends on X86_X2APIC 1985 select ARCH_KEEP_MEMBLOCK 1986 depends on CONTIG_ALLOC 1987 depends on !KEXEC_CORE 1988 depends on X86_MCE 1989 help 1990 Intel Trust Domain Extensions (TDX) protects guest VMs from malicious 1991 host and certain physical attacks. This option enables necessary TDX 1992 support in the host kernel to run confidential VMs. 1993 1994 If unsure, say N. 1995 1996config EFI 1997 bool "EFI runtime service support" 1998 depends on ACPI 1999 select UCS2_STRING 2000 select EFI_RUNTIME_WRAPPERS 2001 select ARCH_USE_MEMREMAP_PROT 2002 select EFI_RUNTIME_MAP if KEXEC_CORE 2003 help 2004 This enables the kernel to use EFI runtime services that are 2005 available (such as the EFI variable services). 2006 2007 This option is only useful on systems that have EFI firmware. 2008 In addition, you should use the latest ELILO loader available 2009 at <http://elilo.sourceforge.net> in order to take advantage 2010 of EFI runtime services. However, even with this option, the 2011 resultant kernel should continue to boot on existing non-EFI 2012 platforms. 2013 2014config EFI_STUB 2015 bool "EFI stub support" 2016 depends on EFI 2017 select RELOCATABLE 2018 help 2019 This kernel feature allows a bzImage to be loaded directly 2020 by EFI firmware without the use of a bootloader. 2021 2022 See Documentation/admin-guide/efi-stub.rst for more information. 2023 2024config EFI_HANDOVER_PROTOCOL 2025 bool "EFI handover protocol (DEPRECATED)" 2026 depends on EFI_STUB 2027 default y 2028 help 2029 Select this in order to include support for the deprecated EFI 2030 handover protocol, which defines alternative entry points into the 2031 EFI stub. This is a practice that has no basis in the UEFI 2032 specification, and requires a priori knowledge on the part of the 2033 bootloader about Linux/x86 specific ways of passing the command line 2034 and initrd, and where in memory those assets may be loaded. 2035 2036 If in doubt, say Y. Even though the corresponding support is not 2037 present in upstream GRUB or other bootloaders, most distros build 2038 GRUB with numerous downstream patches applied, and may rely on the 2039 handover protocol as as result. 2040 2041config EFI_MIXED 2042 bool "EFI mixed-mode support" 2043 depends on EFI_STUB && X86_64 2044 help 2045 Enabling this feature allows a 64-bit kernel to be booted 2046 on a 32-bit firmware, provided that your CPU supports 64-bit 2047 mode. 2048 2049 Note that it is not possible to boot a mixed-mode enabled 2050 kernel via the EFI boot stub - a bootloader that supports 2051 the EFI handover protocol must be used. 2052 2053 If unsure, say N. 2054 2055config EFI_RUNTIME_MAP 2056 bool "Export EFI runtime maps to sysfs" if EXPERT 2057 depends on EFI 2058 help 2059 Export EFI runtime memory regions to /sys/firmware/efi/runtime-map. 2060 That memory map is required by the 2nd kernel to set up EFI virtual 2061 mappings after kexec, but can also be used for debugging purposes. 2062 2063 See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. 2064 2065source "kernel/Kconfig.hz" 2066 2067config ARCH_SUPPORTS_KEXEC 2068 def_bool y 2069 2070config ARCH_SUPPORTS_KEXEC_FILE 2071 def_bool X86_64 2072 2073config ARCH_SELECTS_KEXEC_FILE 2074 def_bool y 2075 depends on KEXEC_FILE 2076 select HAVE_IMA_KEXEC if IMA 2077 2078config ARCH_SUPPORTS_KEXEC_PURGATORY 2079 def_bool y 2080 2081config ARCH_SUPPORTS_KEXEC_SIG 2082 def_bool y 2083 2084config ARCH_SUPPORTS_KEXEC_SIG_FORCE 2085 def_bool y 2086 2087config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG 2088 def_bool y 2089 2090config ARCH_SUPPORTS_KEXEC_JUMP 2091 def_bool y 2092 2093config ARCH_SUPPORTS_CRASH_DUMP 2094 def_bool X86_64 || (X86_32 && HIGHMEM) 2095 2096config ARCH_SUPPORTS_CRASH_HOTPLUG 2097 def_bool y 2098 2099config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION 2100 def_bool CRASH_RESERVE 2101 2102config PHYSICAL_START 2103 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2104 default "0x1000000" 2105 help 2106 This gives the physical address where the kernel is loaded. 2107 2108 If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage 2109 will decompress itself to above physical address and run from there. 2110 Otherwise, bzImage will run from the address where it has been loaded 2111 by the boot loader. The only exception is if it is loaded below the 2112 above physical address, in which case it will relocate itself there. 2113 2114 In normal kdump cases one does not have to set/change this option 2115 as now bzImage can be compiled as a completely relocatable image 2116 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2117 address. This option is mainly useful for the folks who don't want 2118 to use a bzImage for capturing the crash dump and want to use a 2119 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2120 to be specifically compiled to run from a specific memory area 2121 (normally a reserved region) and this option comes handy. 2122 2123 So if you are using bzImage for capturing the crash dump, 2124 leave the value here unchanged to 0x1000000 and set 2125 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2126 for capturing the crash dump change this value to start of 2127 the reserved region. In other words, it can be set based on 2128 the "X" value as specified in the "crashkernel=YM@XM" 2129 command line boot parameter passed to the panic-ed 2130 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2131 for more details about crash dumps. 2132 2133 Usage of bzImage for capturing the crash dump is recommended as 2134 one does not have to build two kernels. Same kernel can be used 2135 as production kernel and capture kernel. Above option should have 2136 gone away after relocatable bzImage support is introduced. But it 2137 is present because there are users out there who continue to use 2138 vmlinux for dump capture. This option should go away down the 2139 line. 2140 2141 Don't change this unless you know what you are doing. 2142 2143config RELOCATABLE 2144 bool "Build a relocatable kernel" 2145 default y 2146 help 2147 This builds a kernel image that retains relocation information 2148 so it can be loaded someplace besides the default 1MB. 2149 The relocations tend to make the kernel binary about 10% larger, 2150 but are discarded at runtime. 2151 2152 One use is for the kexec on panic case where the recovery kernel 2153 must live at a different physical address than the primary 2154 kernel. 2155 2156 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2157 it has been loaded at and the compile time physical address 2158 (CONFIG_PHYSICAL_START) is used as the minimum location. 2159 2160config RANDOMIZE_BASE 2161 bool "Randomize the address of the kernel image (KASLR)" 2162 depends on RELOCATABLE 2163 default y 2164 help 2165 In support of Kernel Address Space Layout Randomization (KASLR), 2166 this randomizes the physical address at which the kernel image 2167 is decompressed and the virtual address where the kernel 2168 image is mapped, as a security feature that deters exploit 2169 attempts relying on knowledge of the location of kernel 2170 code internals. 2171 2172 On 64-bit, the kernel physical and virtual addresses are 2173 randomized separately. The physical address will be anywhere 2174 between 16MB and the top of physical memory (up to 64TB). The 2175 virtual address will be randomized from 16MB up to 1GB (9 bits 2176 of entropy). Note that this also reduces the memory space 2177 available to kernel modules from 1.5GB to 1GB. 2178 2179 On 32-bit, the kernel physical and virtual addresses are 2180 randomized together. They will be randomized from 16MB up to 2181 512MB (8 bits of entropy). 2182 2183 Entropy is generated using the RDRAND instruction if it is 2184 supported. If RDTSC is supported, its value is mixed into 2185 the entropy pool as well. If neither RDRAND nor RDTSC are 2186 supported, then entropy is read from the i8254 timer. The 2187 usable entropy is limited by the kernel being built using 2188 2GB addressing, and that PHYSICAL_ALIGN must be at a 2189 minimum of 2MB. As a result, only 10 bits of entropy are 2190 theoretically possible, but the implementations are further 2191 limited due to memory layouts. 2192 2193 If unsure, say Y. 2194 2195# Relocation on x86 needs some additional build support 2196config X86_NEED_RELOCS 2197 def_bool y 2198 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2199 2200config PHYSICAL_ALIGN 2201 hex "Alignment value to which kernel should be aligned" 2202 default "0x200000" 2203 range 0x2000 0x1000000 if X86_32 2204 range 0x200000 0x1000000 if X86_64 2205 help 2206 This value puts the alignment restrictions on physical address 2207 where kernel is loaded and run from. Kernel is compiled for an 2208 address which meets above alignment restriction. 2209 2210 If bootloader loads the kernel at a non-aligned address and 2211 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2212 address aligned to above value and run from there. 2213 2214 If bootloader loads the kernel at a non-aligned address and 2215 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2216 load address and decompress itself to the address it has been 2217 compiled for and run from there. The address for which kernel is 2218 compiled already meets above alignment restrictions. Hence the 2219 end result is that kernel runs from a physical address meeting 2220 above alignment restrictions. 2221 2222 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2223 this value must be a multiple of 0x200000. 2224 2225 Don't change this unless you know what you are doing. 2226 2227config DYNAMIC_MEMORY_LAYOUT 2228 bool 2229 help 2230 This option makes base addresses of vmalloc and vmemmap as well as 2231 __PAGE_OFFSET movable during boot. 2232 2233config RANDOMIZE_MEMORY 2234 bool "Randomize the kernel memory sections" 2235 depends on X86_64 2236 depends on RANDOMIZE_BASE 2237 select DYNAMIC_MEMORY_LAYOUT 2238 default RANDOMIZE_BASE 2239 help 2240 Randomizes the base virtual address of kernel memory sections 2241 (physical memory mapping, vmalloc & vmemmap). This security feature 2242 makes exploits relying on predictable memory locations less reliable. 2243 2244 The order of allocations remains unchanged. Entropy is generated in 2245 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2246 configuration have in average 30,000 different possible virtual 2247 addresses for each memory section. 2248 2249 If unsure, say Y. 2250 2251config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2252 hex "Physical memory mapping padding" if EXPERT 2253 depends on RANDOMIZE_MEMORY 2254 default "0xa" if MEMORY_HOTPLUG 2255 default "0x0" 2256 range 0x1 0x40 if MEMORY_HOTPLUG 2257 range 0x0 0x40 2258 help 2259 Define the padding in terabytes added to the existing physical 2260 memory size during kernel memory randomization. It is useful 2261 for memory hotplug support but reduces the entropy available for 2262 address randomization. 2263 2264 If unsure, leave at the default value. 2265 2266config ADDRESS_MASKING 2267 bool "Linear Address Masking support" 2268 depends on X86_64 2269 help 2270 Linear Address Masking (LAM) modifies the checking that is applied 2271 to 64-bit linear addresses, allowing software to use of the 2272 untranslated address bits for metadata. 2273 2274 The capability can be used for efficient address sanitizers (ASAN) 2275 implementation and for optimizations in JITs. 2276 2277config HOTPLUG_CPU 2278 def_bool y 2279 depends on SMP 2280 2281config COMPAT_VDSO 2282 def_bool n 2283 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2284 depends on COMPAT_32 2285 help 2286 Certain buggy versions of glibc will crash if they are 2287 presented with a 32-bit vDSO that is not mapped at the address 2288 indicated in its segment table. 2289 2290 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2291 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2292 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2293 the only released version with the bug, but OpenSUSE 9 2294 contains a buggy "glibc 2.3.2". 2295 2296 The symptom of the bug is that everything crashes on startup, saying: 2297 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2298 2299 Saying Y here changes the default value of the vdso32 boot 2300 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2301 This works around the glibc bug but hurts performance. 2302 2303 If unsure, say N: if you are compiling your own kernel, you 2304 are unlikely to be using a buggy version of glibc. 2305 2306choice 2307 prompt "vsyscall table for legacy applications" 2308 depends on X86_64 2309 default LEGACY_VSYSCALL_XONLY 2310 help 2311 Legacy user code that does not know how to find the vDSO expects 2312 to be able to issue three syscalls by calling fixed addresses in 2313 kernel space. Since this location is not randomized with ASLR, 2314 it can be used to assist security vulnerability exploitation. 2315 2316 This setting can be changed at boot time via the kernel command 2317 line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2318 is deprecated and can only be enabled using the kernel command 2319 line. 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_XONLY 2328 bool "Emulate execution only" 2329 help 2330 The kernel traps and emulates calls into the fixed vsyscall 2331 address mapping and does not allow reads. This 2332 configuration is recommended when userspace might use the 2333 legacy vsyscall area but support for legacy binary 2334 instrumentation of legacy code is not needed. It mitigates 2335 certain uses of the vsyscall area as an ASLR-bypassing 2336 buffer. 2337 2338 config LEGACY_VSYSCALL_NONE 2339 bool "None" 2340 help 2341 There will be no vsyscall mapping at all. This will 2342 eliminate any risk of ASLR bypass due to the vsyscall 2343 fixed address mapping. Attempts to use the vsyscalls 2344 will be reported to dmesg, so that either old or 2345 malicious userspace programs can be identified. 2346 2347endchoice 2348 2349config CMDLINE_BOOL 2350 bool "Built-in kernel command line" 2351 help 2352 Allow for specifying boot arguments to the kernel at 2353 build time. On some systems (e.g. embedded ones), it is 2354 necessary or convenient to provide some or all of the 2355 kernel boot arguments with the kernel itself (that is, 2356 to not rely on the boot loader to provide them.) 2357 2358 To compile command line arguments into the kernel, 2359 set this option to 'Y', then fill in the 2360 boot arguments in CONFIG_CMDLINE. 2361 2362 Systems with fully functional boot loaders (i.e. non-embedded) 2363 should leave this option set to 'N'. 2364 2365config CMDLINE 2366 string "Built-in kernel command string" 2367 depends on CMDLINE_BOOL 2368 default "" 2369 help 2370 Enter arguments here that should be compiled into the kernel 2371 image and used at boot time. If the boot loader provides a 2372 command line at boot time, it is appended to this string to 2373 form the full kernel command line, when the system boots. 2374 2375 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2376 change this behavior. 2377 2378 In most cases, the command line (whether built-in or provided 2379 by the boot loader) should specify the device for the root 2380 file system. 2381 2382config CMDLINE_OVERRIDE 2383 bool "Built-in command line overrides boot loader arguments" 2384 depends on CMDLINE_BOOL && CMDLINE != "" 2385 help 2386 Set this option to 'Y' to have the kernel ignore the boot loader 2387 command line, and use ONLY the built-in command line. 2388 2389 This is used to work around broken boot loaders. This should 2390 be set to 'N' under normal conditions. 2391 2392config MODIFY_LDT_SYSCALL 2393 bool "Enable the LDT (local descriptor table)" if EXPERT 2394 default y 2395 help 2396 Linux can allow user programs to install a per-process x86 2397 Local Descriptor Table (LDT) using the modify_ldt(2) system 2398 call. This is required to run 16-bit or segmented code such as 2399 DOSEMU or some Wine programs. It is also used by some very old 2400 threading libraries. 2401 2402 Enabling this feature adds a small amount of overhead to 2403 context switches and increases the low-level kernel attack 2404 surface. Disabling it removes the modify_ldt(2) system call. 2405 2406 Saying 'N' here may make sense for embedded or server kernels. 2407 2408config STRICT_SIGALTSTACK_SIZE 2409 bool "Enforce strict size checking for sigaltstack" 2410 depends on DYNAMIC_SIGFRAME 2411 help 2412 For historical reasons MINSIGSTKSZ is a constant which became 2413 already too small with AVX512 support. Add a mechanism to 2414 enforce strict checking of the sigaltstack size against the 2415 real size of the FPU frame. This option enables the check 2416 by default. It can also be controlled via the kernel command 2417 line option 'strict_sas_size' independent of this config 2418 switch. Enabling it might break existing applications which 2419 allocate a too small sigaltstack but 'work' because they 2420 never get a signal delivered. 2421 2422 Say 'N' unless you want to really enforce this check. 2423 2424config CFI_AUTO_DEFAULT 2425 bool "Attempt to use FineIBT by default at boot time" 2426 depends on FINEIBT 2427 default y 2428 help 2429 Attempt to use FineIBT by default at boot time. If enabled, 2430 this is the same as booting with "cfi=auto". If disabled, 2431 this is the same as booting with "cfi=kcfi". 2432 2433source "kernel/livepatch/Kconfig" 2434 2435endmenu 2436 2437config CC_HAS_NAMED_AS 2438 def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null) 2439 depends on CC_IS_GCC 2440 2441config CC_HAS_NAMED_AS_FIXED_SANITIZERS 2442 def_bool CC_IS_GCC && GCC_VERSION >= 130300 2443 2444config USE_X86_SEG_SUPPORT 2445 def_bool y 2446 depends on CC_HAS_NAMED_AS 2447 # 2448 # -fsanitize=kernel-address (KASAN) and -fsanitize=thread 2449 # (KCSAN) are incompatible with named address spaces with 2450 # GCC < 13.3 - see GCC PR sanitizer/111736. 2451 # 2452 depends on !(KASAN || KCSAN) || CC_HAS_NAMED_AS_FIXED_SANITIZERS 2453 2454config CC_HAS_SLS 2455 def_bool $(cc-option,-mharden-sls=all) 2456 2457config CC_HAS_RETURN_THUNK 2458 def_bool $(cc-option,-mfunction-return=thunk-extern) 2459 2460config CC_HAS_ENTRY_PADDING 2461 def_bool $(cc-option,-fpatchable-function-entry=16,16) 2462 2463config FUNCTION_PADDING_CFI 2464 int 2465 default 59 if FUNCTION_ALIGNMENT_64B 2466 default 27 if FUNCTION_ALIGNMENT_32B 2467 default 11 if FUNCTION_ALIGNMENT_16B 2468 default 3 if FUNCTION_ALIGNMENT_8B 2469 default 0 2470 2471# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG 2472# except Kconfig can't do arithmetic :/ 2473config FUNCTION_PADDING_BYTES 2474 int 2475 default FUNCTION_PADDING_CFI if CFI_CLANG 2476 default FUNCTION_ALIGNMENT 2477 2478config CALL_PADDING 2479 def_bool n 2480 depends on CC_HAS_ENTRY_PADDING && OBJTOOL 2481 select FUNCTION_ALIGNMENT_16B 2482 2483config FINEIBT 2484 def_bool y 2485 depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE 2486 select CALL_PADDING 2487 2488config HAVE_CALL_THUNKS 2489 def_bool y 2490 depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL 2491 2492config CALL_THUNKS 2493 def_bool n 2494 select CALL_PADDING 2495 2496config PREFIX_SYMBOLS 2497 def_bool y 2498 depends on CALL_PADDING && !CFI_CLANG 2499 2500menuconfig CPU_MITIGATIONS 2501 bool "Mitigations for CPU vulnerabilities" 2502 default y 2503 help 2504 Say Y here to enable options which enable mitigations for hardware 2505 vulnerabilities (usually related to speculative execution). 2506 Mitigations can be disabled or restricted to SMT systems at runtime 2507 via the "mitigations" kernel parameter. 2508 2509 If you say N, all mitigations will be disabled. This CANNOT be 2510 overridden at runtime. 2511 2512 Say 'Y', unless you really know what you are doing. 2513 2514if CPU_MITIGATIONS 2515 2516config MITIGATION_PAGE_TABLE_ISOLATION 2517 bool "Remove the kernel mapping in user mode" 2518 default y 2519 depends on (X86_64 || X86_PAE) 2520 help 2521 This feature reduces the number of hardware side channels by 2522 ensuring that the majority of kernel addresses are not mapped 2523 into userspace. 2524 2525 See Documentation/arch/x86/pti.rst for more details. 2526 2527config MITIGATION_RETPOLINE 2528 bool "Avoid speculative indirect branches in kernel" 2529 select OBJTOOL if HAVE_OBJTOOL 2530 default y 2531 help 2532 Compile kernel with the retpoline compiler options to guard against 2533 kernel-to-user data leaks by avoiding speculative indirect 2534 branches. Requires a compiler with -mindirect-branch=thunk-extern 2535 support for full protection. The kernel may run slower. 2536 2537config MITIGATION_RETHUNK 2538 bool "Enable return-thunks" 2539 depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK 2540 select OBJTOOL if HAVE_OBJTOOL 2541 default y if X86_64 2542 help 2543 Compile the kernel with the return-thunks compiler option to guard 2544 against kernel-to-user data leaks by avoiding return speculation. 2545 Requires a compiler with -mfunction-return=thunk-extern 2546 support for full protection. The kernel may run slower. 2547 2548config MITIGATION_UNRET_ENTRY 2549 bool "Enable UNRET on kernel entry" 2550 depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64 2551 default y 2552 help 2553 Compile the kernel with support for the retbleed=unret mitigation. 2554 2555config MITIGATION_CALL_DEPTH_TRACKING 2556 bool "Mitigate RSB underflow with call depth tracking" 2557 depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS 2558 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 2559 select CALL_THUNKS 2560 default y 2561 help 2562 Compile the kernel with call depth tracking to mitigate the Intel 2563 SKL Return-Speculation-Buffer (RSB) underflow issue. The 2564 mitigation is off by default and needs to be enabled on the 2565 kernel command line via the retbleed=stuff option. For 2566 non-affected systems the overhead of this option is marginal as 2567 the call depth tracking is using run-time generated call thunks 2568 in a compiler generated padding area and call patching. This 2569 increases text size by ~5%. For non affected systems this space 2570 is unused. On affected SKL systems this results in a significant 2571 performance gain over the IBRS mitigation. 2572 2573config CALL_THUNKS_DEBUG 2574 bool "Enable call thunks and call depth tracking debugging" 2575 depends on MITIGATION_CALL_DEPTH_TRACKING 2576 select FUNCTION_ALIGNMENT_32B 2577 default n 2578 help 2579 Enable call/ret counters for imbalance detection and build in 2580 a noisy dmesg about callthunks generation and call patching for 2581 trouble shooting. The debug prints need to be enabled on the 2582 kernel command line with 'debug-callthunks'. 2583 Only enable this when you are debugging call thunks as this 2584 creates a noticeable runtime overhead. If unsure say N. 2585 2586config MITIGATION_IBPB_ENTRY 2587 bool "Enable IBPB on kernel entry" 2588 depends on CPU_SUP_AMD && X86_64 2589 default y 2590 help 2591 Compile the kernel with support for the retbleed=ibpb mitigation. 2592 2593config MITIGATION_IBRS_ENTRY 2594 bool "Enable IBRS on kernel entry" 2595 depends on CPU_SUP_INTEL && X86_64 2596 default y 2597 help 2598 Compile the kernel with support for the spectre_v2=ibrs mitigation. 2599 This mitigates both spectre_v2 and retbleed at great cost to 2600 performance. 2601 2602config MITIGATION_SRSO 2603 bool "Mitigate speculative RAS overflow on AMD" 2604 depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK 2605 default y 2606 help 2607 Enable the SRSO mitigation needed on AMD Zen1-4 machines. 2608 2609config MITIGATION_SLS 2610 bool "Mitigate Straight-Line-Speculation" 2611 depends on CC_HAS_SLS && X86_64 2612 select OBJTOOL if HAVE_OBJTOOL 2613 default n 2614 help 2615 Compile the kernel with straight-line-speculation options to guard 2616 against straight line speculation. The kernel image might be slightly 2617 larger. 2618 2619config MITIGATION_GDS 2620 bool "Mitigate Gather Data Sampling" 2621 depends on CPU_SUP_INTEL 2622 default y 2623 help 2624 Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware 2625 vulnerability which allows unprivileged speculative access to data 2626 which was previously stored in vector registers. The attacker uses gather 2627 instructions to infer the stale vector register data. 2628 2629config MITIGATION_RFDS 2630 bool "RFDS Mitigation" 2631 depends on CPU_SUP_INTEL 2632 default y 2633 help 2634 Enable mitigation for Register File Data Sampling (RFDS) by default. 2635 RFDS is a hardware vulnerability which affects Intel Atom CPUs. It 2636 allows unprivileged speculative access to stale data previously 2637 stored in floating point, vector and integer registers. 2638 See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst> 2639 2640config MITIGATION_SPECTRE_BHI 2641 bool "Mitigate Spectre-BHB (Branch History Injection)" 2642 depends on CPU_SUP_INTEL 2643 default y 2644 help 2645 Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks 2646 where the branch history buffer is poisoned to speculatively steer 2647 indirect branches. 2648 See <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2649 2650config MITIGATION_MDS 2651 bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug" 2652 depends on CPU_SUP_INTEL 2653 default y 2654 help 2655 Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is 2656 a hardware vulnerability which allows unprivileged speculative access 2657 to data which is available in various CPU internal buffers. 2658 See also <file:Documentation/admin-guide/hw-vuln/mds.rst> 2659 2660config MITIGATION_TAA 2661 bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug" 2662 depends on CPU_SUP_INTEL 2663 default y 2664 help 2665 Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware 2666 vulnerability that allows unprivileged speculative access to data 2667 which is available in various CPU internal buffers by using 2668 asynchronous aborts within an Intel TSX transactional region. 2669 See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst> 2670 2671config MITIGATION_MMIO_STALE_DATA 2672 bool "Mitigate MMIO Stale Data hardware bug" 2673 depends on CPU_SUP_INTEL 2674 default y 2675 help 2676 Enable mitigation for MMIO Stale Data hardware bugs. Processor MMIO 2677 Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO) 2678 vulnerabilities that can expose data. The vulnerabilities require the 2679 attacker to have access to MMIO. 2680 See also 2681 <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst> 2682 2683config MITIGATION_L1TF 2684 bool "Mitigate L1 Terminal Fault (L1TF) hardware bug" 2685 depends on CPU_SUP_INTEL 2686 default y 2687 help 2688 Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a 2689 hardware vulnerability which allows unprivileged speculative access to data 2690 available in the Level 1 Data Cache. 2691 See <file:Documentation/admin-guide/hw-vuln/l1tf.rst 2692 2693config MITIGATION_RETBLEED 2694 bool "Mitigate RETBleed hardware bug" 2695 depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY 2696 default y 2697 help 2698 Enable mitigation for RETBleed (Arbitrary Speculative Code Execution 2699 with Return Instructions) vulnerability. RETBleed is a speculative 2700 execution attack which takes advantage of microarchitectural behavior 2701 in many modern microprocessors, similar to Spectre v2. An 2702 unprivileged attacker can use these flaws to bypass conventional 2703 memory security restrictions to gain read access to privileged memory 2704 that would otherwise be inaccessible. 2705 2706config MITIGATION_SPECTRE_V1 2707 bool "Mitigate SPECTRE V1 hardware bug" 2708 default y 2709 help 2710 Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a 2711 class of side channel attacks that takes advantage of speculative 2712 execution that bypasses conditional branch instructions used for 2713 memory access bounds check. 2714 See also <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2715 2716config MITIGATION_SPECTRE_V2 2717 bool "Mitigate SPECTRE V2 hardware bug" 2718 default y 2719 help 2720 Enable mitigation for Spectre V2 (Branch Target Injection). Spectre 2721 V2 is a class of side channel attacks that takes advantage of 2722 indirect branch predictors inside the processor. In Spectre variant 2 2723 attacks, the attacker can steer speculative indirect branches in the 2724 victim to gadget code by poisoning the branch target buffer of a CPU 2725 used for predicting indirect branch addresses. 2726 See also <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2727 2728config MITIGATION_SRBDS 2729 bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug" 2730 depends on CPU_SUP_INTEL 2731 default y 2732 help 2733 Enable mitigation for Special Register Buffer Data Sampling (SRBDS). 2734 SRBDS is a hardware vulnerability that allows Microarchitectural Data 2735 Sampling (MDS) techniques to infer values returned from special 2736 register accesses. An unprivileged user can extract values returned 2737 from RDRAND and RDSEED executed on another core or sibling thread 2738 using MDS techniques. 2739 See also 2740 <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst> 2741 2742config MITIGATION_SSB 2743 bool "Mitigate Speculative Store Bypass (SSB) hardware bug" 2744 default y 2745 help 2746 Enable mitigation for Speculative Store Bypass (SSB). SSB is a 2747 hardware security vulnerability and its exploitation takes advantage 2748 of speculative execution in a similar way to the Meltdown and Spectre 2749 security vulnerabilities. 2750 2751endif 2752 2753config ARCH_HAS_ADD_PAGES 2754 def_bool y 2755 depends on ARCH_ENABLE_MEMORY_HOTPLUG 2756 2757menu "Power management and ACPI options" 2758 2759config ARCH_HIBERNATION_HEADER 2760 def_bool y 2761 depends on HIBERNATION 2762 2763source "kernel/power/Kconfig" 2764 2765source "drivers/acpi/Kconfig" 2766 2767config X86_APM_BOOT 2768 def_bool y 2769 depends on APM 2770 2771menuconfig APM 2772 tristate "APM (Advanced Power Management) BIOS support" 2773 depends on X86_32 && PM_SLEEP 2774 help 2775 APM is a BIOS specification for saving power using several different 2776 techniques. This is mostly useful for battery powered laptops with 2777 APM compliant BIOSes. If you say Y here, the system time will be 2778 reset after a RESUME operation, the /proc/apm device will provide 2779 battery status information, and user-space programs will receive 2780 notification of APM "events" (e.g. battery status change). 2781 2782 If you select "Y" here, you can disable actual use of the APM 2783 BIOS by passing the "apm=off" option to the kernel at boot time. 2784 2785 Note that the APM support is almost completely disabled for 2786 machines with more than one CPU. 2787 2788 In order to use APM, you will need supporting software. For location 2789 and more information, read <file:Documentation/power/apm-acpi.rst> 2790 and the Battery Powered Linux mini-HOWTO, available from 2791 <http://www.tldp.org/docs.html#howto>. 2792 2793 This driver does not spin down disk drives (see the hdparm(8) 2794 manpage ("man 8 hdparm") for that), and it doesn't turn off 2795 VESA-compliant "green" monitors. 2796 2797 This driver does not support the TI 4000M TravelMate and the ACER 2798 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2799 desktop machines also don't have compliant BIOSes, and this driver 2800 may cause those machines to panic during the boot phase. 2801 2802 Generally, if you don't have a battery in your machine, there isn't 2803 much point in using this driver and you should say N. If you get 2804 random kernel OOPSes or reboots that don't seem to be related to 2805 anything, try disabling/enabling this option (or disabling/enabling 2806 APM in your BIOS). 2807 2808 Some other things you should try when experiencing seemingly random, 2809 "weird" problems: 2810 2811 1) make sure that you have enough swap space and that it is 2812 enabled. 2813 2) pass the "idle=poll" option to the kernel 2814 3) switch on floating point emulation in the kernel and pass 2815 the "no387" option to the kernel 2816 4) pass the "floppy=nodma" option to the kernel 2817 5) pass the "mem=4M" option to the kernel (thereby disabling 2818 all but the first 4 MB of RAM) 2819 6) make sure that the CPU is not over clocked. 2820 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2821 8) disable the cache from your BIOS settings 2822 9) install a fan for the video card or exchange video RAM 2823 10) install a better fan for the CPU 2824 11) exchange RAM chips 2825 12) exchange the motherboard. 2826 2827 To compile this driver as a module, choose M here: the 2828 module will be called apm. 2829 2830if APM 2831 2832config APM_IGNORE_USER_SUSPEND 2833 bool "Ignore USER SUSPEND" 2834 help 2835 This option will ignore USER SUSPEND requests. On machines with a 2836 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2837 series notebooks, it is necessary to say Y because of a BIOS bug. 2838 2839config APM_DO_ENABLE 2840 bool "Enable PM at boot time" 2841 help 2842 Enable APM features at boot time. From page 36 of the APM BIOS 2843 specification: "When disabled, the APM BIOS does not automatically 2844 power manage devices, enter the Standby State, enter the Suspend 2845 State, or take power saving steps in response to CPU Idle calls." 2846 This driver will make CPU Idle calls when Linux is idle (unless this 2847 feature is turned off -- see "Do CPU IDLE calls", below). This 2848 should always save battery power, but more complicated APM features 2849 will be dependent on your BIOS implementation. You may need to turn 2850 this option off if your computer hangs at boot time when using APM 2851 support, or if it beeps continuously instead of suspending. Turn 2852 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2853 T400CDT. This is off by default since most machines do fine without 2854 this feature. 2855 2856config APM_CPU_IDLE 2857 depends on CPU_IDLE 2858 bool "Make CPU Idle calls when idle" 2859 help 2860 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2861 On some machines, this can activate improved power savings, such as 2862 a slowed CPU clock rate, when the machine is idle. These idle calls 2863 are made after the idle loop has run for some length of time (e.g., 2864 333 mS). On some machines, this will cause a hang at boot time or 2865 whenever the CPU becomes idle. (On machines with more than one CPU, 2866 this option does nothing.) 2867 2868config APM_DISPLAY_BLANK 2869 bool "Enable console blanking using APM" 2870 help 2871 Enable console blanking using the APM. Some laptops can use this to 2872 turn off the LCD backlight when the screen blanker of the Linux 2873 virtual console blanks the screen. Note that this is only used by 2874 the virtual console screen blanker, and won't turn off the backlight 2875 when using the X Window system. This also doesn't have anything to 2876 do with your VESA-compliant power-saving monitor. Further, this 2877 option doesn't work for all laptops -- it might not turn off your 2878 backlight at all, or it might print a lot of errors to the console, 2879 especially if you are using gpm. 2880 2881config APM_ALLOW_INTS 2882 bool "Allow interrupts during APM BIOS calls" 2883 help 2884 Normally we disable external interrupts while we are making calls to 2885 the APM BIOS as a measure to lessen the effects of a badly behaving 2886 BIOS implementation. The BIOS should reenable interrupts if it 2887 needs to. Unfortunately, some BIOSes do not -- especially those in 2888 many of the newer IBM Thinkpads. If you experience hangs when you 2889 suspend, try setting this to Y. Otherwise, say N. 2890 2891endif # APM 2892 2893source "drivers/cpufreq/Kconfig" 2894 2895source "drivers/cpuidle/Kconfig" 2896 2897source "drivers/idle/Kconfig" 2898 2899endmenu 2900 2901menu "Bus options (PCI etc.)" 2902 2903choice 2904 prompt "PCI access mode" 2905 depends on X86_32 && PCI 2906 default PCI_GOANY 2907 help 2908 On PCI systems, the BIOS can be used to detect the PCI devices and 2909 determine their configuration. However, some old PCI motherboards 2910 have BIOS bugs and may crash if this is done. Also, some embedded 2911 PCI-based systems don't have any BIOS at all. Linux can also try to 2912 detect the PCI hardware directly without using the BIOS. 2913 2914 With this option, you can specify how Linux should detect the 2915 PCI devices. If you choose "BIOS", the BIOS will be used, 2916 if you choose "Direct", the BIOS won't be used, and if you 2917 choose "MMConfig", then PCI Express MMCONFIG will be used. 2918 If you choose "Any", the kernel will try MMCONFIG, then the 2919 direct access method and falls back to the BIOS if that doesn't 2920 work. If unsure, go with the default, which is "Any". 2921 2922config PCI_GOBIOS 2923 bool "BIOS" 2924 2925config PCI_GOMMCONFIG 2926 bool "MMConfig" 2927 2928config PCI_GODIRECT 2929 bool "Direct" 2930 2931config PCI_GOOLPC 2932 bool "OLPC XO-1" 2933 depends on OLPC 2934 2935config PCI_GOANY 2936 bool "Any" 2937 2938endchoice 2939 2940config PCI_BIOS 2941 def_bool y 2942 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2943 2944# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2945config PCI_DIRECT 2946 def_bool y 2947 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2948 2949config PCI_MMCONFIG 2950 bool "Support mmconfig PCI config space access" if X86_64 2951 default y 2952 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2953 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2954 2955config PCI_OLPC 2956 def_bool y 2957 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2958 2959config PCI_XEN 2960 def_bool y 2961 depends on PCI && XEN 2962 2963config MMCONF_FAM10H 2964 def_bool y 2965 depends on X86_64 && PCI_MMCONFIG && ACPI 2966 2967config PCI_CNB20LE_QUIRK 2968 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2969 depends on PCI 2970 help 2971 Read the PCI windows out of the CNB20LE host bridge. This allows 2972 PCI hotplug to work on systems with the CNB20LE chipset which do 2973 not have ACPI. 2974 2975 There's no public spec for this chipset, and this functionality 2976 is known to be incomplete. 2977 2978 You should say N unless you know you need this. 2979 2980config ISA_BUS 2981 bool "ISA bus support on modern systems" if EXPERT 2982 help 2983 Expose ISA bus device drivers and options available for selection and 2984 configuration. Enable this option if your target machine has an ISA 2985 bus. ISA is an older system, displaced by PCI and newer bus 2986 architectures -- if your target machine is modern, it probably does 2987 not have an ISA bus. 2988 2989 If unsure, say N. 2990 2991# x86_64 have no ISA slots, but can have ISA-style DMA. 2992config ISA_DMA_API 2993 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2994 default y 2995 help 2996 Enables ISA-style DMA support for devices requiring such controllers. 2997 If unsure, say Y. 2998 2999if X86_32 3000 3001config ISA 3002 bool "ISA support" 3003 help 3004 Find out whether you have ISA slots on your motherboard. ISA is the 3005 name of a bus system, i.e. the way the CPU talks to the other stuff 3006 inside your box. Other bus systems are PCI, EISA, MicroChannel 3007 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 3008 newer boards don't support it. If you have ISA, say Y, otherwise N. 3009 3010config SCx200 3011 tristate "NatSemi SCx200 support" 3012 help 3013 This provides basic support for National Semiconductor's 3014 (now AMD's) Geode processors. The driver probes for the 3015 PCI-IDs of several on-chip devices, so its a good dependency 3016 for other scx200_* drivers. 3017 3018 If compiled as a module, the driver is named scx200. 3019 3020config SCx200HR_TIMER 3021 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 3022 depends on SCx200 3023 default y 3024 help 3025 This driver provides a clocksource built upon the on-chip 3026 27MHz high-resolution timer. Its also a workaround for 3027 NSC Geode SC-1100's buggy TSC, which loses time when the 3028 processor goes idle (as is done by the scheduler). The 3029 other workaround is idle=poll boot option. 3030 3031config OLPC 3032 bool "One Laptop Per Child support" 3033 depends on !X86_PAE 3034 select GPIOLIB 3035 select OF 3036 select OF_PROMTREE 3037 select IRQ_DOMAIN 3038 select OLPC_EC 3039 help 3040 Add support for detecting the unique features of the OLPC 3041 XO hardware. 3042 3043config OLPC_XO1_PM 3044 bool "OLPC XO-1 Power Management" 3045 depends on OLPC && MFD_CS5535=y && PM_SLEEP 3046 help 3047 Add support for poweroff and suspend of the OLPC XO-1 laptop. 3048 3049config OLPC_XO1_RTC 3050 bool "OLPC XO-1 Real Time Clock" 3051 depends on OLPC_XO1_PM && RTC_DRV_CMOS 3052 help 3053 Add support for the XO-1 real time clock, which can be used as a 3054 programmable wakeup source. 3055 3056config OLPC_XO1_SCI 3057 bool "OLPC XO-1 SCI extras" 3058 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 3059 depends on INPUT=y 3060 select POWER_SUPPLY 3061 help 3062 Add support for SCI-based features of the OLPC XO-1 laptop: 3063 - EC-driven system wakeups 3064 - Power button 3065 - Ebook switch 3066 - Lid switch 3067 - AC adapter status updates 3068 - Battery status updates 3069 3070config OLPC_XO15_SCI 3071 bool "OLPC XO-1.5 SCI extras" 3072 depends on OLPC && ACPI 3073 select POWER_SUPPLY 3074 help 3075 Add support for SCI-based features of the OLPC XO-1.5 laptop: 3076 - EC-driven system wakeups 3077 - AC adapter status updates 3078 - Battery status updates 3079 3080config GEODE_COMMON 3081 bool 3082 3083config ALIX 3084 bool "PCEngines ALIX System Support (LED setup)" 3085 select GPIOLIB 3086 select GEODE_COMMON 3087 help 3088 This option enables system support for the PCEngines ALIX. 3089 At present this just sets up LEDs for GPIO control on 3090 ALIX2/3/6 boards. However, other system specific setup should 3091 get added here. 3092 3093 Note: You must still enable the drivers for GPIO and LED support 3094 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 3095 3096 Note: You have to set alix.force=1 for boards with Award BIOS. 3097 3098config NET5501 3099 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 3100 select GPIOLIB 3101 select GEODE_COMMON 3102 help 3103 This option enables system support for the Soekris Engineering net5501. 3104 3105config GEOS 3106 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 3107 select GPIOLIB 3108 select GEODE_COMMON 3109 depends on DMI 3110 help 3111 This option enables system support for the Traverse Technologies GEOS. 3112 3113config TS5500 3114 bool "Technologic Systems TS-5500 platform support" 3115 depends on MELAN 3116 select CHECK_SIGNATURE 3117 select NEW_LEDS 3118 select LEDS_CLASS 3119 help 3120 This option enables system support for the Technologic Systems TS-5500. 3121 3122endif # X86_32 3123 3124config AMD_NB 3125 def_bool y 3126 depends on CPU_SUP_AMD && PCI 3127 3128endmenu 3129 3130menu "Binary Emulations" 3131 3132config IA32_EMULATION 3133 bool "IA32 Emulation" 3134 depends on X86_64 3135 select ARCH_WANT_OLD_COMPAT_IPC 3136 select BINFMT_ELF 3137 select COMPAT_OLD_SIGACTION 3138 help 3139 Include code to run legacy 32-bit programs under a 3140 64-bit kernel. You should likely turn this on, unless you're 3141 100% sure that you don't have any 32-bit programs left. 3142 3143config IA32_EMULATION_DEFAULT_DISABLED 3144 bool "IA32 emulation disabled by default" 3145 default n 3146 depends on IA32_EMULATION 3147 help 3148 Make IA32 emulation disabled by default. This prevents loading 32-bit 3149 processes and access to 32-bit syscalls. If unsure, leave it to its 3150 default value. 3151 3152config X86_X32_ABI 3153 bool "x32 ABI for 64-bit mode" 3154 depends on X86_64 3155 # llvm-objcopy does not convert x86_64 .note.gnu.property or 3156 # compressed debug sections to x86_x32 properly: 3157 # https://github.com/ClangBuiltLinux/linux/issues/514 3158 # https://github.com/ClangBuiltLinux/linux/issues/1141 3159 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 3160 help 3161 Include code to run binaries for the x32 native 32-bit ABI 3162 for 64-bit processors. An x32 process gets access to the 3163 full 64-bit register file and wide data path while leaving 3164 pointers at 32 bits for smaller memory footprint. 3165 3166config COMPAT_32 3167 def_bool y 3168 depends on IA32_EMULATION || X86_32 3169 select HAVE_UID16 3170 select OLD_SIGSUSPEND3 3171 3172config COMPAT 3173 def_bool y 3174 depends on IA32_EMULATION || X86_X32_ABI 3175 3176config COMPAT_FOR_U64_ALIGNMENT 3177 def_bool y 3178 depends on COMPAT 3179 3180endmenu 3181 3182config HAVE_ATOMIC_IOMAP 3183 def_bool y 3184 depends on X86_32 3185 3186source "arch/x86/kvm/Kconfig" 3187 3188source "arch/x86/Kconfig.assembler" 3189