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 HAVE_DEBUG_STACKOVERFLOW 18 select KMAP_LOCAL 19 select MODULES_USE_ELF_REL 20 select OLD_SIGACTION 21 select ARCH_SPLIT_ARG64 22 23config X86_64 24 def_bool y 25 depends on 64BIT 26 # Options that are inherently 64-bit kernel only: 27 select ARCH_HAS_GIGANTIC_PAGE 28 select ARCH_HAS_PTDUMP 29 select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 30 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 31 select ARCH_SUPPORTS_PER_VMA_LOCK 32 select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE 33 select HAVE_ARCH_SOFT_DIRTY 34 select MODULES_USE_ELF_RELA 35 select NEED_DMA_MAP_STATE 36 select SWIOTLB 37 select ARCH_HAS_ELFCORE_COMPAT 38 select ZONE_DMA32 39 select EXECMEM if DYNAMIC_FTRACE 40 select ACPI_MRRM if ACPI 41 42config FORCE_DYNAMIC_FTRACE 43 def_bool y 44 depends on X86_32 45 depends on FUNCTION_TRACER 46 select DYNAMIC_FTRACE 47 help 48 We keep the static function tracing (!DYNAMIC_FTRACE) around 49 in order to test the non static function tracing in the 50 generic code, as other architectures still use it. But we 51 only need to keep it around for x86_64. No need to keep it 52 for x86_32. For x86_32, force DYNAMIC_FTRACE. 53# 54# Arch settings 55# 56# ( Note that options that are marked 'if X86_64' could in principle be 57# ported to 32-bit as well. ) 58# 59config X86 60 def_bool y 61 # 62 # Note: keep this list sorted alphabetically 63 # 64 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 65 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 66 select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU 67 select ARCH_32BIT_OFF_T if X86_32 68 select ARCH_CLOCKSOURCE_INIT 69 select ARCH_CONFIGURES_CPU_MITIGATIONS 70 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 71 select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION 72 select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 73 select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG 74 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 75 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 76 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 77 select ARCH_HAS_CPU_ATTACK_VECTORS if CPU_MITIGATIONS 78 select ARCH_HAS_CACHE_LINE_SIZE 79 select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION 80 select ARCH_HAS_CPU_FINALIZE_INIT 81 select ARCH_HAS_CPU_PASID if IOMMU_SVA 82 select ARCH_HAS_CURRENT_STACK_POINTER 83 select ARCH_HAS_DEBUG_VIRTUAL 84 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 85 select ARCH_HAS_DEVMEM_IS_ALLOWED 86 select ARCH_HAS_DMA_OPS if GART_IOMMU || XEN 87 select ARCH_HAS_EARLY_DEBUG if KGDB 88 select ARCH_HAS_ELF_RANDOMIZE 89 select ARCH_HAS_EXECMEM_ROX if X86_64 && STRICT_MODULE_RWX 90 select ARCH_HAS_FAST_MULTIPLIER 91 select ARCH_HAS_FORTIFY_SOURCE 92 select ARCH_HAS_GCOV_PROFILE_ALL 93 select ARCH_HAS_KCOV if X86_64 94 select ARCH_HAS_KERNEL_FPU_SUPPORT 95 select ARCH_HAS_MEM_ENCRYPT 96 select ARCH_HAS_MEMBARRIER_SYNC_CORE 97 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 98 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 99 select ARCH_HAS_PMEM_API if X86_64 100 select ARCH_HAS_PREEMPT_LAZY 101 select ARCH_HAS_PTE_SPECIAL 102 select ARCH_HAS_HW_PTE_YOUNG 103 select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 104 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 105 select ARCH_HAS_COPY_MC if X86_64 106 select ARCH_HAS_SET_MEMORY 107 select ARCH_HAS_SET_DIRECT_MAP 108 select ARCH_HAS_STRICT_KERNEL_RWX 109 select ARCH_HAS_STRICT_MODULE_RWX 110 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 111 select ARCH_HAS_SYSCALL_WRAPPER 112 select ARCH_HAS_UBSAN 113 select ARCH_HAS_DEBUG_WX 114 select ARCH_HAS_ZONE_DMA_SET if EXPERT 115 select ARCH_HAVE_NMI_SAFE_CMPXCHG 116 select ARCH_HAVE_EXTRA_ELF_NOTES 117 select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 118 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 119 select ARCH_MIGHT_HAVE_PC_PARPORT 120 select ARCH_MIGHT_HAVE_PC_SERIO 121 select ARCH_STACKWALK 122 select ARCH_SUPPORTS_ACPI 123 select ARCH_SUPPORTS_ATOMIC_RMW 124 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 125 select ARCH_SUPPORTS_HUGETLBFS 126 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 127 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 128 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 129 select ARCH_SUPPORTS_CFI_CLANG if X86_64 130 select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG 131 select ARCH_SUPPORTS_LTO_CLANG 132 select ARCH_SUPPORTS_LTO_CLANG_THIN 133 select ARCH_SUPPORTS_RT 134 select ARCH_SUPPORTS_AUTOFDO_CLANG 135 select ARCH_SUPPORTS_PROPELLER_CLANG if X86_64 136 select ARCH_USE_BUILTIN_BSWAP 137 select ARCH_USE_CMPXCHG_LOCKREF if X86_CX8 138 select ARCH_USE_MEMTEST 139 select ARCH_USE_QUEUED_RWLOCKS 140 select ARCH_USE_QUEUED_SPINLOCKS 141 select ARCH_USE_SYM_ANNOTATIONS 142 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 143 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 144 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 145 select ARCH_WANTS_NO_INSTR 146 select ARCH_WANT_GENERAL_HUGETLB 147 select ARCH_WANT_HUGE_PMD_SHARE if X86_64 148 select ARCH_WANT_LD_ORPHAN_WARN 149 select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP if X86_64 150 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP if X86_64 151 select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64 152 select ARCH_WANTS_THP_SWAP if X86_64 153 select ARCH_HAS_PARANOID_L1D_FLUSH 154 select ARCH_WANT_IRQS_OFF_ACTIVATE_MM 155 select BUILDTIME_TABLE_SORT 156 select CLKEVT_I8253 157 select CLOCKSOURCE_WATCHDOG 158 # Word-size accesses may read uninitialized data past the trailing \0 159 # in strings and cause false KMSAN reports. 160 select DCACHE_WORD_ACCESS if !KMSAN 161 select DYNAMIC_SIGFRAME 162 select EDAC_ATOMIC_SCRUB 163 select EDAC_SUPPORT 164 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 165 select GENERIC_CLOCKEVENTS_BROADCAST_IDLE if GENERIC_CLOCKEVENTS_BROADCAST 166 select GENERIC_CLOCKEVENTS_MIN_ADJUST 167 select GENERIC_CMOS_UPDATE 168 select GENERIC_CPU_AUTOPROBE 169 select GENERIC_CPU_DEVICES 170 select GENERIC_CPU_VULNERABILITIES 171 select GENERIC_EARLY_IOREMAP 172 select GENERIC_ENTRY 173 select GENERIC_IOMAP 174 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 175 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 176 select GENERIC_IRQ_MIGRATION if SMP 177 select GENERIC_IRQ_PROBE 178 select GENERIC_IRQ_RESERVATION_MODE 179 select GENERIC_IRQ_SHOW 180 select GENERIC_PENDING_IRQ if SMP 181 select GENERIC_SMP_IDLE_THREAD 182 select GENERIC_TIME_VSYSCALL 183 select GENERIC_GETTIMEOFDAY 184 select GENERIC_VDSO_OVERFLOW_PROTECT 185 select GUP_GET_PXX_LOW_HIGH if X86_PAE 186 select HARDIRQS_SW_RESEND 187 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 188 select HAS_IOPORT 189 select HAVE_ACPI_APEI if ACPI 190 select HAVE_ACPI_APEI_NMI if ACPI 191 select HAVE_ALIGNED_STRUCT_PAGE 192 select HAVE_ARCH_AUDITSYSCALL 193 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 194 select HAVE_ARCH_HUGE_VMALLOC if X86_64 195 select HAVE_ARCH_JUMP_LABEL 196 select HAVE_ARCH_JUMP_LABEL_RELATIVE 197 select HAVE_ARCH_KASAN if X86_64 198 select HAVE_ARCH_KASAN_VMALLOC if X86_64 199 select HAVE_ARCH_KFENCE 200 select HAVE_ARCH_KMSAN if X86_64 201 select HAVE_ARCH_KGDB 202 select HAVE_ARCH_KSTACK_ERASE 203 select HAVE_ARCH_MMAP_RND_BITS if MMU 204 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 205 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 206 select HAVE_ARCH_PREL32_RELOCATIONS 207 select HAVE_ARCH_SECCOMP_FILTER 208 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 209 select HAVE_ARCH_TRACEHOOK 210 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 211 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 212 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 213 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 214 select HAVE_ARCH_VMAP_STACK if X86_64 215 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 216 select HAVE_ARCH_WITHIN_STACK_FRAMES 217 select HAVE_ASM_MODVERSIONS 218 select HAVE_CMPXCHG_DOUBLE 219 select HAVE_CMPXCHG_LOCAL 220 select HAVE_CONTEXT_TRACKING_USER if X86_64 221 select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER 222 select HAVE_C_RECORDMCOUNT 223 select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 224 select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT 225 select HAVE_BUILDTIME_MCOUNT_SORT 226 select HAVE_DEBUG_KMEMLEAK 227 select HAVE_DMA_CONTIGUOUS 228 select HAVE_DYNAMIC_FTRACE 229 select HAVE_DYNAMIC_FTRACE_WITH_REGS 230 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 231 select HAVE_FTRACE_REGS_HAVING_PT_REGS if X86_64 232 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 233 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 234 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 235 select HAVE_EBPF_JIT 236 select HAVE_EFFICIENT_UNALIGNED_ACCESS 237 select HAVE_EISA if X86_32 238 select HAVE_EXIT_THREAD 239 select HAVE_GUP_FAST 240 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 241 select HAVE_FTRACE_GRAPH_FUNC if HAVE_FUNCTION_GRAPH_TRACER 242 select HAVE_FUNCTION_GRAPH_FREGS if HAVE_FUNCTION_GRAPH_TRACER 243 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 244 select HAVE_FUNCTION_TRACER 245 select HAVE_GCC_PLUGINS 246 select HAVE_HW_BREAKPOINT 247 select HAVE_IOREMAP_PROT 248 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 249 select HAVE_IRQ_TIME_ACCOUNTING 250 select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 251 select HAVE_KERNEL_BZIP2 252 select HAVE_KERNEL_GZIP 253 select HAVE_KERNEL_LZ4 254 select HAVE_KERNEL_LZMA 255 select HAVE_KERNEL_LZO 256 select HAVE_KERNEL_XZ 257 select HAVE_KERNEL_ZSTD 258 select HAVE_KPROBES 259 select HAVE_KPROBES_ON_FTRACE 260 select HAVE_FUNCTION_ERROR_INJECTION 261 select HAVE_KRETPROBES 262 select HAVE_RETHOOK 263 select HAVE_LIVEPATCH if X86_64 264 select HAVE_MIXED_BREAKPOINTS_REGS 265 select HAVE_MOD_ARCH_SPECIFIC 266 select HAVE_MOVE_PMD 267 select HAVE_MOVE_PUD 268 select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 269 select HAVE_NMI 270 select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 271 select HAVE_OBJTOOL if X86_64 272 select HAVE_OPTPROBES 273 select HAVE_PAGE_SIZE_4KB 274 select HAVE_PCSPKR_PLATFORM 275 select HAVE_PERF_EVENTS 276 select HAVE_PERF_EVENTS_NMI 277 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 278 select HAVE_PCI 279 select HAVE_PERF_REGS 280 select HAVE_PERF_USER_STACK_DUMP 281 select MMU_GATHER_RCU_TABLE_FREE 282 select MMU_GATHER_MERGE_VMAS 283 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 284 select HAVE_REGS_AND_STACK_ACCESS_API 285 select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 286 select HAVE_FUNCTION_ARG_ACCESS_API 287 select HAVE_SETUP_PER_CPU_AREA 288 select HAVE_SOFTIRQ_ON_OWN_STACK 289 select HAVE_STACKPROTECTOR 290 select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 291 select HAVE_STATIC_CALL 292 select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 293 select HAVE_PREEMPT_DYNAMIC_CALL 294 select HAVE_RSEQ 295 select HAVE_RUST if X86_64 296 select HAVE_SYSCALL_TRACEPOINTS 297 select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 298 select HAVE_UNSTABLE_SCHED_CLOCK 299 select HAVE_USER_RETURN_NOTIFIER 300 select HAVE_GENERIC_VDSO 301 select VDSO_GETRANDOM if X86_64 302 select HOTPLUG_PARALLEL if SMP && X86_64 303 select HOTPLUG_SMT if SMP 304 select HOTPLUG_SPLIT_STARTUP if SMP && X86_32 305 select IRQ_FORCED_THREADING 306 select LOCK_MM_AND_FIND_VMA 307 select NEED_PER_CPU_EMBED_FIRST_CHUNK 308 select NEED_PER_CPU_PAGE_FIRST_CHUNK 309 select NEED_SG_DMA_LENGTH 310 select NUMA_MEMBLKS if NUMA 311 select PCI_DOMAINS if PCI 312 select PCI_LOCKLESS_CONFIG if PCI 313 select PERF_EVENTS 314 select RTC_LIB 315 select RTC_MC146818_LIB 316 select SPARSE_IRQ 317 select SYSCTL_EXCEPTION_TRACE 318 select THREAD_INFO_IN_TASK 319 select TRACE_IRQFLAGS_SUPPORT 320 select TRACE_IRQFLAGS_NMI_SUPPORT 321 select USER_STACKTRACE_SUPPORT 322 select HAVE_ARCH_KCSAN if X86_64 323 select PROC_PID_ARCH_STATUS if PROC_FS 324 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 325 select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 326 select FUNCTION_ALIGNMENT_4B 327 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 328 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 329 select ARCH_SUPPORTS_PT_RECLAIM if X86_64 330 331config INSTRUCTION_DECODER 332 def_bool y 333 depends on KPROBES || PERF_EVENTS || UPROBES 334 335config OUTPUT_FORMAT 336 string 337 default "elf32-i386" if X86_32 338 default "elf64-x86-64" if X86_64 339 340config LOCKDEP_SUPPORT 341 def_bool y 342 343config STACKTRACE_SUPPORT 344 def_bool y 345 346config MMU 347 def_bool y 348 349config ARCH_MMAP_RND_BITS_MIN 350 default 28 if 64BIT 351 default 8 352 353config ARCH_MMAP_RND_BITS_MAX 354 default 32 if 64BIT 355 default 16 356 357config ARCH_MMAP_RND_COMPAT_BITS_MIN 358 default 8 359 360config ARCH_MMAP_RND_COMPAT_BITS_MAX 361 default 16 362 363config SBUS 364 bool 365 366config GENERIC_ISA_DMA 367 def_bool y 368 depends on ISA_DMA_API 369 370config GENERIC_CSUM 371 bool 372 default y if KMSAN || KASAN 373 374config GENERIC_BUG 375 def_bool y 376 depends on BUG 377 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 378 379config GENERIC_BUG_RELATIVE_POINTERS 380 bool 381 382config ARCH_MAY_HAVE_PC_FDC 383 def_bool y 384 depends on ISA_DMA_API 385 386config GENERIC_CALIBRATE_DELAY 387 def_bool y 388 389config ARCH_HAS_CPU_RELAX 390 def_bool y 391 392config ARCH_HIBERNATION_POSSIBLE 393 def_bool y 394 395config ARCH_SUSPEND_POSSIBLE 396 def_bool y 397 398config AUDIT_ARCH 399 def_bool y if X86_64 400 401config KASAN_SHADOW_OFFSET 402 hex 403 depends on KASAN 404 default 0xdffffc0000000000 405 406config HAVE_INTEL_TXT 407 def_bool y 408 depends on INTEL_IOMMU && ACPI 409 410config X86_64_SMP 411 def_bool y 412 depends on X86_64 && SMP 413 414config ARCH_SUPPORTS_UPROBES 415 def_bool y 416 417config FIX_EARLYCON_MEM 418 def_bool y 419 420config DYNAMIC_PHYSICAL_MASK 421 bool 422 423config PGTABLE_LEVELS 424 int 425 default 5 if X86_64 426 default 3 if X86_PAE 427 default 2 428 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 "x2APIC interrupt controller architecture support" 461 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 462 default y 463 help 464 x2APIC is an interrupt controller architecture, a component of which 465 (the local APIC) is present in the CPU. It allows faster access to 466 the local APIC and supports a larger number of CPUs in the system 467 than the predecessors. 468 469 x2APIC was introduced in Intel CPUs around 2008 and in AMD EPYC CPUs 470 in 2019, but it can be disabled by the BIOS. It is also frequently 471 emulated in virtual machines, even when the host CPU does not support 472 it. Support in the CPU can be checked by executing 473 grep x2apic /proc/cpuinfo 474 475 If this configuration option is disabled, the kernel will boot with 476 very reduced functionality and performance on some platforms that 477 have x2APIC enabled. On the other hand, on hardware that does not 478 support x2APIC, a kernel with this option enabled will just fallback 479 to older APIC implementations. 480 481 If in doubt, say Y. 482 483config X86_POSTED_MSI 484 bool "Enable MSI and MSI-x delivery by posted interrupts" 485 depends on X86_64 && IRQ_REMAP 486 help 487 This enables MSIs that are under interrupt remapping to be delivered as 488 posted interrupts to the host kernel. Interrupt throughput can 489 potentially be improved by coalescing CPU notifications during high 490 frequency bursts. 491 492 If you don't know what to do here, say N. 493 494config X86_MPPARSE 495 bool "Enable MPS table" if ACPI 496 default y 497 depends on X86_LOCAL_APIC 498 help 499 For old smp systems that do not have proper acpi support. Newer systems 500 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 501 502config X86_CPU_RESCTRL 503 bool "x86 CPU resource control support" 504 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 505 depends on MISC_FILESYSTEMS 506 select ARCH_HAS_CPU_RESCTRL 507 select RESCTRL_FS 508 select RESCTRL_FS_PSEUDO_LOCK 509 help 510 Enable x86 CPU resource control support. 511 512 Provide support for the allocation and monitoring of system resources 513 usage by the CPU. 514 515 Intel calls this Intel Resource Director Technology 516 (Intel(R) RDT). More information about RDT can be found in the 517 Intel x86 Architecture Software Developer Manual. 518 519 AMD calls this AMD Platform Quality of Service (AMD QoS). 520 More information about AMD QoS can be found in the AMD64 Technology 521 Platform Quality of Service Extensions manual. 522 523 Say N if unsure. 524 525config X86_FRED 526 bool "Flexible Return and Event Delivery" 527 depends on X86_64 528 help 529 When enabled, try to use Flexible Return and Event Delivery 530 instead of the legacy SYSCALL/SYSENTER/IDT architecture for 531 ring transitions and exception/interrupt handling if the 532 system supports it. 533 534config X86_EXTENDED_PLATFORM 535 bool "Support for extended (non-PC) x86 platforms" 536 default y 537 help 538 If you disable this option then the kernel will only support 539 standard PC platforms. (which covers the vast majority of 540 systems out there.) 541 542 If you enable this option then you'll be able to select support 543 for the following non-PC x86 platforms, depending on the value of 544 CONFIG_64BIT. 545 546 32-bit platforms (CONFIG_64BIT=n): 547 Goldfish (mostly Android emulator) 548 Intel CE media processor (CE4100) SoC 549 Intel Quark 550 RDC R-321x SoC 551 552 64-bit platforms (CONFIG_64BIT=y): 553 Numascale NumaChip 554 ScaleMP vSMP 555 SGI Ultraviolet 556 Merrifield/Moorefield MID devices 557 Goldfish (mostly Android emulator) 558 559 If you have one of these systems, or if you want to build a 560 generic distribution kernel, say Y here - otherwise say N. 561 562# This is an alphabetically sorted list of 64 bit extended platforms 563# Please maintain the alphabetic order if and when there are additions 564config X86_NUMACHIP 565 bool "Numascale NumaChip" 566 depends on X86_64 567 depends on X86_EXTENDED_PLATFORM 568 depends on NUMA 569 depends on SMP 570 depends on X86_X2APIC 571 depends on PCI_MMCONFIG 572 help 573 Adds support for Numascale NumaChip large-SMP systems. Needed to 574 enable more than ~168 cores. 575 If you don't have one of these, you should say N here. 576 577config X86_VSMP 578 bool "ScaleMP vSMP" 579 select HYPERVISOR_GUEST 580 select PARAVIRT 581 depends on X86_64 && PCI 582 depends on X86_EXTENDED_PLATFORM 583 depends on SMP 584 help 585 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 586 supposed to run on these EM64T-based machines. Only choose this option 587 if you have one of these machines. 588 589config X86_UV 590 bool "SGI Ultraviolet" 591 depends on X86_64 592 depends on X86_EXTENDED_PLATFORM 593 depends on NUMA 594 depends on EFI 595 depends on KEXEC_CORE 596 depends on X86_X2APIC 597 depends on PCI 598 help 599 This option is needed in order to support SGI Ultraviolet systems. 600 If you don't have one of these, you should say N here. 601 602config X86_INTEL_MID 603 bool "Intel Z34xx/Z35xx MID platform support" 604 depends on X86_EXTENDED_PLATFORM 605 depends on X86_PLATFORM_DEVICES 606 depends on PCI 607 depends on X86_64 || (EXPERT && PCI_GOANY) 608 depends on X86_IO_APIC 609 select I2C 610 select DW_APB_TIMER 611 select INTEL_SCU_PCI 612 help 613 Select to build a kernel capable of supporting 64-bit Intel MID 614 (Mobile Internet Device) platform systems which do not have 615 the PCI legacy interfaces. 616 617 The only supported devices are the 22nm Merrified (Z34xx) 618 and Moorefield (Z35xx) SoC used in the Intel Edison board and 619 a small number of Android devices such as the Asus Zenfone 2, 620 Asus FonePad 8 and Dell Venue 7. 621 622 If you are building for a PC class system or non-MID tablet 623 SoCs like Bay Trail (Z36xx/Z37xx), say N here. 624 625 Intel MID platforms are based on an Intel processor and chipset which 626 consume less power than most of the x86 derivatives. 627 628config X86_GOLDFISH 629 bool "Goldfish (Virtual Platform)" 630 depends on X86_EXTENDED_PLATFORM 631 help 632 Enable support for the Goldfish virtual platform used primarily 633 for Android development. Unless you are building for the Android 634 Goldfish emulator say N here. 635 636# Following is an alphabetically sorted list of 32 bit extended platforms 637# Please maintain the alphabetic order if and when there are additions 638 639config X86_INTEL_CE 640 bool "CE4100 TV platform" 641 depends on PCI 642 depends on PCI_GODIRECT 643 depends on X86_IO_APIC 644 depends on X86_32 645 depends on X86_EXTENDED_PLATFORM 646 select X86_REBOOTFIXUPS 647 select OF 648 select OF_EARLY_FLATTREE 649 help 650 Select for the Intel CE media processor (CE4100) SOC. 651 This option compiles in support for the CE4100 SOC for settop 652 boxes and media devices. 653 654config X86_INTEL_QUARK 655 bool "Intel Quark platform support" 656 depends on X86_32 657 depends on X86_EXTENDED_PLATFORM 658 depends on X86_PLATFORM_DEVICES 659 depends on X86_TSC 660 depends on PCI 661 depends on PCI_GOANY 662 depends on X86_IO_APIC 663 select IOSF_MBI 664 select INTEL_IMR 665 select COMMON_CLK 666 help 667 Select to include support for Quark X1000 SoC. 668 Say Y here if you have a Quark based system such as the Arduino 669 compatible Intel Galileo. 670 671config X86_RDC321X 672 bool "RDC R-321x SoC" 673 depends on X86_32 674 depends on X86_EXTENDED_PLATFORM 675 select M486 676 select X86_REBOOTFIXUPS 677 help 678 This option is needed for RDC R-321x system-on-chip, also known 679 as R-8610-(G). 680 If you don't have one of these chips, you should say N here. 681 682config X86_INTEL_LPSS 683 bool "Intel Low Power Subsystem Support" 684 depends on X86 && ACPI && PCI 685 select COMMON_CLK 686 select PINCTRL 687 select IOSF_MBI 688 help 689 Select to build support for Intel Low Power Subsystem such as 690 found on Intel Lynxpoint PCH. Selecting this option enables 691 things like clock tree (common clock framework) and pincontrol 692 which are needed by the LPSS peripheral drivers. 693 694config X86_AMD_PLATFORM_DEVICE 695 bool "AMD ACPI2Platform devices support" 696 depends on ACPI 697 select COMMON_CLK 698 select PINCTRL 699 help 700 Select to interpret AMD specific ACPI device to platform device 701 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 702 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 703 implemented under PINCTRL subsystem. 704 705config IOSF_MBI 706 tristate "Intel SoC IOSF Sideband support for SoC platforms" 707 depends on PCI 708 help 709 This option enables sideband register access support for Intel SoC 710 platforms. On these platforms the IOSF sideband is used in lieu of 711 MSR's for some register accesses, mostly but not limited to thermal 712 and power. Drivers may query the availability of this device to 713 determine if they need the sideband in order to work on these 714 platforms. The sideband is available on the following SoC products. 715 This list is not meant to be exclusive. 716 - BayTrail 717 - Braswell 718 - Quark 719 720 You should say Y if you are running a kernel on one of these SoC's. 721 722config IOSF_MBI_DEBUG 723 bool "Enable IOSF sideband access through debugfs" 724 depends on IOSF_MBI && DEBUG_FS 725 help 726 Select this option to expose the IOSF sideband access registers (MCR, 727 MDR, MCRX) through debugfs to write and read register information from 728 different units on the SoC. This is most useful for obtaining device 729 state information for debug and analysis. As this is a general access 730 mechanism, users of this option would have specific knowledge of the 731 device they want to access. 732 733 If you don't require the option or are in doubt, say N. 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 X86_32_IRIS 745 tristate "Eurobraille/Iris poweroff module" 746 depends on X86_32 747 help 748 The Iris machines from EuroBraille do not have APM or ACPI support 749 to shut themselves down properly. A special I/O sequence is 750 needed to do so, which is what this module does at 751 kernel shutdown. 752 753 This is only for Iris machines from EuroBraille. 754 755 If unused, say N. 756 757config SCHED_OMIT_FRAME_POINTER 758 def_bool y 759 prompt "Single-depth WCHAN output" 760 depends on X86 761 help 762 Calculate simpler /proc/<PID>/wchan values. If this option 763 is disabled then wchan values will recurse back to the 764 caller function. This provides more accurate wchan values, 765 at the expense of slightly more scheduling overhead. 766 767 If in doubt, say "Y". 768 769menuconfig HYPERVISOR_GUEST 770 bool "Linux guest support" 771 help 772 Say Y here to enable options for running Linux under various hyper- 773 visors. This option enables basic hypervisor detection and platform 774 setup. 775 776 If you say N, all options in this submenu will be skipped and 777 disabled, and Linux guest support won't be built in. 778 779if HYPERVISOR_GUEST 780 781config PARAVIRT 782 bool "Enable paravirtualization code" 783 depends on HAVE_STATIC_CALL 784 help 785 This changes the kernel so it can modify itself when it is run 786 under a hypervisor, potentially improving performance significantly 787 over full virtualization. However, when run without a hypervisor 788 the kernel is theoretically slower and slightly larger. 789 790config PARAVIRT_XXL 791 bool 792 depends on X86_64 793 794config PARAVIRT_DEBUG 795 bool "paravirt-ops debugging" 796 depends on PARAVIRT && DEBUG_KERNEL 797 help 798 Enable to debug paravirt_ops internals. Specifically, BUG if 799 a paravirt_op is missing when it is called. 800 801config PARAVIRT_SPINLOCKS 802 bool "Paravirtualization layer for spinlocks" 803 depends on PARAVIRT && SMP 804 help 805 Paravirtualized spinlocks allow a pvops backend to replace the 806 spinlock implementation with something virtualization-friendly 807 (for example, block the virtual CPU rather than spinning). 808 809 It has a minimal impact on native kernels and gives a nice performance 810 benefit on paravirtualized KVM / Xen kernels. 811 812 If you are unsure how to answer this question, answer Y. 813 814config X86_HV_CALLBACK_VECTOR 815 def_bool n 816 817source "arch/x86/xen/Kconfig" 818 819config KVM_GUEST 820 bool "KVM Guest support (including kvmclock)" 821 depends on PARAVIRT 822 select PARAVIRT_CLOCK 823 select ARCH_CPUIDLE_HALTPOLL 824 select X86_HV_CALLBACK_VECTOR 825 default y 826 help 827 This option enables various optimizations for running under the KVM 828 hypervisor. It includes a paravirtualized clock, so that instead 829 of relying on a PIT (or probably other) emulation by the 830 underlying device model, the host provides the guest with 831 timing infrastructure such as time of day, and system time 832 833config ARCH_CPUIDLE_HALTPOLL 834 def_bool n 835 prompt "Disable host haltpoll when loading haltpoll driver" 836 help 837 If virtualized under KVM, disable host haltpoll. 838 839config PVH 840 bool "Support for running PVH guests" 841 help 842 This option enables the PVH entry point for guest virtual machines 843 as specified in the x86/HVM direct boot ABI. 844 845config PARAVIRT_TIME_ACCOUNTING 846 bool "Paravirtual steal time accounting" 847 depends on PARAVIRT 848 help 849 Select this option to enable fine granularity task steal time 850 accounting. Time spent executing other tasks in parallel with 851 the current vCPU is discounted from the vCPU power. To account for 852 that, there can be a small performance impact. 853 854 If in doubt, say N here. 855 856config PARAVIRT_CLOCK 857 bool 858 859config JAILHOUSE_GUEST 860 bool "Jailhouse non-root cell support" 861 depends on X86_64 && PCI 862 select X86_PM_TIMER 863 help 864 This option allows to run Linux as guest in a Jailhouse non-root 865 cell. You can leave this option disabled if you only want to start 866 Jailhouse and run Linux afterwards in the root cell. 867 868config ACRN_GUEST 869 bool "ACRN Guest support" 870 depends on X86_64 871 select X86_HV_CALLBACK_VECTOR 872 help 873 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 874 a flexible, lightweight reference open-source hypervisor, built with 875 real-time and safety-criticality in mind. It is built for embedded 876 IOT with small footprint and real-time features. More details can be 877 found in https://projectacrn.org/. 878 879config INTEL_TDX_GUEST 880 bool "Intel TDX (Trust Domain Extensions) - Guest Support" 881 depends on X86_64 && CPU_SUP_INTEL 882 depends on X86_X2APIC 883 depends on EFI_STUB 884 depends on PARAVIRT 885 select ARCH_HAS_CC_PLATFORM 886 select X86_MEM_ENCRYPT 887 select X86_MCE 888 select UNACCEPTED_MEMORY 889 help 890 Support running as a guest under Intel TDX. Without this support, 891 the guest kernel can not boot or run under TDX. 892 TDX includes memory encryption and integrity capabilities 893 which protect the confidentiality and integrity of guest 894 memory contents and CPU state. TDX guests are protected from 895 some attacks from the VMM. 896 897endif # HYPERVISOR_GUEST 898 899source "arch/x86/Kconfig.cpu" 900 901config HPET_TIMER 902 def_bool X86_64 903 prompt "HPET Timer Support" if X86_32 904 help 905 Use the IA-PC HPET (High Precision Event Timer) to manage 906 time in preference to the PIT and RTC, if a HPET is 907 present. 908 HPET is the next generation timer replacing legacy 8254s. 909 The HPET provides a stable time base on SMP 910 systems, unlike the TSC, but it is more expensive to access, 911 as it is off-chip. The interface used is documented 912 in the HPET spec, revision 1. 913 914 You can safely choose Y here. However, HPET will only be 915 activated if the platform and the BIOS support this feature. 916 Otherwise the 8254 will be used for timing services. 917 918 Choose N to continue using the legacy 8254 timer. 919 920config HPET_EMULATE_RTC 921 def_bool y 922 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 923 924# Mark as expert because too many people got it wrong. 925# The code disables itself when not needed. 926config DMI 927 default y 928 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 929 bool "Enable DMI scanning" if EXPERT 930 help 931 Enabled scanning of DMI to identify machine quirks. Say Y 932 here unless you have verified that your setup is not 933 affected by entries in the DMI blacklist. Required by PNP 934 BIOS code. 935 936config GART_IOMMU 937 bool "Old AMD GART IOMMU support" 938 select IOMMU_HELPER 939 select SWIOTLB 940 depends on X86_64 && PCI && AMD_NB 941 help 942 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 943 GART based hardware IOMMUs. 944 945 The GART supports full DMA access for devices with 32-bit access 946 limitations, on systems with more than 3 GB. This is usually needed 947 for USB, sound, many IDE/SATA chipsets and some other devices. 948 949 Newer systems typically have a modern AMD IOMMU, supported via 950 the CONFIG_AMD_IOMMU=y config option. 951 952 In normal configurations this driver is only active when needed: 953 there's more than 3 GB of memory and the system contains a 954 32-bit limited device. 955 956 If unsure, say Y. 957 958config BOOT_VESA_SUPPORT 959 bool 960 help 961 If true, at least one selected framebuffer driver can take advantage 962 of VESA video modes set at an early boot stage via the vga= parameter. 963 964config MAXSMP 965 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 966 depends on X86_64 && SMP && DEBUG_KERNEL 967 select CPUMASK_OFFSTACK 968 help 969 Enable maximum number of CPUS and NUMA Nodes for this architecture. 970 If unsure, say N. 971 972# 973# The maximum number of CPUs supported: 974# 975# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 976# and which can be configured interactively in the 977# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 978# 979# The ranges are different on 32-bit and 64-bit kernels, depending on 980# hardware capabilities and scalability features of the kernel. 981# 982# ( If MAXSMP is enabled we just use the highest possible value and disable 983# interactive configuration. ) 984# 985 986config NR_CPUS_RANGE_BEGIN 987 int 988 default NR_CPUS_RANGE_END if MAXSMP 989 default 1 if !SMP 990 default 2 991 992config NR_CPUS_RANGE_END 993 int 994 depends on X86_32 995 default 8 if SMP 996 default 1 if !SMP 997 998config NR_CPUS_RANGE_END 999 int 1000 depends on X86_64 1001 default 8192 if SMP && CPUMASK_OFFSTACK 1002 default 512 if SMP && !CPUMASK_OFFSTACK 1003 default 1 if !SMP 1004 1005config NR_CPUS_DEFAULT 1006 int 1007 depends on X86_32 1008 default 8 if SMP 1009 default 1 if !SMP 1010 1011config NR_CPUS_DEFAULT 1012 int 1013 depends on X86_64 1014 default 8192 if MAXSMP 1015 default 64 if SMP 1016 default 1 if !SMP 1017 1018config NR_CPUS 1019 int "Maximum number of CPUs" if SMP && !MAXSMP 1020 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1021 default NR_CPUS_DEFAULT 1022 help 1023 This allows you to specify the maximum number of CPUs which this 1024 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1025 supported value is 8192, otherwise the maximum value is 512. The 1026 minimum value which makes sense is 2. 1027 1028 This is purely to save memory: each supported CPU adds about 8KB 1029 to the kernel image. 1030 1031config SCHED_CLUSTER 1032 bool "Cluster scheduler support" 1033 depends on SMP 1034 default y 1035 help 1036 Cluster scheduler support improves the CPU scheduler's decision 1037 making when dealing with machines that have clusters of CPUs. 1038 Cluster usually means a couple of CPUs which are placed closely 1039 by sharing mid-level caches, last-level cache tags or internal 1040 busses. 1041 1042config SCHED_SMT 1043 def_bool y if SMP 1044 1045config SCHED_MC 1046 def_bool y 1047 prompt "Multi-core scheduler support" 1048 depends on SMP 1049 help 1050 Multi-core scheduler support improves the CPU scheduler's decision 1051 making when dealing with multi-core CPU chips at a cost of slightly 1052 increased overhead in some places. If unsure say N here. 1053 1054config SCHED_MC_PRIO 1055 bool "CPU core priorities scheduler support" 1056 depends on SCHED_MC 1057 select X86_INTEL_PSTATE if CPU_SUP_INTEL 1058 select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI 1059 select CPU_FREQ 1060 default y 1061 help 1062 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1063 core ordering determined at manufacturing time, which allows 1064 certain cores to reach higher turbo frequencies (when running 1065 single threaded workloads) than others. 1066 1067 Enabling this kernel feature teaches the scheduler about 1068 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1069 scheduler's CPU selection logic accordingly, so that higher 1070 overall system performance can be achieved. 1071 1072 This feature will have no effect on CPUs without this feature. 1073 1074 If unsure say Y here. 1075 1076config UP_LATE_INIT 1077 def_bool y 1078 depends on !SMP && X86_LOCAL_APIC 1079 1080config X86_UP_APIC 1081 bool "Local APIC support on uniprocessors" if !PCI_MSI 1082 default PCI_MSI 1083 depends on X86_32 && !SMP 1084 help 1085 A local APIC (Advanced Programmable Interrupt Controller) is an 1086 integrated interrupt controller in the CPU. If you have a single-CPU 1087 system which has a processor with a local APIC, you can say Y here to 1088 enable and use it. If you say Y here even though your machine doesn't 1089 have a local APIC, then the kernel will still run with no slowdown at 1090 all. The local APIC supports CPU-generated self-interrupts (timer, 1091 performance counters), and the NMI watchdog which detects hard 1092 lockups. 1093 1094config X86_UP_IOAPIC 1095 bool "IO-APIC support on uniprocessors" 1096 depends on X86_UP_APIC 1097 help 1098 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1099 SMP-capable replacement for PC-style interrupt controllers. Most 1100 SMP systems and many recent uniprocessor systems have one. 1101 1102 If you have a single-CPU system with an IO-APIC, you can say Y here 1103 to use it. If you say Y here even though your machine doesn't have 1104 an IO-APIC, then the kernel will still run with no slowdown at all. 1105 1106config X86_LOCAL_APIC 1107 def_bool y 1108 depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI 1109 select IRQ_DOMAIN_HIERARCHY 1110 1111config ACPI_MADT_WAKEUP 1112 def_bool y 1113 depends on X86_64 1114 depends on ACPI 1115 depends on SMP 1116 depends on X86_LOCAL_APIC 1117 1118config X86_IO_APIC 1119 def_bool y 1120 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1121 1122config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1123 bool "Reroute for broken boot IRQs" 1124 depends on X86_IO_APIC 1125 help 1126 This option enables a workaround that fixes a source of 1127 spurious interrupts. This is recommended when threaded 1128 interrupt handling is used on systems where the generation of 1129 superfluous "boot interrupts" cannot be disabled. 1130 1131 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1132 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1133 kernel does during interrupt handling). On chipsets where this 1134 boot IRQ generation cannot be disabled, this workaround keeps 1135 the original IRQ line masked so that only the equivalent "boot 1136 IRQ" is delivered to the CPUs. The workaround also tells the 1137 kernel to set up the IRQ handler on the boot IRQ line. In this 1138 way only one interrupt is delivered to the kernel. Otherwise 1139 the spurious second interrupt may cause the kernel to bring 1140 down (vital) interrupt lines. 1141 1142 Only affects "broken" chipsets. Interrupt sharing may be 1143 increased on these systems. 1144 1145config X86_MCE 1146 bool "Machine Check / overheating reporting" 1147 select GENERIC_ALLOCATOR 1148 default y 1149 help 1150 Machine Check support allows the processor to notify the 1151 kernel if it detects a problem (e.g. overheating, data corruption). 1152 The action the kernel takes depends on the severity of the problem, 1153 ranging from warning messages to halting the machine. 1154 1155config X86_MCELOG_LEGACY 1156 bool "Support for deprecated /dev/mcelog character device" 1157 depends on X86_MCE 1158 help 1159 Enable support for /dev/mcelog which is needed by the old mcelog 1160 userspace logging daemon. Consider switching to the new generation 1161 rasdaemon solution. 1162 1163config X86_MCE_INTEL 1164 def_bool y 1165 prompt "Intel MCE features" 1166 depends on X86_MCE && X86_LOCAL_APIC 1167 help 1168 Additional support for intel specific MCE features such as 1169 the thermal monitor. 1170 1171config X86_MCE_AMD 1172 def_bool y 1173 prompt "AMD MCE features" 1174 depends on X86_MCE && X86_LOCAL_APIC 1175 help 1176 Additional support for AMD specific MCE features such as 1177 the DRAM Error Threshold. 1178 1179config X86_ANCIENT_MCE 1180 bool "Support for old Pentium 5 / WinChip machine checks" 1181 depends on X86_32 && X86_MCE 1182 help 1183 Include support for machine check handling on old Pentium 5 or WinChip 1184 systems. These typically need to be enabled explicitly on the command 1185 line. 1186 1187config X86_MCE_THRESHOLD 1188 depends on X86_MCE_AMD || X86_MCE_INTEL 1189 def_bool y 1190 1191config X86_MCE_INJECT 1192 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1193 tristate "Machine check injector support" 1194 help 1195 Provide support for injecting machine checks for testing purposes. 1196 If you don't know what a machine check is and you don't do kernel 1197 QA it is safe to say n. 1198 1199source "arch/x86/events/Kconfig" 1200 1201config X86_LEGACY_VM86 1202 bool "Legacy VM86 support" 1203 depends on X86_32 1204 help 1205 This option allows user programs to put the CPU into V8086 1206 mode, which is an 80286-era approximation of 16-bit real mode. 1207 1208 Some very old versions of X and/or vbetool require this option 1209 for user mode setting. Similarly, DOSEMU will use it if 1210 available to accelerate real mode DOS programs. However, any 1211 recent version of DOSEMU, X, or vbetool should be fully 1212 functional even without kernel VM86 support, as they will all 1213 fall back to software emulation. Nevertheless, if you are using 1214 a 16-bit DOS program where 16-bit performance matters, vm86 1215 mode might be faster than emulation and you might want to 1216 enable this option. 1217 1218 Note that any app that works on a 64-bit kernel is unlikely to 1219 need this option, as 64-bit kernels don't, and can't, support 1220 V8086 mode. This option is also unrelated to 16-bit protected 1221 mode and is not needed to run most 16-bit programs under Wine. 1222 1223 Enabling this option increases the complexity of the kernel 1224 and slows down exception handling a tiny bit. 1225 1226 If unsure, say N here. 1227 1228config VM86 1229 bool 1230 default X86_LEGACY_VM86 1231 1232config X86_16BIT 1233 bool "Enable support for 16-bit segments" if EXPERT 1234 default y 1235 depends on MODIFY_LDT_SYSCALL 1236 help 1237 This option is required by programs like Wine to run 16-bit 1238 protected mode legacy code on x86 processors. Disabling 1239 this option saves about 300 bytes on i386, or around 6K text 1240 plus 16K runtime memory on x86-64, 1241 1242config X86_ESPFIX32 1243 def_bool y 1244 depends on X86_16BIT && X86_32 1245 1246config X86_ESPFIX64 1247 def_bool y 1248 depends on X86_16BIT && X86_64 1249 1250config X86_VSYSCALL_EMULATION 1251 bool "Enable vsyscall emulation" if EXPERT 1252 default y 1253 depends on X86_64 1254 help 1255 This enables emulation of the legacy vsyscall page. Disabling 1256 it is roughly equivalent to booting with vsyscall=none, except 1257 that it will also disable the helpful warning if a program 1258 tries to use a vsyscall. With this option set to N, offending 1259 programs will just segfault, citing addresses of the form 1260 0xffffffffff600?00. 1261 1262 This option is required by many programs built before 2013, and 1263 care should be used even with newer programs if set to N. 1264 1265 Disabling this option saves about 7K of kernel size and 1266 possibly 4K of additional runtime pagetable memory. 1267 1268config X86_IOPL_IOPERM 1269 bool "IOPERM and IOPL Emulation" 1270 default y 1271 help 1272 This enables the ioperm() and iopl() syscalls which are necessary 1273 for legacy applications. 1274 1275 Legacy IOPL support is an overbroad mechanism which allows user 1276 space aside of accessing all 65536 I/O ports also to disable 1277 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1278 capabilities and permission from potentially active security 1279 modules. 1280 1281 The emulation restricts the functionality of the syscall to 1282 only allowing the full range I/O port access, but prevents the 1283 ability to disable interrupts from user space which would be 1284 granted if the hardware IOPL mechanism would be used. 1285 1286config TOSHIBA 1287 tristate "Toshiba Laptop support" 1288 depends on X86_32 1289 help 1290 This adds a driver to safely access the System Management Mode of 1291 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1292 not work on models with a Phoenix BIOS. The System Management Mode 1293 is used to set the BIOS and power saving options on Toshiba portables. 1294 1295 For information on utilities to make use of this driver see the 1296 Toshiba Linux utilities web site at: 1297 <http://www.buzzard.org.uk/toshiba/>. 1298 1299 Say Y if you intend to run this kernel on a Toshiba portable. 1300 Say N otherwise. 1301 1302config X86_REBOOTFIXUPS 1303 bool "Enable X86 board specific fixups for reboot" 1304 depends on X86_32 1305 help 1306 This enables chipset and/or board specific fixups to be done 1307 in order to get reboot to work correctly. This is only needed on 1308 some combinations of hardware and BIOS. The symptom, for which 1309 this config is intended, is when reboot ends with a stalled/hung 1310 system. 1311 1312 Currently, the only fixup is for the Geode machines using 1313 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1314 1315 Say Y if you want to enable the fixup. Currently, it's safe to 1316 enable this option even if you don't need it. 1317 Say N otherwise. 1318 1319config MICROCODE 1320 def_bool y 1321 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1322 select CRYPTO_LIB_SHA256 if CPU_SUP_AMD 1323 1324config MICROCODE_INITRD32 1325 def_bool y 1326 depends on MICROCODE && X86_32 && BLK_DEV_INITRD 1327 1328config MICROCODE_LATE_LOADING 1329 bool "Late microcode loading (DANGEROUS)" 1330 default n 1331 depends on MICROCODE && SMP 1332 help 1333 Loading microcode late, when the system is up and executing instructions 1334 is a tricky business and should be avoided if possible. Just the sequence 1335 of synchronizing all cores and SMT threads is one fragile dance which does 1336 not guarantee that cores might not softlock after the loading. Therefore, 1337 use this at your own risk. Late loading taints the kernel unless the 1338 microcode header indicates that it is safe for late loading via the 1339 minimal revision check. This minimal revision check can be enforced on 1340 the kernel command line with "microcode.minrev=Y". 1341 1342config MICROCODE_LATE_FORCE_MINREV 1343 bool "Enforce late microcode loading minimal revision check" 1344 default n 1345 depends on MICROCODE_LATE_LOADING 1346 help 1347 To prevent that users load microcode late which modifies already 1348 in use features, newer microcode patches have a minimum revision field 1349 in the microcode header, which tells the kernel which minimum 1350 revision must be active in the CPU to safely load that new microcode 1351 late into the running system. If disabled the check will not 1352 be enforced but the kernel will be tainted when the minimal 1353 revision check fails. 1354 1355 This minimal revision check can also be controlled via the 1356 "microcode.minrev" parameter on the kernel command line. 1357 1358 If unsure say Y. 1359 1360config X86_MSR 1361 tristate "/dev/cpu/*/msr - Model-specific register support" 1362 help 1363 This device gives privileged processes access to the x86 1364 Model-Specific Registers (MSRs). It is a character device with 1365 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1366 MSR accesses are directed to a specific CPU on multi-processor 1367 systems. 1368 1369config X86_CPUID 1370 tristate "/dev/cpu/*/cpuid - CPU information support" 1371 help 1372 This device gives processes access to the x86 CPUID instruction to 1373 be executed on a specific processor. It is a character device 1374 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1375 /dev/cpu/31/cpuid. 1376 1377config HIGHMEM4G 1378 bool "High Memory Support" 1379 depends on X86_32 1380 help 1381 Linux can use up to 4 Gigabytes of physical memory on x86 systems. 1382 However, the address space of 32-bit x86 processors is only 4 1383 Gigabytes large. That means that, if you have a large amount of 1384 physical memory, not all of it can be "permanently mapped" by the 1385 kernel. The physical memory that's not permanently mapped is called 1386 "high memory". 1387 1388 If you are compiling a kernel which will never run on a machine with 1389 more than 1 Gigabyte total physical RAM, answer "off" here (default 1390 choice and suitable for most users). This will result in a "3GB/1GB" 1391 split: 3GB are mapped so that each process sees a 3GB virtual memory 1392 space and the remaining part of the 4GB virtual memory space is used 1393 by the kernel to permanently map as much physical memory as 1394 possible. 1395 1396 If the machine has between 1 and 4 Gigabytes physical RAM, then 1397 answer "Y" here. 1398 1399 If unsure, say N. 1400 1401choice 1402 prompt "Memory split" if EXPERT 1403 default VMSPLIT_3G 1404 depends on X86_32 1405 help 1406 Select the desired split between kernel and user memory. 1407 1408 If the address range available to the kernel is less than the 1409 physical memory installed, the remaining memory will be available 1410 as "high memory". Accessing high memory is a little more costly 1411 than low memory, as it needs to be mapped into the kernel first. 1412 Note that increasing the kernel address space limits the range 1413 available to user programs, making the address space there 1414 tighter. Selecting anything other than the default 3G/1G split 1415 will also likely make your kernel incompatible with binary-only 1416 kernel modules. 1417 1418 If you are not absolutely sure what you are doing, leave this 1419 option alone! 1420 1421 config VMSPLIT_3G 1422 bool "3G/1G user/kernel split" 1423 config VMSPLIT_3G_OPT 1424 depends on !X86_PAE 1425 bool "3G/1G user/kernel split (for full 1G low memory)" 1426 config VMSPLIT_2G 1427 bool "2G/2G user/kernel split" 1428 config VMSPLIT_2G_OPT 1429 depends on !X86_PAE 1430 bool "2G/2G user/kernel split (for full 2G low memory)" 1431 config VMSPLIT_1G 1432 bool "1G/3G user/kernel split" 1433endchoice 1434 1435config PAGE_OFFSET 1436 hex 1437 default 0xB0000000 if VMSPLIT_3G_OPT 1438 default 0x80000000 if VMSPLIT_2G 1439 default 0x78000000 if VMSPLIT_2G_OPT 1440 default 0x40000000 if VMSPLIT_1G 1441 default 0xC0000000 1442 depends on X86_32 1443 1444config HIGHMEM 1445 def_bool HIGHMEM4G 1446 1447config X86_PAE 1448 bool "PAE (Physical Address Extension) Support" 1449 depends on X86_32 && X86_HAVE_PAE 1450 select PHYS_ADDR_T_64BIT 1451 help 1452 PAE is required for NX support, and furthermore enables 1453 larger swapspace support for non-overcommit purposes. It 1454 has the cost of more pagetable lookup overhead, and also 1455 consumes more pagetable space per process. 1456 1457config X86_DIRECT_GBPAGES 1458 def_bool y 1459 depends on X86_64 1460 help 1461 Certain kernel features effectively disable kernel 1462 linear 1 GB mappings (even if the CPU otherwise 1463 supports them), so don't confuse the user by printing 1464 that we have them enabled. 1465 1466config X86_CPA_STATISTICS 1467 bool "Enable statistic for Change Page Attribute" 1468 depends on DEBUG_FS 1469 help 1470 Expose statistics about the Change Page Attribute mechanism, which 1471 helps to determine the effectiveness of preserving large and huge 1472 page mappings when mapping protections are changed. 1473 1474config X86_MEM_ENCRYPT 1475 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1476 select DYNAMIC_PHYSICAL_MASK 1477 def_bool n 1478 1479config AMD_MEM_ENCRYPT 1480 bool "AMD Secure Memory Encryption (SME) support" 1481 depends on X86_64 && CPU_SUP_AMD 1482 depends on EFI_STUB 1483 select DMA_COHERENT_POOL 1484 select ARCH_USE_MEMREMAP_PROT 1485 select INSTRUCTION_DECODER 1486 select ARCH_HAS_CC_PLATFORM 1487 select X86_MEM_ENCRYPT 1488 select UNACCEPTED_MEMORY 1489 select CRYPTO_LIB_AESGCM 1490 help 1491 Say yes to enable support for the encryption of system memory. 1492 This requires an AMD processor that supports Secure Memory 1493 Encryption (SME). 1494 1495# Common NUMA Features 1496config NUMA 1497 bool "NUMA Memory Allocation and Scheduler Support" 1498 depends on SMP 1499 depends on X86_64 1500 select USE_PERCPU_NUMA_NODE_ID 1501 select OF_NUMA if OF 1502 help 1503 Enable NUMA (Non-Uniform Memory Access) support. 1504 1505 The kernel will try to allocate memory used by a CPU on the 1506 local memory controller of the CPU and add some more 1507 NUMA awareness to the kernel. 1508 1509 For 64-bit this is recommended if the system is Intel Core i7 1510 (or later), AMD Opteron, or EM64T NUMA. 1511 1512 Otherwise, you should say N. 1513 1514config AMD_NUMA 1515 def_bool y 1516 prompt "Old style AMD Opteron NUMA detection" 1517 depends on X86_64 && NUMA && PCI 1518 help 1519 Enable AMD NUMA node topology detection. You should say Y here if 1520 you have a multi processor AMD system. This uses an old method to 1521 read the NUMA configuration directly from the builtin Northbridge 1522 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1523 which also takes priority if both are compiled in. 1524 1525config X86_64_ACPI_NUMA 1526 def_bool y 1527 prompt "ACPI NUMA detection" 1528 depends on X86_64 && NUMA && ACPI && PCI 1529 select ACPI_NUMA 1530 help 1531 Enable ACPI SRAT based node topology detection. 1532 1533config NODES_SHIFT 1534 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1535 range 1 10 1536 default "10" if MAXSMP 1537 default "6" if X86_64 1538 default "3" 1539 depends on NUMA 1540 help 1541 Specify the maximum number of NUMA Nodes available on the target 1542 system. Increases memory reserved to accommodate various tables. 1543 1544config ARCH_FLATMEM_ENABLE 1545 def_bool y 1546 depends on X86_32 && !NUMA 1547 1548config ARCH_SPARSEMEM_ENABLE 1549 def_bool y 1550 select SPARSEMEM_STATIC if X86_32 1551 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1552 select SPARSEMEM_VMEMMAP if X86_64 1553 1554config ARCH_SPARSEMEM_DEFAULT 1555 def_bool X86_64 || (NUMA && X86_32) 1556 1557config ARCH_SELECT_MEMORY_MODEL 1558 def_bool y 1559 depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1560 1561config ARCH_MEMORY_PROBE 1562 bool "Enable sysfs memory/probe interface" 1563 depends on MEMORY_HOTPLUG 1564 help 1565 This option enables a sysfs memory/probe interface for testing. 1566 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1567 If you are unsure how to answer this question, answer N. 1568 1569config ARCH_PROC_KCORE_TEXT 1570 def_bool y 1571 depends on X86_64 && PROC_KCORE 1572 1573config ILLEGAL_POINTER_VALUE 1574 hex 1575 default 0 if X86_32 1576 default 0xdead000000000000 if X86_64 1577 1578config X86_PMEM_LEGACY_DEVICE 1579 bool 1580 1581config X86_PMEM_LEGACY 1582 tristate "Support non-standard NVDIMMs and ADR protected memory" 1583 depends on PHYS_ADDR_T_64BIT 1584 depends on BLK_DEV 1585 select X86_PMEM_LEGACY_DEVICE 1586 select NUMA_KEEP_MEMINFO if NUMA 1587 select LIBNVDIMM 1588 help 1589 Treat memory marked using the non-standard e820 type of 12 as used 1590 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1591 The kernel will offer these regions to the 'pmem' driver so 1592 they can be used for persistent storage. 1593 1594 Say Y if unsure. 1595 1596config X86_CHECK_BIOS_CORRUPTION 1597 bool "Check for low memory corruption" 1598 help 1599 Periodically check for memory corruption in low memory, which 1600 is suspected to be caused by BIOS. Even when enabled in the 1601 configuration, it is disabled at runtime. Enable it by 1602 setting "memory_corruption_check=1" on the kernel command 1603 line. By default it scans the low 64k of memory every 60 1604 seconds; see the memory_corruption_check_size and 1605 memory_corruption_check_period parameters in 1606 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1607 1608 When enabled with the default parameters, this option has 1609 almost no overhead, as it reserves a relatively small amount 1610 of memory and scans it infrequently. It both detects corruption 1611 and prevents it from affecting the running system. 1612 1613 It is, however, intended as a diagnostic tool; if repeatable 1614 BIOS-originated corruption always affects the same memory, 1615 you can use memmap= to prevent the kernel from using that 1616 memory. 1617 1618config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1619 bool "Set the default setting of memory_corruption_check" 1620 depends on X86_CHECK_BIOS_CORRUPTION 1621 default y 1622 help 1623 Set whether the default state of memory_corruption_check is 1624 on or off. 1625 1626config MATH_EMULATION 1627 bool 1628 depends on MODIFY_LDT_SYSCALL 1629 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1630 help 1631 Linux can emulate a math coprocessor (used for floating point 1632 operations) if you don't have one. 486DX and Pentium processors have 1633 a math coprocessor built in, 486SX and 386 do not, unless you added 1634 a 487DX or 387, respectively. (The messages during boot time can 1635 give you some hints here ["man dmesg"].) Everyone needs either a 1636 coprocessor or this emulation. 1637 1638 If you don't have a math coprocessor, you need to say Y here; if you 1639 say Y here even though you have a coprocessor, the coprocessor will 1640 be used nevertheless. (This behavior can be changed with the kernel 1641 command line option "no387", which comes handy if your coprocessor 1642 is broken. Try "man bootparam" or see the documentation of your boot 1643 loader (lilo or loadlin) about how to pass options to the kernel at 1644 boot time.) This means that it is a good idea to say Y here if you 1645 intend to use this kernel on different machines. 1646 1647 More information about the internals of the Linux math coprocessor 1648 emulation can be found in <file:arch/x86/math-emu/README>. 1649 1650 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1651 kernel, it won't hurt. 1652 1653config MTRR 1654 def_bool y 1655 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1656 help 1657 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1658 the Memory Type Range Registers (MTRRs) may be used to control 1659 processor access to memory ranges. This is most useful if you have 1660 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1661 allows bus write transfers to be combined into a larger transfer 1662 before bursting over the PCI/AGP bus. This can increase performance 1663 of image write operations 2.5 times or more. Saying Y here creates a 1664 /proc/mtrr file which may be used to manipulate your processor's 1665 MTRRs. Typically the X server should use this. 1666 1667 This code has a reasonably generic interface so that similar 1668 control registers on other processors can be easily supported 1669 as well: 1670 1671 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1672 Registers (ARRs) which provide a similar functionality to MTRRs. For 1673 these, the ARRs are used to emulate the MTRRs. 1674 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1675 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1676 write-combining. All of these processors are supported by this code 1677 and it makes sense to say Y here if you have one of them. 1678 1679 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1680 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1681 can lead to all sorts of problems, so it's good to say Y here. 1682 1683 You can safely say Y even if your machine doesn't have MTRRs, you'll 1684 just add about 9 KB to your kernel. 1685 1686 See <file:Documentation/arch/x86/mtrr.rst> for more information. 1687 1688config MTRR_SANITIZER 1689 def_bool y 1690 prompt "MTRR cleanup support" 1691 depends on MTRR 1692 help 1693 Convert MTRR layout from continuous to discrete, so X drivers can 1694 add writeback entries. 1695 1696 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1697 The largest mtrr entry size for a continuous block can be set with 1698 mtrr_chunk_size. 1699 1700 If unsure, say Y. 1701 1702config MTRR_SANITIZER_ENABLE_DEFAULT 1703 int "MTRR cleanup enable value (0-1)" 1704 range 0 1 1705 default "0" 1706 depends on MTRR_SANITIZER 1707 help 1708 Enable mtrr cleanup default value 1709 1710config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1711 int "MTRR cleanup spare reg num (0-7)" 1712 range 0 7 1713 default "1" 1714 depends on MTRR_SANITIZER 1715 help 1716 mtrr cleanup spare entries default, it can be changed via 1717 mtrr_spare_reg_nr=N on the kernel command line. 1718 1719config X86_PAT 1720 def_bool y 1721 prompt "x86 PAT support" if EXPERT 1722 depends on MTRR 1723 select ARCH_USES_PG_ARCH_2 1724 help 1725 Use PAT attributes to setup page level cache control. 1726 1727 PATs are the modern equivalents of MTRRs and are much more 1728 flexible than MTRRs. 1729 1730 Say N here if you see bootup problems (boot crash, boot hang, 1731 spontaneous reboots) or a non-working video driver. 1732 1733 If unsure, say Y. 1734 1735config X86_UMIP 1736 def_bool y 1737 prompt "User Mode Instruction Prevention" if EXPERT 1738 help 1739 User Mode Instruction Prevention (UMIP) is a security feature in 1740 some x86 processors. If enabled, a general protection fault is 1741 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1742 executed in user mode. These instructions unnecessarily expose 1743 information about the hardware state. 1744 1745 The vast majority of applications do not use these instructions. 1746 For the very few that do, software emulation is provided in 1747 specific cases in protected and virtual-8086 modes. Emulated 1748 results are dummy. 1749 1750config CC_HAS_IBT 1751 # GCC >= 9 and binutils >= 2.29 1752 # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1753 # Clang/LLVM >= 14 1754 # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1755 # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1756 def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1757 (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1758 $(as-instr,endbr64) 1759 1760config X86_CET 1761 def_bool n 1762 help 1763 CET features configured (Shadow stack or IBT) 1764 1765config X86_KERNEL_IBT 1766 prompt "Indirect Branch Tracking" 1767 def_bool y 1768 depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1769 # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1770 depends on !LD_IS_LLD || LLD_VERSION >= 140000 1771 select OBJTOOL 1772 select X86_CET 1773 help 1774 Build the kernel with support for Indirect Branch Tracking, a 1775 hardware support course-grain forward-edge Control Flow Integrity 1776 protection. It enforces that all indirect calls must land on 1777 an ENDBR instruction, as such, the compiler will instrument the 1778 code with them to make this happen. 1779 1780 In addition to building the kernel with IBT, seal all functions that 1781 are not indirect call targets, avoiding them ever becoming one. 1782 1783 This requires LTO like objtool runs and will slow down the build. It 1784 does significantly reduce the number of ENDBR instructions in the 1785 kernel image. 1786 1787config X86_INTEL_MEMORY_PROTECTION_KEYS 1788 prompt "Memory Protection Keys" 1789 def_bool y 1790 # Note: only available in 64-bit mode 1791 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1792 select ARCH_USES_HIGH_VMA_FLAGS 1793 select ARCH_HAS_PKEYS 1794 help 1795 Memory Protection Keys provides a mechanism for enforcing 1796 page-based protections, but without requiring modification of the 1797 page tables when an application changes protection domains. 1798 1799 For details, see Documentation/core-api/protection-keys.rst 1800 1801 If unsure, say y. 1802 1803config ARCH_PKEY_BITS 1804 int 1805 default 4 1806 1807choice 1808 prompt "TSX enable mode" 1809 depends on CPU_SUP_INTEL 1810 default X86_INTEL_TSX_MODE_OFF 1811 help 1812 Intel's TSX (Transactional Synchronization Extensions) feature 1813 allows to optimize locking protocols through lock elision which 1814 can lead to a noticeable performance boost. 1815 1816 On the other hand it has been shown that TSX can be exploited 1817 to form side channel attacks (e.g. TAA) and chances are there 1818 will be more of those attacks discovered in the future. 1819 1820 Therefore TSX is not enabled by default (aka tsx=off). An admin 1821 might override this decision by tsx=on the command line parameter. 1822 Even with TSX enabled, the kernel will attempt to enable the best 1823 possible TAA mitigation setting depending on the microcode available 1824 for the particular machine. 1825 1826 This option allows to set the default tsx mode between tsx=on, =off 1827 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1828 details. 1829 1830 Say off if not sure, auto if TSX is in use but it should be used on safe 1831 platforms or on if TSX is in use and the security aspect of tsx is not 1832 relevant. 1833 1834config X86_INTEL_TSX_MODE_OFF 1835 bool "off" 1836 help 1837 TSX is disabled if possible - equals to tsx=off command line parameter. 1838 1839config X86_INTEL_TSX_MODE_ON 1840 bool "on" 1841 help 1842 TSX is always enabled on TSX capable HW - equals the tsx=on command 1843 line parameter. 1844 1845config X86_INTEL_TSX_MODE_AUTO 1846 bool "auto" 1847 help 1848 TSX is enabled on TSX capable HW that is believed to be safe against 1849 side channel attacks- equals the tsx=auto command line parameter. 1850endchoice 1851 1852config X86_SGX 1853 bool "Software Guard eXtensions (SGX)" 1854 depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC 1855 select CRYPTO_LIB_SHA256 1856 select MMU_NOTIFIER 1857 select NUMA_KEEP_MEMINFO if NUMA 1858 select XARRAY_MULTI 1859 help 1860 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1861 that can be used by applications to set aside private regions of code 1862 and data, referred to as enclaves. An enclave's private memory can 1863 only be accessed by code running within the enclave. Accesses from 1864 outside the enclave, including other enclaves, are disallowed by 1865 hardware. 1866 1867 If unsure, say N. 1868 1869config X86_USER_SHADOW_STACK 1870 bool "X86 userspace shadow stack" 1871 depends on AS_WRUSS 1872 depends on X86_64 1873 select ARCH_USES_HIGH_VMA_FLAGS 1874 select ARCH_HAS_USER_SHADOW_STACK 1875 select X86_CET 1876 help 1877 Shadow stack protection is a hardware feature that detects function 1878 return address corruption. This helps mitigate ROP attacks. 1879 Applications must be enabled to use it, and old userspace does not 1880 get protection "for free". 1881 1882 CPUs supporting shadow stacks were first released in 2020. 1883 1884 See Documentation/arch/x86/shstk.rst for more information. 1885 1886 If unsure, say N. 1887 1888config INTEL_TDX_HOST 1889 bool "Intel Trust Domain Extensions (TDX) host support" 1890 depends on CPU_SUP_INTEL 1891 depends on X86_64 1892 depends on KVM_INTEL 1893 depends on X86_X2APIC 1894 select ARCH_KEEP_MEMBLOCK 1895 depends on CONTIG_ALLOC 1896 depends on !KEXEC_CORE 1897 depends on X86_MCE 1898 help 1899 Intel Trust Domain Extensions (TDX) protects guest VMs from malicious 1900 host and certain physical attacks. This option enables necessary TDX 1901 support in the host kernel to run confidential VMs. 1902 1903 If unsure, say N. 1904 1905config EFI 1906 bool "EFI runtime service support" 1907 depends on ACPI 1908 select UCS2_STRING 1909 select EFI_RUNTIME_WRAPPERS 1910 select ARCH_USE_MEMREMAP_PROT 1911 select EFI_RUNTIME_MAP if KEXEC_CORE 1912 help 1913 This enables the kernel to use EFI runtime services that are 1914 available (such as the EFI variable services). 1915 1916 This option is only useful on systems that have EFI firmware. 1917 In addition, you should use the latest ELILO loader available 1918 at <http://elilo.sourceforge.net> in order to take advantage 1919 of EFI runtime services. However, even with this option, the 1920 resultant kernel should continue to boot on existing non-EFI 1921 platforms. 1922 1923config EFI_STUB 1924 bool "EFI stub support" 1925 depends on EFI 1926 select RELOCATABLE 1927 help 1928 This kernel feature allows a bzImage to be loaded directly 1929 by EFI firmware without the use of a bootloader. 1930 1931 See Documentation/admin-guide/efi-stub.rst for more information. 1932 1933config EFI_HANDOVER_PROTOCOL 1934 bool "EFI handover protocol (DEPRECATED)" 1935 depends on EFI_STUB 1936 default y 1937 help 1938 Select this in order to include support for the deprecated EFI 1939 handover protocol, which defines alternative entry points into the 1940 EFI stub. This is a practice that has no basis in the UEFI 1941 specification, and requires a priori knowledge on the part of the 1942 bootloader about Linux/x86 specific ways of passing the command line 1943 and initrd, and where in memory those assets may be loaded. 1944 1945 If in doubt, say Y. Even though the corresponding support is not 1946 present in upstream GRUB or other bootloaders, most distros build 1947 GRUB with numerous downstream patches applied, and may rely on the 1948 handover protocol as as result. 1949 1950config EFI_MIXED 1951 bool "EFI mixed-mode support" 1952 depends on EFI_STUB && X86_64 1953 help 1954 Enabling this feature allows a 64-bit kernel to be booted 1955 on a 32-bit firmware, provided that your CPU supports 64-bit 1956 mode. 1957 1958 Note that it is not possible to boot a mixed-mode enabled 1959 kernel via the EFI boot stub - a bootloader that supports 1960 the EFI handover protocol must be used. 1961 1962 If unsure, say N. 1963 1964config EFI_RUNTIME_MAP 1965 bool "Export EFI runtime maps to sysfs" if EXPERT 1966 depends on EFI 1967 help 1968 Export EFI runtime memory regions to /sys/firmware/efi/runtime-map. 1969 That memory map is required by the 2nd kernel to set up EFI virtual 1970 mappings after kexec, but can also be used for debugging purposes. 1971 1972 See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. 1973 1974source "kernel/Kconfig.hz" 1975 1976config ARCH_SUPPORTS_KEXEC 1977 def_bool y 1978 1979config ARCH_SUPPORTS_KEXEC_FILE 1980 def_bool X86_64 1981 1982config ARCH_SELECTS_KEXEC_FILE 1983 def_bool y 1984 depends on KEXEC_FILE 1985 select HAVE_IMA_KEXEC if IMA 1986 1987config ARCH_SUPPORTS_KEXEC_PURGATORY 1988 def_bool y 1989 1990config ARCH_SUPPORTS_KEXEC_SIG 1991 def_bool y 1992 1993config ARCH_SUPPORTS_KEXEC_SIG_FORCE 1994 def_bool y 1995 1996config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG 1997 def_bool y 1998 1999config ARCH_SUPPORTS_KEXEC_JUMP 2000 def_bool y 2001 2002config ARCH_SUPPORTS_KEXEC_HANDOVER 2003 def_bool X86_64 2004 2005config ARCH_SUPPORTS_CRASH_DUMP 2006 def_bool X86_64 || (X86_32 && HIGHMEM) 2007 2008config ARCH_DEFAULT_CRASH_DUMP 2009 def_bool y 2010 2011config ARCH_SUPPORTS_CRASH_HOTPLUG 2012 def_bool y 2013 2014config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION 2015 def_bool CRASH_RESERVE 2016 2017config PHYSICAL_START 2018 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2019 default "0x1000000" 2020 help 2021 This gives the physical address where the kernel is loaded. 2022 2023 If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage 2024 will decompress itself to above physical address and run from there. 2025 Otherwise, bzImage will run from the address where it has been loaded 2026 by the boot loader. The only exception is if it is loaded below the 2027 above physical address, in which case it will relocate itself there. 2028 2029 In normal kdump cases one does not have to set/change this option 2030 as now bzImage can be compiled as a completely relocatable image 2031 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2032 address. This option is mainly useful for the folks who don't want 2033 to use a bzImage for capturing the crash dump and want to use a 2034 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2035 to be specifically compiled to run from a specific memory area 2036 (normally a reserved region) and this option comes handy. 2037 2038 So if you are using bzImage for capturing the crash dump, 2039 leave the value here unchanged to 0x1000000 and set 2040 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2041 for capturing the crash dump change this value to start of 2042 the reserved region. In other words, it can be set based on 2043 the "X" value as specified in the "crashkernel=YM@XM" 2044 command line boot parameter passed to the panic-ed 2045 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2046 for more details about crash dumps. 2047 2048 Usage of bzImage for capturing the crash dump is recommended as 2049 one does not have to build two kernels. Same kernel can be used 2050 as production kernel and capture kernel. Above option should have 2051 gone away after relocatable bzImage support is introduced. But it 2052 is present because there are users out there who continue to use 2053 vmlinux for dump capture. This option should go away down the 2054 line. 2055 2056 Don't change this unless you know what you are doing. 2057 2058config RELOCATABLE 2059 bool "Build a relocatable kernel" 2060 default y 2061 help 2062 This builds a kernel image that retains relocation information 2063 so it can be loaded someplace besides the default 1MB. 2064 The relocations tend to make the kernel binary about 10% larger, 2065 but are discarded at runtime. 2066 2067 One use is for the kexec on panic case where the recovery kernel 2068 must live at a different physical address than the primary 2069 kernel. 2070 2071 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2072 it has been loaded at and the compile time physical address 2073 (CONFIG_PHYSICAL_START) is used as the minimum location. 2074 2075config RANDOMIZE_BASE 2076 bool "Randomize the address of the kernel image (KASLR)" 2077 depends on RELOCATABLE 2078 default y 2079 help 2080 In support of Kernel Address Space Layout Randomization (KASLR), 2081 this randomizes the physical address at which the kernel image 2082 is decompressed and the virtual address where the kernel 2083 image is mapped, as a security feature that deters exploit 2084 attempts relying on knowledge of the location of kernel 2085 code internals. 2086 2087 On 64-bit, the kernel physical and virtual addresses are 2088 randomized separately. The physical address will be anywhere 2089 between 16MB and the top of physical memory (up to 64TB). The 2090 virtual address will be randomized from 16MB up to 1GB (9 bits 2091 of entropy). Note that this also reduces the memory space 2092 available to kernel modules from 1.5GB to 1GB. 2093 2094 On 32-bit, the kernel physical and virtual addresses are 2095 randomized together. They will be randomized from 16MB up to 2096 512MB (8 bits of entropy). 2097 2098 Entropy is generated using the RDRAND instruction if it is 2099 supported. If RDTSC is supported, its value is mixed into 2100 the entropy pool as well. If neither RDRAND nor RDTSC are 2101 supported, then entropy is read from the i8254 timer. The 2102 usable entropy is limited by the kernel being built using 2103 2GB addressing, and that PHYSICAL_ALIGN must be at a 2104 minimum of 2MB. As a result, only 10 bits of entropy are 2105 theoretically possible, but the implementations are further 2106 limited due to memory layouts. 2107 2108 If unsure, say Y. 2109 2110# Relocation on x86 needs some additional build support 2111config X86_NEED_RELOCS 2112 def_bool y 2113 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2114 select ARCH_VMLINUX_NEEDS_RELOCS 2115 2116config PHYSICAL_ALIGN 2117 hex "Alignment value to which kernel should be aligned" 2118 default "0x200000" 2119 range 0x2000 0x1000000 if X86_32 2120 range 0x200000 0x1000000 if X86_64 2121 help 2122 This value puts the alignment restrictions on physical address 2123 where kernel is loaded and run from. Kernel is compiled for an 2124 address which meets above alignment restriction. 2125 2126 If bootloader loads the kernel at a non-aligned address and 2127 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2128 address aligned to above value and run from there. 2129 2130 If bootloader loads the kernel at a non-aligned address and 2131 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2132 load address and decompress itself to the address it has been 2133 compiled for and run from there. The address for which kernel is 2134 compiled already meets above alignment restrictions. Hence the 2135 end result is that kernel runs from a physical address meeting 2136 above alignment restrictions. 2137 2138 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2139 this value must be a multiple of 0x200000. 2140 2141 Don't change this unless you know what you are doing. 2142 2143config RANDOMIZE_MEMORY 2144 bool "Randomize the kernel memory sections" 2145 depends on X86_64 2146 depends on RANDOMIZE_BASE 2147 default RANDOMIZE_BASE 2148 help 2149 Randomizes the base virtual address of kernel memory sections 2150 (physical memory mapping, vmalloc & vmemmap). This security feature 2151 makes exploits relying on predictable memory locations less reliable. 2152 2153 The order of allocations remains unchanged. Entropy is generated in 2154 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2155 configuration have in average 30,000 different possible virtual 2156 addresses for each memory section. 2157 2158 If unsure, say Y. 2159 2160config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2161 hex "Physical memory mapping padding" if EXPERT 2162 depends on RANDOMIZE_MEMORY 2163 default "0xa" if MEMORY_HOTPLUG 2164 default "0x0" 2165 range 0x1 0x40 if MEMORY_HOTPLUG 2166 range 0x0 0x40 2167 help 2168 Define the padding in terabytes added to the existing physical 2169 memory size during kernel memory randomization. It is useful 2170 for memory hotplug support but reduces the entropy available for 2171 address randomization. 2172 2173 If unsure, leave at the default value. 2174 2175config ADDRESS_MASKING 2176 bool "Linear Address Masking support" 2177 depends on X86_64 2178 depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS 2179 help 2180 Linear Address Masking (LAM) modifies the checking that is applied 2181 to 64-bit linear addresses, allowing software to use of the 2182 untranslated address bits for metadata. 2183 2184 The capability can be used for efficient address sanitizers (ASAN) 2185 implementation and for optimizations in JITs. 2186 2187config HOTPLUG_CPU 2188 def_bool y 2189 depends on SMP 2190 2191config COMPAT_VDSO 2192 def_bool n 2193 prompt "Workaround for glibc 2.3.2 / 2.3.3 (released in year 2003/2004)" 2194 depends on COMPAT_32 2195 help 2196 Certain buggy versions of glibc will crash if they are 2197 presented with a 32-bit vDSO that is not mapped at the address 2198 indicated in its segment table. 2199 2200 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2201 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2202 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2203 the only released version with the bug, but OpenSUSE 9 2204 contains a buggy "glibc 2.3.2". 2205 2206 The symptom of the bug is that everything crashes on startup, saying: 2207 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2208 2209 Saying Y here changes the default value of the vdso32 boot 2210 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2211 This works around the glibc bug but hurts performance. 2212 2213 If unsure, say N: if you are compiling your own kernel, you 2214 are unlikely to be using a buggy version of glibc. 2215 2216choice 2217 prompt "vsyscall table for legacy applications" 2218 depends on X86_64 2219 default LEGACY_VSYSCALL_XONLY 2220 help 2221 Legacy user code that does not know how to find the vDSO expects 2222 to be able to issue three syscalls by calling fixed addresses in 2223 kernel space. Since this location is not randomized with ASLR, 2224 it can be used to assist security vulnerability exploitation. 2225 2226 This setting can be changed at boot time via the kernel command 2227 line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2228 is deprecated and can only be enabled using the kernel command 2229 line. 2230 2231 On a system with recent enough glibc (2.14 or newer) and no 2232 static binaries, you can say None without a performance penalty 2233 to improve security. 2234 2235 If unsure, select "Emulate execution only". 2236 2237 config LEGACY_VSYSCALL_XONLY 2238 bool "Emulate execution only" 2239 help 2240 The kernel traps and emulates calls into the fixed vsyscall 2241 address mapping and does not allow reads. This 2242 configuration is recommended when userspace might use the 2243 legacy vsyscall area but support for legacy binary 2244 instrumentation of legacy code is not needed. It mitigates 2245 certain uses of the vsyscall area as an ASLR-bypassing 2246 buffer. 2247 2248 config LEGACY_VSYSCALL_NONE 2249 bool "None" 2250 help 2251 There will be no vsyscall mapping at all. This will 2252 eliminate any risk of ASLR bypass due to the vsyscall 2253 fixed address mapping. Attempts to use the vsyscalls 2254 will be reported to dmesg, so that either old or 2255 malicious userspace programs can be identified. 2256 2257endchoice 2258 2259config CMDLINE_BOOL 2260 bool "Built-in kernel command line" 2261 help 2262 Allow for specifying boot arguments to the kernel at 2263 build time. On some systems (e.g. embedded ones), it is 2264 necessary or convenient to provide some or all of the 2265 kernel boot arguments with the kernel itself (that is, 2266 to not rely on the boot loader to provide them.) 2267 2268 To compile command line arguments into the kernel, 2269 set this option to 'Y', then fill in the 2270 boot arguments in CONFIG_CMDLINE. 2271 2272 Systems with fully functional boot loaders (i.e. non-embedded) 2273 should leave this option set to 'N'. 2274 2275config CMDLINE 2276 string "Built-in kernel command string" 2277 depends on CMDLINE_BOOL 2278 default "" 2279 help 2280 Enter arguments here that should be compiled into the kernel 2281 image and used at boot time. If the boot loader provides a 2282 command line at boot time, it is appended to this string to 2283 form the full kernel command line, when the system boots. 2284 2285 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2286 change this behavior. 2287 2288 In most cases, the command line (whether built-in or provided 2289 by the boot loader) should specify the device for the root 2290 file system. 2291 2292config CMDLINE_OVERRIDE 2293 bool "Built-in command line overrides boot loader arguments" 2294 depends on CMDLINE_BOOL && CMDLINE != "" 2295 help 2296 Set this option to 'Y' to have the kernel ignore the boot loader 2297 command line, and use ONLY the built-in command line. 2298 2299 This is used to work around broken boot loaders. This should 2300 be set to 'N' under normal conditions. 2301 2302config MODIFY_LDT_SYSCALL 2303 bool "Enable the LDT (local descriptor table)" if EXPERT 2304 default y 2305 help 2306 Linux can allow user programs to install a per-process x86 2307 Local Descriptor Table (LDT) using the modify_ldt(2) system 2308 call. This is required to run 16-bit or segmented code such as 2309 DOSEMU or some Wine programs. It is also used by some very old 2310 threading libraries. 2311 2312 Enabling this feature adds a small amount of overhead to 2313 context switches and increases the low-level kernel attack 2314 surface. Disabling it removes the modify_ldt(2) system call. 2315 2316 Saying 'N' here may make sense for embedded or server kernels. 2317 2318config STRICT_SIGALTSTACK_SIZE 2319 bool "Enforce strict size checking for sigaltstack" 2320 depends on DYNAMIC_SIGFRAME 2321 help 2322 For historical reasons MINSIGSTKSZ is a constant which became 2323 already too small with AVX512 support. Add a mechanism to 2324 enforce strict checking of the sigaltstack size against the 2325 real size of the FPU frame. This option enables the check 2326 by default. It can also be controlled via the kernel command 2327 line option 'strict_sas_size' independent of this config 2328 switch. Enabling it might break existing applications which 2329 allocate a too small sigaltstack but 'work' because they 2330 never get a signal delivered. 2331 2332 Say 'N' unless you want to really enforce this check. 2333 2334config CFI_AUTO_DEFAULT 2335 bool "Attempt to use FineIBT by default at boot time" 2336 depends on FINEIBT 2337 depends on !RUST || RUSTC_VERSION >= 108800 2338 default y 2339 help 2340 Attempt to use FineIBT by default at boot time. If enabled, 2341 this is the same as booting with "cfi=auto". If disabled, 2342 this is the same as booting with "cfi=kcfi". 2343 2344source "kernel/livepatch/Kconfig" 2345 2346config X86_BUS_LOCK_DETECT 2347 bool "Split Lock Detect and Bus Lock Detect support" 2348 depends on CPU_SUP_INTEL || CPU_SUP_AMD 2349 default y 2350 help 2351 Enable Split Lock Detect and Bus Lock Detect functionalities. 2352 See <file:Documentation/arch/x86/buslock.rst> for more information. 2353 2354endmenu 2355 2356config CC_HAS_NAMED_AS 2357 def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null) 2358 depends on CC_IS_GCC 2359 2360# 2361# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN) 2362# are incompatible with named address spaces with GCC < 13.3 2363# (see GCC PR sanitizer/111736 and also PR sanitizer/115172). 2364# 2365 2366config CC_HAS_NAMED_AS_FIXED_SANITIZERS 2367 def_bool y 2368 depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300 2369 depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200 2370 2371config USE_X86_SEG_SUPPORT 2372 def_bool CC_HAS_NAMED_AS 2373 depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS 2374 2375config CC_HAS_SLS 2376 def_bool $(cc-option,-mharden-sls=all) 2377 2378config CC_HAS_RETURN_THUNK 2379 def_bool $(cc-option,-mfunction-return=thunk-extern) 2380 2381config CC_HAS_ENTRY_PADDING 2382 def_bool $(cc-option,-fpatchable-function-entry=16,16) 2383 2384config CC_HAS_KCFI_ARITY 2385 def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity) 2386 depends on CC_IS_CLANG && !RUST 2387 2388config FUNCTION_PADDING_CFI 2389 int 2390 default 59 if FUNCTION_ALIGNMENT_64B 2391 default 27 if FUNCTION_ALIGNMENT_32B 2392 default 11 if FUNCTION_ALIGNMENT_16B 2393 default 3 if FUNCTION_ALIGNMENT_8B 2394 default 0 2395 2396# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG 2397# except Kconfig can't do arithmetic :/ 2398config FUNCTION_PADDING_BYTES 2399 int 2400 default FUNCTION_PADDING_CFI if CFI_CLANG 2401 default FUNCTION_ALIGNMENT 2402 2403config CALL_PADDING 2404 def_bool n 2405 depends on CC_HAS_ENTRY_PADDING && OBJTOOL 2406 select FUNCTION_ALIGNMENT_16B 2407 2408config FINEIBT 2409 def_bool y 2410 depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE 2411 select CALL_PADDING 2412 2413config FINEIBT_BHI 2414 def_bool y 2415 depends on FINEIBT && CC_HAS_KCFI_ARITY 2416 2417config HAVE_CALL_THUNKS 2418 def_bool y 2419 depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL 2420 2421config CALL_THUNKS 2422 def_bool n 2423 select CALL_PADDING 2424 2425config PREFIX_SYMBOLS 2426 def_bool y 2427 depends on CALL_PADDING && !CFI_CLANG 2428 2429menuconfig CPU_MITIGATIONS 2430 bool "Mitigations for CPU vulnerabilities" 2431 default y 2432 help 2433 Say Y here to enable options which enable mitigations for hardware 2434 vulnerabilities (usually related to speculative execution). 2435 Mitigations can be disabled or restricted to SMT systems at runtime 2436 via the "mitigations" kernel parameter. 2437 2438 If you say N, all mitigations will be disabled. This CANNOT be 2439 overridden at runtime. 2440 2441 Say 'Y', unless you really know what you are doing. 2442 2443if CPU_MITIGATIONS 2444 2445config MITIGATION_PAGE_TABLE_ISOLATION 2446 bool "Remove the kernel mapping in user mode" 2447 default y 2448 depends on (X86_64 || X86_PAE) 2449 help 2450 This feature reduces the number of hardware side channels by 2451 ensuring that the majority of kernel addresses are not mapped 2452 into userspace. 2453 2454 See Documentation/arch/x86/pti.rst for more details. 2455 2456config MITIGATION_RETPOLINE 2457 bool "Avoid speculative indirect branches in kernel" 2458 select OBJTOOL if HAVE_OBJTOOL 2459 default y 2460 help 2461 Compile kernel with the retpoline compiler options to guard against 2462 kernel-to-user data leaks by avoiding speculative indirect 2463 branches. Requires a compiler with -mindirect-branch=thunk-extern 2464 support for full protection. The kernel may run slower. 2465 2466config MITIGATION_RETHUNK 2467 bool "Enable return-thunks" 2468 depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK 2469 select OBJTOOL if HAVE_OBJTOOL 2470 default y if X86_64 2471 help 2472 Compile the kernel with the return-thunks compiler option to guard 2473 against kernel-to-user data leaks by avoiding return speculation. 2474 Requires a compiler with -mfunction-return=thunk-extern 2475 support for full protection. The kernel may run slower. 2476 2477config MITIGATION_UNRET_ENTRY 2478 bool "Enable UNRET on kernel entry" 2479 depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64 2480 default y 2481 help 2482 Compile the kernel with support for the retbleed=unret mitigation. 2483 2484config MITIGATION_CALL_DEPTH_TRACKING 2485 bool "Mitigate RSB underflow with call depth tracking" 2486 depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS 2487 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 2488 select CALL_THUNKS 2489 default y 2490 help 2491 Compile the kernel with call depth tracking to mitigate the Intel 2492 SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off 2493 by default and needs to be enabled on the kernel command line via the 2494 retbleed=stuff option. For non-affected systems the overhead of this 2495 option is marginal as the call depth tracking is using run-time 2496 generated call thunks in a compiler generated padding area and call 2497 patching. This increases text size by ~5%. For non affected systems 2498 this space is unused. On affected SKL systems this results in a 2499 significant performance gain over the IBRS mitigation. 2500 2501config CALL_THUNKS_DEBUG 2502 bool "Enable call thunks and call depth tracking debugging" 2503 depends on MITIGATION_CALL_DEPTH_TRACKING 2504 select FUNCTION_ALIGNMENT_32B 2505 default n 2506 help 2507 Enable call/ret counters for imbalance detection and build in 2508 a noisy dmesg about callthunks generation and call patching for 2509 trouble shooting. The debug prints need to be enabled on the 2510 kernel command line with 'debug-callthunks'. 2511 Only enable this when you are debugging call thunks as this 2512 creates a noticeable runtime overhead. If unsure say N. 2513 2514config MITIGATION_IBPB_ENTRY 2515 bool "Enable IBPB on kernel entry" 2516 depends on CPU_SUP_AMD && X86_64 2517 default y 2518 help 2519 Compile the kernel with support for the retbleed=ibpb and 2520 spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations. 2521 2522config MITIGATION_IBRS_ENTRY 2523 bool "Enable IBRS on kernel entry" 2524 depends on CPU_SUP_INTEL && X86_64 2525 default y 2526 help 2527 Compile the kernel with support for the spectre_v2=ibrs mitigation. 2528 This mitigates both spectre_v2 and retbleed at great cost to 2529 performance. 2530 2531config MITIGATION_SRSO 2532 bool "Mitigate speculative RAS overflow on AMD" 2533 depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK 2534 default y 2535 help 2536 Enable the SRSO mitigation needed on AMD Zen1-4 machines. 2537 2538config MITIGATION_SLS 2539 bool "Mitigate Straight-Line-Speculation" 2540 depends on CC_HAS_SLS && X86_64 2541 select OBJTOOL if HAVE_OBJTOOL 2542 default n 2543 help 2544 Compile the kernel with straight-line-speculation options to guard 2545 against straight line speculation. The kernel image might be slightly 2546 larger. 2547 2548config MITIGATION_GDS 2549 bool "Mitigate Gather Data Sampling" 2550 depends on CPU_SUP_INTEL 2551 default y 2552 help 2553 Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware 2554 vulnerability which allows unprivileged speculative access to data 2555 which was previously stored in vector registers. The attacker uses gather 2556 instructions to infer the stale vector register data. 2557 2558config MITIGATION_RFDS 2559 bool "RFDS Mitigation" 2560 depends on CPU_SUP_INTEL 2561 default y 2562 help 2563 Enable mitigation for Register File Data Sampling (RFDS) by default. 2564 RFDS is a hardware vulnerability which affects Intel Atom CPUs. It 2565 allows unprivileged speculative access to stale data previously 2566 stored in floating point, vector and integer registers. 2567 See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst> 2568 2569config MITIGATION_SPECTRE_BHI 2570 bool "Mitigate Spectre-BHB (Branch History Injection)" 2571 depends on CPU_SUP_INTEL 2572 default y 2573 help 2574 Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks 2575 where the branch history buffer is poisoned to speculatively steer 2576 indirect branches. 2577 See <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2578 2579config MITIGATION_MDS 2580 bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug" 2581 depends on CPU_SUP_INTEL 2582 default y 2583 help 2584 Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is 2585 a hardware vulnerability which allows unprivileged speculative access 2586 to data which is available in various CPU internal buffers. 2587 See also <file:Documentation/admin-guide/hw-vuln/mds.rst> 2588 2589config MITIGATION_TAA 2590 bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug" 2591 depends on CPU_SUP_INTEL 2592 default y 2593 help 2594 Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware 2595 vulnerability that allows unprivileged speculative access to data 2596 which is available in various CPU internal buffers by using 2597 asynchronous aborts within an Intel TSX transactional region. 2598 See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst> 2599 2600config MITIGATION_MMIO_STALE_DATA 2601 bool "Mitigate MMIO Stale Data hardware bug" 2602 depends on CPU_SUP_INTEL 2603 default y 2604 help 2605 Enable mitigation for MMIO Stale Data hardware bugs. Processor MMIO 2606 Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO) 2607 vulnerabilities that can expose data. The vulnerabilities require the 2608 attacker to have access to MMIO. 2609 See also 2610 <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst> 2611 2612config MITIGATION_L1TF 2613 bool "Mitigate L1 Terminal Fault (L1TF) hardware bug" 2614 depends on CPU_SUP_INTEL 2615 default y 2616 help 2617 Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a 2618 hardware vulnerability which allows unprivileged speculative access to data 2619 available in the Level 1 Data Cache. 2620 See <file:Documentation/admin-guide/hw-vuln/l1tf.rst 2621 2622config MITIGATION_RETBLEED 2623 bool "Mitigate RETBleed hardware bug" 2624 depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY 2625 default y 2626 help 2627 Enable mitigation for RETBleed (Arbitrary Speculative Code Execution 2628 with Return Instructions) vulnerability. RETBleed is a speculative 2629 execution attack which takes advantage of microarchitectural behavior 2630 in many modern microprocessors, similar to Spectre v2. An 2631 unprivileged attacker can use these flaws to bypass conventional 2632 memory security restrictions to gain read access to privileged memory 2633 that would otherwise be inaccessible. 2634 2635config MITIGATION_SPECTRE_V1 2636 bool "Mitigate SPECTRE V1 hardware bug" 2637 default y 2638 help 2639 Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a 2640 class of side channel attacks that takes advantage of speculative 2641 execution that bypasses conditional branch instructions used for 2642 memory access bounds check. 2643 See also <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2644 2645config MITIGATION_SPECTRE_V2 2646 bool "Mitigate SPECTRE V2 hardware bug" 2647 default y 2648 help 2649 Enable mitigation for Spectre V2 (Branch Target Injection). Spectre 2650 V2 is a class of side channel attacks that takes advantage of 2651 indirect branch predictors inside the processor. In Spectre variant 2 2652 attacks, the attacker can steer speculative indirect branches in the 2653 victim to gadget code by poisoning the branch target buffer of a CPU 2654 used for predicting indirect branch addresses. 2655 See also <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2656 2657config MITIGATION_SRBDS 2658 bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug" 2659 depends on CPU_SUP_INTEL 2660 default y 2661 help 2662 Enable mitigation for Special Register Buffer Data Sampling (SRBDS). 2663 SRBDS is a hardware vulnerability that allows Microarchitectural Data 2664 Sampling (MDS) techniques to infer values returned from special 2665 register accesses. An unprivileged user can extract values returned 2666 from RDRAND and RDSEED executed on another core or sibling thread 2667 using MDS techniques. 2668 See also 2669 <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst> 2670 2671config MITIGATION_SSB 2672 bool "Mitigate Speculative Store Bypass (SSB) hardware bug" 2673 default y 2674 help 2675 Enable mitigation for Speculative Store Bypass (SSB). SSB is a 2676 hardware security vulnerability and its exploitation takes advantage 2677 of speculative execution in a similar way to the Meltdown and Spectre 2678 security vulnerabilities. 2679 2680config MITIGATION_ITS 2681 bool "Enable Indirect Target Selection mitigation" 2682 depends on CPU_SUP_INTEL && X86_64 2683 depends on MITIGATION_RETPOLINE && MITIGATION_RETHUNK 2684 select EXECMEM 2685 default y 2686 help 2687 Enable Indirect Target Selection (ITS) mitigation. ITS is a bug in 2688 BPU on some Intel CPUs that may allow Spectre V2 style attacks. If 2689 disabled, mitigation cannot be enabled via cmdline. 2690 See <file:Documentation/admin-guide/hw-vuln/indirect-target-selection.rst> 2691 2692config MITIGATION_TSA 2693 bool "Mitigate Transient Scheduler Attacks" 2694 depends on CPU_SUP_AMD 2695 default y 2696 help 2697 Enable mitigation for Transient Scheduler Attacks. TSA is a hardware 2698 security vulnerability on AMD CPUs which can lead to forwarding of 2699 invalid info to subsequent instructions and thus can affect their 2700 timing and thereby cause a leakage. 2701endif 2702 2703config ARCH_HAS_ADD_PAGES 2704 def_bool y 2705 depends on ARCH_ENABLE_MEMORY_HOTPLUG 2706 2707menu "Power management and ACPI options" 2708 2709config ARCH_HIBERNATION_HEADER 2710 def_bool y 2711 depends on HIBERNATION 2712 2713source "kernel/power/Kconfig" 2714 2715source "drivers/acpi/Kconfig" 2716 2717config X86_APM_BOOT 2718 def_bool y 2719 depends on APM 2720 2721menuconfig APM 2722 tristate "APM (Advanced Power Management) BIOS support" 2723 depends on X86_32 && PM_SLEEP 2724 help 2725 APM is a BIOS specification for saving power using several different 2726 techniques. This is mostly useful for battery powered laptops with 2727 APM compliant BIOSes. If you say Y here, the system time will be 2728 reset after a RESUME operation, the /proc/apm device will provide 2729 battery status information, and user-space programs will receive 2730 notification of APM "events" (e.g. battery status change). 2731 2732 If you select "Y" here, you can disable actual use of the APM 2733 BIOS by passing the "apm=off" option to the kernel at boot time. 2734 2735 Note that the APM support is almost completely disabled for 2736 machines with more than one CPU. 2737 2738 In order to use APM, you will need supporting software. For location 2739 and more information, read <file:Documentation/power/apm-acpi.rst> 2740 and the Battery Powered Linux mini-HOWTO, available from 2741 <http://www.tldp.org/docs.html#howto>. 2742 2743 This driver does not spin down disk drives (see the hdparm(8) 2744 manpage ("man 8 hdparm") for that), and it doesn't turn off 2745 VESA-compliant "green" monitors. 2746 2747 This driver does not support the TI 4000M TravelMate and the ACER 2748 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2749 desktop machines also don't have compliant BIOSes, and this driver 2750 may cause those machines to panic during the boot phase. 2751 2752 Generally, if you don't have a battery in your machine, there isn't 2753 much point in using this driver and you should say N. If you get 2754 random kernel OOPSes or reboots that don't seem to be related to 2755 anything, try disabling/enabling this option (or disabling/enabling 2756 APM in your BIOS). 2757 2758 Some other things you should try when experiencing seemingly random, 2759 "weird" problems: 2760 2761 1) make sure that you have enough swap space and that it is 2762 enabled. 2763 2) pass the "idle=poll" option to the kernel 2764 3) switch on floating point emulation in the kernel and pass 2765 the "no387" option to the kernel 2766 4) pass the "floppy=nodma" option to the kernel 2767 5) pass the "mem=4M" option to the kernel (thereby disabling 2768 all but the first 4 MB of RAM) 2769 6) make sure that the CPU is not over clocked. 2770 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2771 8) disable the cache from your BIOS settings 2772 9) install a fan for the video card or exchange video RAM 2773 10) install a better fan for the CPU 2774 11) exchange RAM chips 2775 12) exchange the motherboard. 2776 2777 To compile this driver as a module, choose M here: the 2778 module will be called apm. 2779 2780if APM 2781 2782config APM_IGNORE_USER_SUSPEND 2783 bool "Ignore USER SUSPEND" 2784 help 2785 This option will ignore USER SUSPEND requests. On machines with a 2786 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2787 series notebooks, it is necessary to say Y because of a BIOS bug. 2788 2789config APM_DO_ENABLE 2790 bool "Enable PM at boot time" 2791 help 2792 Enable APM features at boot time. From page 36 of the APM BIOS 2793 specification: "When disabled, the APM BIOS does not automatically 2794 power manage devices, enter the Standby State, enter the Suspend 2795 State, or take power saving steps in response to CPU Idle calls." 2796 This driver will make CPU Idle calls when Linux is idle (unless this 2797 feature is turned off -- see "Do CPU IDLE calls", below). This 2798 should always save battery power, but more complicated APM features 2799 will be dependent on your BIOS implementation. You may need to turn 2800 this option off if your computer hangs at boot time when using APM 2801 support, or if it beeps continuously instead of suspending. Turn 2802 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2803 T400CDT. This is off by default since most machines do fine without 2804 this feature. 2805 2806config APM_CPU_IDLE 2807 depends on CPU_IDLE 2808 bool "Make CPU Idle calls when idle" 2809 help 2810 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2811 On some machines, this can activate improved power savings, such as 2812 a slowed CPU clock rate, when the machine is idle. These idle calls 2813 are made after the idle loop has run for some length of time (e.g., 2814 333 mS). On some machines, this will cause a hang at boot time or 2815 whenever the CPU becomes idle. (On machines with more than one CPU, 2816 this option does nothing.) 2817 2818config APM_DISPLAY_BLANK 2819 bool "Enable console blanking using APM" 2820 help 2821 Enable console blanking using the APM. Some laptops can use this to 2822 turn off the LCD backlight when the screen blanker of the Linux 2823 virtual console blanks the screen. Note that this is only used by 2824 the virtual console screen blanker, and won't turn off the backlight 2825 when using the X Window system. This also doesn't have anything to 2826 do with your VESA-compliant power-saving monitor. Further, this 2827 option doesn't work for all laptops -- it might not turn off your 2828 backlight at all, or it might print a lot of errors to the console, 2829 especially if you are using gpm. 2830 2831config APM_ALLOW_INTS 2832 bool "Allow interrupts during APM BIOS calls" 2833 help 2834 Normally we disable external interrupts while we are making calls to 2835 the APM BIOS as a measure to lessen the effects of a badly behaving 2836 BIOS implementation. The BIOS should reenable interrupts if it 2837 needs to. Unfortunately, some BIOSes do not -- especially those in 2838 many of the newer IBM Thinkpads. If you experience hangs when you 2839 suspend, try setting this to Y. Otherwise, say N. 2840 2841endif # APM 2842 2843source "drivers/cpufreq/Kconfig" 2844 2845source "drivers/cpuidle/Kconfig" 2846 2847source "drivers/idle/Kconfig" 2848 2849endmenu 2850 2851menu "Bus options (PCI etc.)" 2852 2853choice 2854 prompt "PCI access mode" 2855 depends on X86_32 && PCI 2856 default PCI_GOANY 2857 help 2858 On PCI systems, the BIOS can be used to detect the PCI devices and 2859 determine their configuration. However, some old PCI motherboards 2860 have BIOS bugs and may crash if this is done. Also, some embedded 2861 PCI-based systems don't have any BIOS at all. Linux can also try to 2862 detect the PCI hardware directly without using the BIOS. 2863 2864 With this option, you can specify how Linux should detect the 2865 PCI devices. If you choose "BIOS", the BIOS will be used, 2866 if you choose "Direct", the BIOS won't be used, and if you 2867 choose "MMConfig", then PCI Express MMCONFIG will be used. 2868 If you choose "Any", the kernel will try MMCONFIG, then the 2869 direct access method and falls back to the BIOS if that doesn't 2870 work. If unsure, go with the default, which is "Any". 2871 2872config PCI_GOBIOS 2873 bool "BIOS" 2874 2875config PCI_GOMMCONFIG 2876 bool "MMConfig" 2877 2878config PCI_GODIRECT 2879 bool "Direct" 2880 2881config PCI_GOOLPC 2882 bool "OLPC XO-1" 2883 depends on OLPC 2884 2885config PCI_GOANY 2886 bool "Any" 2887 2888endchoice 2889 2890config PCI_BIOS 2891 def_bool y 2892 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2893 2894# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2895config PCI_DIRECT 2896 def_bool y 2897 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2898 2899config PCI_MMCONFIG 2900 bool "Support mmconfig PCI config space access" if X86_64 2901 default y 2902 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2903 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2904 help 2905 Add support for accessing the PCI configuration space as a memory 2906 mapped area. It is the recommended method if the system supports 2907 this (it must have PCI Express and ACPI for it to be available). 2908 2909 In the unlikely case that enabling this configuration option causes 2910 problems, the mechanism can be switched off with the 'pci=nommconf' 2911 command line parameter. 2912 2913 Say N only if you are sure that your platform does not support this 2914 access method or you have problems caused by it. 2915 2916 Say Y otherwise. 2917 2918config PCI_OLPC 2919 def_bool y 2920 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2921 2922config PCI_XEN 2923 def_bool y 2924 depends on PCI && XEN 2925 2926config MMCONF_FAM10H 2927 def_bool y 2928 depends on X86_64 && PCI_MMCONFIG && ACPI 2929 2930config PCI_CNB20LE_QUIRK 2931 bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT 2932 depends on X86_32 && PCI 2933 help 2934 Read the PCI windows out of the CNB20LE host bridge. This allows 2935 PCI hotplug to work on systems with the CNB20LE chipset which do 2936 not have ACPI. 2937 2938 The ServerWorks (later Broadcom) CNB20LE was a chipset designed 2939 most probably only for Pentium III. 2940 2941 To find out if you have such a chipset, search for a PCI device with 2942 1166:0009 PCI IDs, for example by executing 2943 lspci -nn | grep '1166:0009' 2944 The code is inactive if there is none. 2945 2946 There's no public spec for this chipset, and this functionality 2947 is known to be incomplete. 2948 2949 You should say N unless you know you need this. 2950 2951config ISA_BUS 2952 bool "ISA bus support on modern systems" if EXPERT 2953 help 2954 Expose ISA bus device drivers and options available for selection and 2955 configuration. Enable this option if your target machine has an ISA 2956 bus. ISA is an older system, displaced by PCI and newer bus 2957 architectures -- if your target machine is modern, it probably does 2958 not have an ISA bus. 2959 2960 If unsure, say N. 2961 2962# x86_64 have no ISA slots, but can have ISA-style DMA. 2963config ISA_DMA_API 2964 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2965 default y 2966 help 2967 Enables ISA-style DMA support for devices requiring such controllers. 2968 If unsure, say Y. 2969 2970if X86_32 2971 2972config ISA 2973 bool "ISA support" 2974 help 2975 Find out whether you have ISA slots on your motherboard. ISA is the 2976 name of a bus system, i.e. the way the CPU talks to the other stuff 2977 inside your box. Other bus systems are PCI, EISA, MicroChannel 2978 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2979 newer boards don't support it. If you have ISA, say Y, otherwise N. 2980 2981config SCx200 2982 tristate "NatSemi SCx200 support" 2983 help 2984 This provides basic support for National Semiconductor's 2985 (now AMD's) Geode processors. The driver probes for the 2986 PCI-IDs of several on-chip devices, so its a good dependency 2987 for other scx200_* drivers. 2988 2989 If compiled as a module, the driver is named scx200. 2990 2991config SCx200HR_TIMER 2992 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2993 depends on SCx200 2994 default y 2995 help 2996 This driver provides a clocksource built upon the on-chip 2997 27MHz high-resolution timer. Its also a workaround for 2998 NSC Geode SC-1100's buggy TSC, which loses time when the 2999 processor goes idle (as is done by the scheduler). The 3000 other workaround is idle=poll boot option. 3001 3002config OLPC 3003 bool "One Laptop Per Child support" 3004 depends on !X86_PAE 3005 select GPIOLIB 3006 select OF 3007 select OF_PROMTREE 3008 select IRQ_DOMAIN 3009 select OLPC_EC 3010 help 3011 Add support for detecting the unique features of the OLPC 3012 XO hardware. 3013 3014config OLPC_XO1_PM 3015 bool "OLPC XO-1 Power Management" 3016 depends on OLPC && MFD_CS5535=y && PM_SLEEP 3017 help 3018 Add support for poweroff and suspend of the OLPC XO-1 laptop. 3019 3020config OLPC_XO1_RTC 3021 bool "OLPC XO-1 Real Time Clock" 3022 depends on OLPC_XO1_PM && RTC_DRV_CMOS 3023 help 3024 Add support for the XO-1 real time clock, which can be used as a 3025 programmable wakeup source. 3026 3027config OLPC_XO1_SCI 3028 bool "OLPC XO-1 SCI extras" 3029 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 3030 depends on INPUT=y 3031 select POWER_SUPPLY 3032 help 3033 Add support for SCI-based features of the OLPC XO-1 laptop: 3034 - EC-driven system wakeups 3035 - Power button 3036 - Ebook switch 3037 - Lid switch 3038 - AC adapter status updates 3039 - Battery status updates 3040 3041config OLPC_XO15_SCI 3042 bool "OLPC XO-1.5 SCI extras" 3043 depends on OLPC && ACPI 3044 select POWER_SUPPLY 3045 help 3046 Add support for SCI-based features of the OLPC XO-1.5 laptop: 3047 - EC-driven system wakeups 3048 - AC adapter status updates 3049 - Battery status updates 3050 3051config GEODE_COMMON 3052 bool 3053 3054config ALIX 3055 bool "PCEngines ALIX System Support (LED setup)" 3056 select GPIOLIB 3057 select GEODE_COMMON 3058 help 3059 This option enables system support for the PCEngines ALIX. 3060 At present this just sets up LEDs for GPIO control on 3061 ALIX2/3/6 boards. However, other system specific setup should 3062 get added here. 3063 3064 Note: You must still enable the drivers for GPIO and LED support 3065 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 3066 3067 Note: You have to set alix.force=1 for boards with Award BIOS. 3068 3069config NET5501 3070 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 3071 select GPIOLIB 3072 select GEODE_COMMON 3073 help 3074 This option enables system support for the Soekris Engineering net5501. 3075 3076config GEOS 3077 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 3078 select GPIOLIB 3079 select GEODE_COMMON 3080 depends on DMI 3081 help 3082 This option enables system support for the Traverse Technologies GEOS. 3083 3084config TS5500 3085 bool "Technologic Systems TS-5500 platform support" 3086 depends on MELAN 3087 select CHECK_SIGNATURE 3088 select NEW_LEDS 3089 select LEDS_CLASS 3090 help 3091 This option enables system support for the Technologic Systems TS-5500. 3092 3093endif # X86_32 3094 3095config AMD_NB 3096 def_bool y 3097 depends on AMD_NODE 3098 3099config AMD_NODE 3100 def_bool y 3101 depends on CPU_SUP_AMD && PCI 3102 3103endmenu 3104 3105menu "Binary Emulations" 3106 3107config IA32_EMULATION 3108 bool "IA32 Emulation" 3109 depends on X86_64 3110 select ARCH_WANT_OLD_COMPAT_IPC 3111 select BINFMT_ELF 3112 select COMPAT_OLD_SIGACTION 3113 help 3114 Include code to run legacy 32-bit programs under a 3115 64-bit kernel. You should likely turn this on, unless you're 3116 100% sure that you don't have any 32-bit programs left. 3117 3118config IA32_EMULATION_DEFAULT_DISABLED 3119 bool "IA32 emulation disabled by default" 3120 default n 3121 depends on IA32_EMULATION 3122 help 3123 Make IA32 emulation disabled by default. This prevents loading 32-bit 3124 processes and access to 32-bit syscalls. If unsure, leave it to its 3125 default value. 3126 3127config X86_X32_ABI 3128 bool "x32 ABI for 64-bit mode" 3129 depends on X86_64 3130 # llvm-objcopy does not convert x86_64 .note.gnu.property or 3131 # compressed debug sections to x86_x32 properly: 3132 # https://github.com/ClangBuiltLinux/linux/issues/514 3133 # https://github.com/ClangBuiltLinux/linux/issues/1141 3134 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 3135 help 3136 Include code to run binaries for the x32 native 32-bit ABI 3137 for 64-bit processors. An x32 process gets access to the 3138 full 64-bit register file and wide data path while leaving 3139 pointers at 32 bits for smaller memory footprint. 3140 3141config COMPAT_32 3142 def_bool y 3143 depends on IA32_EMULATION || X86_32 3144 select HAVE_UID16 3145 select OLD_SIGSUSPEND3 3146 3147config COMPAT 3148 def_bool y 3149 depends on IA32_EMULATION || X86_X32_ABI 3150 3151config COMPAT_FOR_U64_ALIGNMENT 3152 def_bool y 3153 depends on COMPAT 3154 3155endmenu 3156 3157config HAVE_ATOMIC_IOMAP 3158 def_bool y 3159 depends on X86_32 3160 3161source "arch/x86/kvm/Kconfig" 3162 3163source "arch/x86/Kconfig.cpufeatures" 3164 3165source "arch/x86/Kconfig.assembler" 3166