1# SPDX-License-Identifier: GPL-2.0 2config MMU 3 def_bool y 4 5config CPU_BIG_ENDIAN 6 def_bool y 7 8config LOCKDEP_SUPPORT 9 def_bool y 10 11config STACKTRACE_SUPPORT 12 def_bool y 13 14config ARCH_HAS_ILOG2_U32 15 def_bool n 16 17config ARCH_HAS_ILOG2_U64 18 def_bool n 19 20config ARCH_PROC_KCORE_TEXT 21 def_bool y 22 23config GENERIC_HWEIGHT 24 def_bool !HAVE_MARCH_Z196_FEATURES 25 26config GENERIC_BUG 27 def_bool y if BUG 28 29config GENERIC_BUG_RELATIVE_POINTERS 30 def_bool y 31 32config GENERIC_LOCKBREAK 33 def_bool y if PREEMPTION 34 35config AUDIT_ARCH 36 def_bool y 37 38config NO_IOPORT_MAP 39 def_bool y 40 41config ARCH_SUPPORTS_UPROBES 42 def_bool y 43 44config KASAN_SHADOW_OFFSET 45 hex 46 depends on KASAN 47 default 0x1C000000000000 48 49config CC_HAS_BUILTIN_FFS 50 def_bool !(CC_IS_GCC && GCC_VERSION < 160000) 51 help 52 GCC versions before 16.0.0 generate library calls to ffs() 53 for __builtin_ffs() even when __has_builtin(__builtin_ffs) 54 is true. 55 56config CC_ASM_FLAG_OUTPUT_BROKEN 57 def_bool CC_IS_GCC && GCC_VERSION < 140200 58 help 59 GCC versions before 14.2.0 may die with an internal 60 compiler error in some configurations if flag output 61 operands are used within inline assemblies. 62 63config CC_HAS_ASM_AOR_FORMAT_FLAGS 64 def_bool !(CC_IS_CLANG && CLANG_VERSION < 190100) 65 help 66 Clang versions before 19.1.0 do not support A, 67 O, and R inline assembly format flags. 68 69config CC_HAS_ASM_IMMEDIATE_STRINGS 70 def_bool !(CC_IS_GCC && GCC_VERSION < 90000) 71 help 72 GCC versions before 9.0.0 cannot handle strings as immediate 73 input operands in inline assemblies. 74 75config CC_HAS_STACKPROTECTOR_GLOBAL 76 def_bool $(cc-option, -mstack-protector-guard=global -mstack-protector-guard-record) 77 78config S390 79 def_bool y 80 # 81 # Note: keep this list sorted alphabetically 82 # 83 imply IMA_SECURE_AND_OR_TRUSTED_BOOT 84 select ALTERNATE_USER_ADDRESS_SPACE 85 select ARCH_32BIT_USTAT_F_TINODE 86 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 87 select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM 88 select ARCH_ENABLE_MEMORY_HOTREMOVE 89 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2 90 select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE 91 select ARCH_HAS_CC_CAN_LINK 92 select ARCH_HAS_CPU_FINALIZE_INIT 93 select ARCH_HAS_CURRENT_STACK_POINTER 94 select ARCH_HAS_DEBUG_VIRTUAL 95 select ARCH_HAS_DEBUG_VM_PGTABLE 96 select ARCH_HAS_DEBUG_WX 97 select ARCH_HAS_DEVMEM_IS_ALLOWED 98 select ARCH_HAS_DMA_OPS if PCI 99 select ARCH_HAS_ELF_RANDOMIZE 100 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 101 select ARCH_HAS_FORTIFY_SOURCE 102 select ARCH_HAS_GCOV_PROFILE_ALL 103 select ARCH_HAS_GIGANTIC_PAGE 104 select ARCH_HAS_KCOV 105 select ARCH_HAS_MEMBARRIER_SYNC_CORE 106 select ARCH_HAS_MEM_ENCRYPT 107 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 108 select ARCH_HAS_PREEMPT_LAZY 109 select ARCH_HAS_PTDUMP 110 select ARCH_HAS_PTE_SPECIAL 111 select ARCH_HAS_SCALED_CPUTIME 112 select ARCH_HAS_SET_DIRECT_MAP 113 select ARCH_HAS_SET_MEMORY 114 select ARCH_HAS_STRICT_KERNEL_RWX 115 select ARCH_HAS_STRICT_MODULE_RWX 116 select ARCH_HAS_SYSCALL_WRAPPER 117 select ARCH_HAS_UBSAN 118 select ARCH_HAS_VDSO_TIME_DATA 119 select ARCH_HAVE_NMI_SAFE_CMPXCHG 120 select ARCH_HAVE_TRACE_MMIO_ACCESS 121 select ARCH_INLINE_READ_LOCK 122 select ARCH_INLINE_READ_LOCK_BH 123 select ARCH_INLINE_READ_LOCK_IRQ 124 select ARCH_INLINE_READ_LOCK_IRQSAVE 125 select ARCH_INLINE_READ_TRYLOCK 126 select ARCH_INLINE_READ_UNLOCK 127 select ARCH_INLINE_READ_UNLOCK_BH 128 select ARCH_INLINE_READ_UNLOCK_IRQ 129 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE 130 select ARCH_INLINE_SPIN_LOCK 131 select ARCH_INLINE_SPIN_LOCK_BH 132 select ARCH_INLINE_SPIN_LOCK_IRQ 133 select ARCH_INLINE_SPIN_LOCK_IRQSAVE 134 select ARCH_INLINE_SPIN_TRYLOCK 135 select ARCH_INLINE_SPIN_TRYLOCK_BH 136 select ARCH_INLINE_SPIN_UNLOCK 137 select ARCH_INLINE_SPIN_UNLOCK_BH 138 select ARCH_INLINE_SPIN_UNLOCK_IRQ 139 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE 140 select ARCH_INLINE_WRITE_LOCK 141 select ARCH_INLINE_WRITE_LOCK_BH 142 select ARCH_INLINE_WRITE_LOCK_IRQ 143 select ARCH_INLINE_WRITE_LOCK_IRQSAVE 144 select ARCH_INLINE_WRITE_TRYLOCK 145 select ARCH_INLINE_WRITE_UNLOCK 146 select ARCH_INLINE_WRITE_UNLOCK_BH 147 select ARCH_INLINE_WRITE_UNLOCK_IRQ 148 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE 149 select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 150 select ARCH_STACKWALK 151 select ARCH_SUPPORTS_ATOMIC_RMW 152 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 153 select ARCH_SUPPORTS_HUGETLBFS 154 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && CC_IS_CLANG 155 select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 156 select ARCH_SUPPORTS_NUMA_BALANCING 157 select ARCH_SUPPORTS_PER_VMA_LOCK 158 select ARCH_USE_BUILTIN_BSWAP 159 select ARCH_USE_CMPXCHG_LOCKREF 160 select ARCH_USE_SYM_ANNOTATIONS 161 select ARCH_WANTS_NO_INSTR 162 select ARCH_WANT_DEFAULT_BPF_JIT 163 select ARCH_WANT_IPC_PARSE_VERSION 164 select ARCH_WANT_IRQS_OFF_ACTIVATE_MM 165 select ARCH_WANT_KERNEL_PMD_MKWRITE 166 select ARCH_WANT_LD_ORPHAN_WARN 167 select ARCH_WANTS_THP_SWAP 168 select BUILDTIME_TABLE_SORT 169 select CLONE_BACKWARDS2 170 select DCACHE_WORD_ACCESS if !KMSAN 171 select DYNAMIC_FTRACE if FUNCTION_TRACER 172 select FUNCTION_ALIGNMENT_8B if CC_IS_GCC 173 select FUNCTION_ALIGNMENT_16B if !CC_IS_GCC 174 select GENERIC_ALLOCATOR 175 select GENERIC_CPU_DEVICES 176 select GENERIC_CPU_AUTOPROBE 177 select GENERIC_CPU_VULNERABILITIES 178 select GENERIC_ENTRY 179 select GENERIC_GETTIMEOFDAY 180 select GENERIC_SMP_IDLE_THREAD 181 select GENERIC_TIME_VSYSCALL 182 select GENERIC_IOREMAP if PCI 183 select HAVE_ALIGNED_STRUCT_PAGE 184 select HAVE_ARCH_AUDITSYSCALL 185 select HAVE_ARCH_JUMP_LABEL 186 select HAVE_ARCH_JUMP_LABEL_RELATIVE 187 select HAVE_ARCH_KASAN 188 select HAVE_ARCH_KASAN_VMALLOC 189 select HAVE_ARCH_KCSAN 190 select HAVE_ARCH_KMSAN 191 select HAVE_ARCH_KFENCE 192 select HAVE_ARCH_KSTACK_ERASE 193 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 194 select HAVE_ARCH_SECCOMP_FILTER 195 select HAVE_ARCH_SOFT_DIRTY 196 select HAVE_ARCH_TRACEHOOK 197 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 198 select HAVE_ARCH_VMAP_STACK 199 select HAVE_ASM_MODVERSIONS 200 select HAVE_BUILDTIME_MCOUNT_SORT 201 select HAVE_CMPXCHG_DOUBLE 202 select HAVE_CMPXCHG_LOCAL 203 select HAVE_DEBUG_KMEMLEAK 204 select HAVE_DMA_CONTIGUOUS 205 select HAVE_DYNAMIC_FTRACE 206 select HAVE_DYNAMIC_FTRACE_WITH_ARGS 207 select HAVE_FTRACE_REGS_HAVING_PT_REGS 208 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 209 select HAVE_DYNAMIC_FTRACE_WITH_REGS 210 select HAVE_EBPF_JIT if HAVE_MARCH_Z196_FEATURES 211 select HAVE_EFFICIENT_UNALIGNED_ACCESS 212 select HAVE_GENERIC_TIF_BITS 213 select HAVE_GUP_FAST 214 select HAVE_FENTRY 215 select HAVE_FTRACE_GRAPH_FUNC 216 select HAVE_FUNCTION_ARG_ACCESS_API 217 select HAVE_FUNCTION_ERROR_INJECTION 218 select HAVE_FUNCTION_GRAPH_FREGS 219 select HAVE_FUNCTION_GRAPH_TRACER 220 select HAVE_FUNCTION_TRACER 221 select HAVE_GCC_PLUGINS 222 select HAVE_GENERIC_VDSO 223 select HAVE_IOREMAP_PROT if PCI 224 select HAVE_KERNEL_BZIP2 225 select HAVE_KERNEL_GZIP 226 select HAVE_KERNEL_LZ4 227 select HAVE_KERNEL_LZMA 228 select HAVE_KERNEL_LZO 229 select HAVE_KERNEL_UNCOMPRESSED 230 select HAVE_KERNEL_XZ 231 select HAVE_KERNEL_ZSTD 232 select HAVE_KPROBES 233 select HAVE_KPROBES_ON_FTRACE 234 select HAVE_KRETPROBES 235 select HAVE_LIVEPATCH 236 select HAVE_MEMBLOCK_PHYS_MAP 237 select HAVE_MOD_ARCH_SPECIFIC 238 select HAVE_NMI 239 select HAVE_NOP_MCOUNT 240 select HAVE_PAGE_SIZE_4KB 241 select HAVE_PCI 242 select HAVE_PERF_EVENTS 243 select HAVE_PERF_REGS 244 select HAVE_PERF_USER_STACK_DUMP 245 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 246 select HAVE_PREEMPT_DYNAMIC_KEY 247 select HAVE_REGS_AND_STACK_ACCESS_API 248 select HAVE_RELIABLE_STACKTRACE 249 select HAVE_RETHOOK 250 select HAVE_RSEQ 251 select HAVE_SAMPLE_FTRACE_DIRECT 252 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI 253 select HAVE_SETUP_PER_CPU_AREA 254 select HAVE_SOFTIRQ_ON_OWN_STACK 255 select HAVE_STACKPROTECTOR if CC_HAS_STACKPROTECTOR_GLOBAL 256 select HAVE_SYSCALL_TRACEPOINTS 257 select HAVE_VIRT_CPU_ACCOUNTING 258 select HAVE_VIRT_CPU_ACCOUNTING_IDLE 259 select HOTPLUG_SMT 260 select IOMMU_HELPER if PCI 261 select IOMMU_SUPPORT if PCI 262 select IRQ_MSI_LIB if PCI 263 select KASAN_VMALLOC if KASAN 264 select LOCK_MM_AND_FIND_VMA 265 select MMU_GATHER_MERGE_VMAS 266 select MMU_GATHER_NO_GATHER 267 select MMU_GATHER_RCU_TABLE_FREE 268 select MODULES_USE_ELF_RELA 269 select NEED_DMA_MAP_STATE if PCI 270 select NEED_PER_CPU_EMBED_FIRST_CHUNK 271 select NEED_PROC_VMCORE_DEVICE_RAM if PROC_VMCORE 272 select NEED_SG_DMA_LENGTH if PCI 273 select OLD_SIGACTION 274 select OLD_SIGSUSPEND3 275 select PCI_DOMAINS if PCI 276 select PCI_MSI if PCI 277 select PCI_MSI_ARCH_FALLBACKS if PCI_MSI 278 select PCI_QUIRKS if PCI 279 select SPARSE_IRQ 280 select SWIOTLB 281 select SYSCTL_EXCEPTION_TRACE 282 select SYSTEM_DATA_VERIFICATION if KEXEC_SIG 283 select THREAD_INFO_IN_TASK 284 select TRACE_IRQFLAGS_SUPPORT 285 select TTY 286 select USER_STACKTRACE_SUPPORT 287 select VDSO_GETRANDOM 288 select VIRT_CPU_ACCOUNTING 289 select VMAP_STACK 290 select ZONE_DMA 291 # Note: keep the above list sorted alphabetically 292 293config SCHED_OMIT_FRAME_POINTER 294 def_bool y 295 296config PGTABLE_LEVELS 297 int 298 default 5 299 300source "kernel/livepatch/Kconfig" 301 302config ARCH_CC_CAN_LINK 303 bool 304 default $(cc_can_link_user,-m64) 305 306config ARCH_USERFLAGS 307 string 308 default "-m64" 309 310config ARCH_SUPPORTS_KEXEC 311 def_bool y 312 313config ARCH_SUPPORTS_KEXEC_FILE 314 def_bool y 315 316config ARCH_SUPPORTS_KEXEC_SIG 317 def_bool y 318 319config ARCH_SUPPORTS_KEXEC_PURGATORY 320 def_bool y 321 322config ARCH_SUPPORTS_CRASH_DUMP 323 def_bool y 324 help 325 Refer to <file:Documentation/arch/s390/zfcpdump.rst> for more details on this. 326 This option also enables s390 zfcpdump. 327 See also <file:Documentation/arch/s390/zfcpdump.rst> 328 329config ARCH_DEFAULT_CRASH_DUMP 330 def_bool y 331 332menu "Processor type and features" 333 334config HAVE_MARCH_Z10_FEATURES 335 def_bool n 336 337config HAVE_MARCH_Z196_FEATURES 338 def_bool n 339 select HAVE_MARCH_Z10_FEATURES 340 341config HAVE_MARCH_ZEC12_FEATURES 342 def_bool n 343 select HAVE_MARCH_Z196_FEATURES 344 345config HAVE_MARCH_Z13_FEATURES 346 def_bool n 347 select HAVE_MARCH_ZEC12_FEATURES 348 349config HAVE_MARCH_Z14_FEATURES 350 def_bool n 351 select HAVE_MARCH_Z13_FEATURES 352 353config HAVE_MARCH_Z15_FEATURES 354 def_bool n 355 select HAVE_MARCH_Z14_FEATURES 356 357config HAVE_MARCH_Z16_FEATURES 358 def_bool n 359 select HAVE_MARCH_Z15_FEATURES 360 361config HAVE_MARCH_Z17_FEATURES 362 def_bool n 363 select HAVE_MARCH_Z16_FEATURES 364 365choice 366 prompt "Processor type" 367 default MARCH_Z196 368 369config MARCH_Z10 370 bool "IBM System z10" 371 select HAVE_MARCH_Z10_FEATURES 372 depends on $(cc-option,-march=z10) 373 help 374 Select this to enable optimizations for IBM System z10 (2097 and 2098 375 series). This is the oldest machine generation currently supported. 376 377config MARCH_Z196 378 bool "IBM zEnterprise 114 and 196" 379 select HAVE_MARCH_Z196_FEATURES 380 depends on $(cc-option,-march=z196) 381 help 382 Select this to enable optimizations for IBM zEnterprise 114 and 196 383 (2818 and 2817 series). The kernel will be slightly faster but will 384 not work on older machines. 385 386config MARCH_ZEC12 387 bool "IBM zBC12 and zEC12" 388 select HAVE_MARCH_ZEC12_FEATURES 389 depends on $(cc-option,-march=zEC12) 390 help 391 Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and 392 2827 series). The kernel will be slightly faster but will not work on 393 older machines. 394 395config MARCH_Z13 396 bool "IBM z13s and z13" 397 select HAVE_MARCH_Z13_FEATURES 398 depends on $(cc-option,-march=z13) 399 help 400 Select this to enable optimizations for IBM z13s and z13 (2965 and 401 2964 series). The kernel will be slightly faster but will not work on 402 older machines. 403 404config MARCH_Z14 405 bool "IBM z14 ZR1 and z14" 406 select HAVE_MARCH_Z14_FEATURES 407 depends on $(cc-option,-march=z14) 408 help 409 Select this to enable optimizations for IBM z14 ZR1 and z14 (3907 410 and 3906 series). The kernel will be slightly faster but will not 411 work on older machines. 412 413config MARCH_Z15 414 bool "IBM z15" 415 select HAVE_MARCH_Z15_FEATURES 416 depends on $(cc-option,-march=z15) 417 help 418 Select this to enable optimizations for IBM z15 (8562 419 and 8561 series). The kernel will be slightly faster but will not 420 work on older machines. 421 422config MARCH_Z16 423 bool "IBM z16" 424 select HAVE_MARCH_Z16_FEATURES 425 depends on $(cc-option,-march=z16) 426 help 427 Select this to enable optimizations for IBM z16 (3931 and 428 3932 series). 429 430config MARCH_Z17 431 bool "IBM z17" 432 select HAVE_MARCH_Z17_FEATURES 433 depends on $(cc-option,-march=z17) 434 help 435 Select this to enable optimizations for IBM z17 (9175 and 436 9176 series). 437 438endchoice 439 440config MARCH_Z10_TUNE 441 def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT 442 443config MARCH_Z196_TUNE 444 def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT 445 446config MARCH_ZEC12_TUNE 447 def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT 448 449config MARCH_Z13_TUNE 450 def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT 451 452config MARCH_Z14_TUNE 453 def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT 454 455config MARCH_Z15_TUNE 456 def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT 457 458config MARCH_Z16_TUNE 459 def_bool TUNE_Z16 || MARCH_Z16 && TUNE_DEFAULT 460 461config MARCH_Z17_TUNE 462 def_bool TUNE_Z17 || MARCH_Z17 && TUNE_DEFAULT 463 464choice 465 prompt "Tune code generation" 466 default TUNE_DEFAULT 467 help 468 Cause the compiler to tune (-mtune) the generated code for a machine. 469 This will make the code run faster on the selected machine but 470 somewhat slower on other machines. 471 This option only changes how the compiler emits instructions, not the 472 selection of instructions itself, so the resulting kernel will run on 473 all other machines. 474 475config TUNE_DEFAULT 476 bool "Default" 477 help 478 Tune the generated code for the target processor for which the kernel 479 will be compiled. 480 481config TUNE_Z10 482 bool "IBM System z10" 483 484config TUNE_Z196 485 bool "IBM zEnterprise 114 and 196" 486 depends on $(cc-option,-mtune=z196) 487 488config TUNE_ZEC12 489 bool "IBM zBC12 and zEC12" 490 depends on $(cc-option,-mtune=zEC12) 491 492config TUNE_Z13 493 bool "IBM z13s and z13" 494 depends on $(cc-option,-mtune=z13) 495 496config TUNE_Z14 497 bool "IBM z14 ZR1 and z14" 498 depends on $(cc-option,-mtune=z14) 499 500config TUNE_Z15 501 bool "IBM z15" 502 depends on $(cc-option,-mtune=z15) 503 504config TUNE_Z16 505 bool "IBM z16" 506 depends on $(cc-option,-mtune=z16) 507 508config TUNE_Z17 509 bool "IBM z17" 510 depends on $(cc-option,-mtune=z17) 511 512endchoice 513 514config 64BIT 515 def_bool y 516 517config COMMAND_LINE_SIZE 518 int "Maximum size of kernel command line" 519 default 4096 520 range 896 1048576 521 help 522 This allows you to specify the maximum length of the kernel command 523 line. 524 525config SMP 526 def_bool y 527 528config NR_CPUS 529 int "Maximum number of CPUs (2-512)" 530 range 2 512 531 default "64" 532 help 533 This allows you to specify the maximum number of CPUs which this 534 kernel will support. The maximum supported value is 512 and the 535 minimum value which makes sense is 2. 536 537 This is purely to save memory - each supported CPU adds 538 approximately sixteen kilobytes to the kernel image. 539 540config HOTPLUG_CPU 541 def_bool y 542 543config NUMA 544 bool "NUMA support" 545 depends on SCHED_TOPOLOGY 546 default n 547 help 548 Enable NUMA support 549 550 This option adds NUMA support to the kernel. 551 552config NODES_SHIFT 553 int 554 depends on NUMA 555 default "1" 556 557config SCHED_TOPOLOGY 558 def_bool y 559 prompt "Topology scheduler support" 560 select ARCH_SUPPORTS_SCHED_SMT 561 select ARCH_SUPPORTS_SCHED_MC 562 select SCHED_SMT 563 select SCHED_MC 564 help 565 Topology scheduler support improves the CPU scheduler's decision 566 making when dealing with machines that have multi-threading, 567 multiple cores or multiple books. 568 569config SCHED_TOPOLOGY_VERTICAL 570 def_bool y 571 bool "Use vertical CPU polarization by default" 572 depends on SCHED_TOPOLOGY 573 help 574 Use vertical CPU polarization by default if available. 575 The default CPU polarization is horizontal. 576 577config HIPERDISPATCH_ON 578 def_bool y 579 bool "Use hiperdispatch on vertical polarization by default" 580 depends on SCHED_TOPOLOGY 581 depends on PROC_SYSCTL 582 help 583 Hiperdispatch aims to improve the CPU scheduler's decision 584 making when using vertical polarization by adjusting CPU 585 capacities dynamically. Set this option to use hiperdispatch 586 on vertical polarization by default. This can be overwritten 587 by sysctl's s390.hiperdispatch attribute later on. 588 589source "kernel/Kconfig.hz" 590 591config CERT_STORE 592 bool "Get user certificates via DIAG320" 593 depends on KEYS 594 select CRYPTO_LIB_SHA256 595 help 596 Enable this option if you want to access user-provided secure boot 597 certificates via DIAG 0x320. 598 599 These certificates will be made available via the keyring named 600 'cert_store'. 601 602config KERNEL_NOBP 603 def_bool n 604 prompt "Enable modified branch prediction for the kernel by default" 605 help 606 If this option is selected the kernel will switch to a modified 607 branch prediction mode if the firmware interface is available. 608 The modified branch prediction mode improves the behaviour in 609 regard to speculative execution. 610 611 With the option enabled the kernel parameter "nobp=0" or "nospec" 612 can be used to run the kernel in the normal branch prediction mode. 613 614 With the option disabled the modified branch prediction mode is 615 enabled with the "nobp=1" kernel parameter. 616 617 If unsure, say N. 618 619config EXPOLINE 620 def_bool n 621 depends on $(cc-option,-mindirect-branch=thunk) 622 prompt "Avoid speculative indirect branches in the kernel" 623 help 624 Compile the kernel with the expoline compiler options to guard 625 against kernel-to-user data leaks by avoiding speculative indirect 626 branches. 627 Requires a compiler with -mindirect-branch=thunk support for full 628 protection. The kernel may run slower. 629 630 If unsure, say N. 631 632config EXPOLINE_EXTERN 633 def_bool EXPOLINE && CC_IS_GCC && GCC_VERSION >= 110200 && \ 634 $(success,$(srctree)/arch/s390/tools/gcc-thunk-extern.sh $(CC)) 635 help 636 Generate expolines as external functions if the compiler supports it. 637 This option is required for some tooling like kpatch, if expolines 638 are enabled. The kernel is compiled with 639 -mindirect-branch=thunk-extern, which requires a newer compiler. 640 641choice 642 prompt "Expoline default" 643 depends on EXPOLINE 644 default EXPOLINE_FULL 645 646config EXPOLINE_OFF 647 bool "spectre_v2=off" 648 649config EXPOLINE_AUTO 650 bool "spectre_v2=auto" 651 652config EXPOLINE_FULL 653 bool "spectre_v2=on" 654 655endchoice 656 657config RELOCATABLE 658 def_bool y 659 select ARCH_VMLINUX_NEEDS_RELOCS 660 help 661 This builds a kernel image that retains relocation information 662 so it can be loaded at an arbitrary address. 663 The relocations make the kernel image about 15% larger (compressed 664 10%), but are discarded at runtime. 665 Note: this option exists only for documentation purposes, please do 666 not remove it. 667 668config RANDOMIZE_BASE 669 bool "Randomize the address of the kernel image (KASLR)" 670 default y 671 help 672 In support of Kernel Address Space Layout Randomization (KASLR), 673 this randomizes the address at which the kernel image is loaded, 674 as a security feature that deters exploit attempts relying on 675 knowledge of the location of kernel internals. 676 677config RANDOMIZE_IDENTITY_BASE 678 bool "Randomize the address of the identity mapping base" 679 depends on RANDOMIZE_BASE 680 default DEBUG_VM 681 help 682 The identity mapping base address is pinned to zero by default. 683 Allow randomization of that base to expose otherwise missed 684 notion of physical and virtual addresses of data structures. 685 That does not have any impact on the base address at which the 686 kernel image is loaded. 687 688 If unsure, say N 689 690config KERNEL_IMAGE_BASE 691 hex "Kernel image base address" 692 range 0x100000 0x1FFFFFE0000000 if !KASAN 693 range 0x100000 0x1BFFFFE0000000 if KASAN 694 default 0x3FFE0000000 if !KASAN 695 default 0x7FFFE0000000 if KASAN 696 help 697 This is the address at which the kernel image is loaded in case 698 Kernel Address Space Layout Randomization (KASLR) is disabled. 699 700 In case the Protected virtualization guest support is enabled the 701 Ultravisor imposes a virtual address limit. If the value of this 702 option leads to the kernel image exceeding the Ultravisor limit, 703 this option is ignored and the image is loaded below the limit. 704 705 If the value of this option leads to the kernel image overlapping 706 the virtual memory where other data structures are located, this 707 option is ignored and the image is loaded above the structures. 708 709endmenu 710 711menu "Memory setup" 712 713config ARCH_SPARSEMEM_ENABLE 714 def_bool y 715 select SPARSEMEM_VMEMMAP_ENABLE 716 717config ARCH_SPARSEMEM_DEFAULT 718 def_bool y 719 720config ILLEGAL_POINTER_VALUE 721 hex 722 default 0xdead000000000000 723 724config MAX_PHYSMEM_BITS 725 int "Maximum size of supported physical memory in bits (42-53)" 726 range 42 53 727 default "46" 728 help 729 This option specifies the maximum supported size of physical memory 730 in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB). 731 Increasing the number of bits also increases the kernel image size. 732 By default 46 bits (64TB) are supported. 733 734endmenu 735 736menu "I/O subsystem" 737 738config QDIO 739 def_tristate y 740 prompt "QDIO support" 741 help 742 This driver provides the Queued Direct I/O base support for 743 IBM System z. 744 745 To compile this driver as a module, choose M here: the 746 module will be called qdio. 747 748 If unsure, say Y. 749 750if PCI 751 752config PCI_NR_FUNCTIONS 753 int "Maximum number of PCI functions (1-4096)" 754 range 1 4096 755 default "512" 756 help 757 This allows you to specify the maximum number of PCI functions which 758 this kernel will support. 759 760endif # PCI 761 762config HAS_IOMEM 763 def_bool PCI 764 765config CHSC_SCH 766 def_tristate m 767 prompt "Support for CHSC subchannels" 768 help 769 This driver allows usage of CHSC subchannels. A CHSC subchannel 770 is usually present on LPAR only. 771 The driver creates a device /dev/chsc, which may be used to 772 obtain I/O configuration information about the machine and 773 to issue asynchronous chsc commands (DANGEROUS). 774 You will usually only want to use this interface on a special 775 LPAR designated for system management. 776 777 To compile this driver as a module, choose M here: the 778 module will be called chsc_sch. 779 780 If unsure, say N. 781 782config SCM_BUS 783 def_bool y 784 prompt "SCM bus driver" 785 help 786 Bus driver for Storage Class Memory. 787 788config EADM_SCH 789 def_tristate m 790 prompt "Support for EADM subchannels" 791 depends on SCM_BUS 792 help 793 This driver allows usage of EADM subchannels. EADM subchannels act 794 as a communication vehicle for SCM increments. 795 796 To compile this driver as a module, choose M here: the 797 module will be called eadm_sch. 798 799config AP 800 def_tristate y 801 prompt "Support for Adjunct Processors (ap)" 802 help 803 This driver allows usage to Adjunct Processor (AP) devices via 804 the ap bus, cards and queues. Supported Adjunct Processors are 805 the CryptoExpress Cards (CEX). 806 807 To compile this driver as a module, choose M here: the 808 module will be called ap. 809 810 If unsure, say Y (default). 811 812config AP_DEBUG 813 def_bool n 814 prompt "Enable debug features for Adjunct Processor (ap) devices" 815 depends on AP 816 help 817 Say 'Y' here to enable some additional debug features for Adjunct 818 Processor (ap) devices. 819 820 There will be some more sysfs attributes displayed for ap queues. 821 822 Do not enable on production level kernel build. 823 824 If unsure, say N. 825 826config VFIO_CCW 827 def_tristate n 828 prompt "Support for VFIO-CCW subchannels" 829 depends on VFIO 830 select VFIO_MDEV 831 help 832 This driver allows usage of I/O subchannels via VFIO-CCW. 833 834 To compile this driver as a module, choose M here: the 835 module will be called vfio_ccw. 836 837config VFIO_AP 838 def_tristate n 839 prompt "VFIO support for AP devices" 840 depends on KVM 841 depends on VFIO 842 depends on AP 843 select VFIO_MDEV 844 help 845 This driver grants access to Adjunct Processor (AP) devices 846 via the VFIO mediated device interface. 847 848 To compile this driver as a module, choose M here: the module 849 will be called vfio_ap. 850 851endmenu 852 853config CCW 854 def_bool y 855 856config HAVE_PNETID 857 tristate 858 default (SMC || CCWGROUP) 859 860menu "Virtualization" 861 862config PFAULT 863 def_bool y 864 prompt "Pseudo page fault support" 865 help 866 Select this option, if you want to use PFAULT pseudo page fault 867 handling under VM. If running native or in LPAR, this option 868 has no effect. If your VM does not support PFAULT, PAGEEX 869 pseudo page fault handling will be used. 870 Note that VM 4.2 supports PFAULT but has a bug in its 871 implementation that causes some problems. 872 Everybody who wants to run Linux under VM != VM4.2 should select 873 this option. 874 875config CMM 876 def_tristate n 877 prompt "Cooperative memory management" 878 help 879 Select this option, if you want to enable the kernel interface 880 to reduce the memory size of the system. This is accomplished 881 by allocating pages of memory and put them "on hold". This only 882 makes sense for a system running under VM where the unused pages 883 will be reused by VM for other guest systems. The interface 884 allows an external monitor to balance memory of many systems. 885 Everybody who wants to run Linux under VM should select this 886 option. 887 888config CMM_IUCV 889 def_bool y 890 prompt "IUCV special message interface to cooperative memory management" 891 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV) 892 help 893 Select this option to enable the special message interface to 894 the cooperative memory management. 895 896config APPLDATA_BASE 897 def_bool n 898 prompt "Linux - VM Monitor Stream, base infrastructure" 899 depends on PROC_SYSCTL 900 help 901 This provides a kernel interface for creating and updating z/VM APPLDATA 902 monitor records. The monitor records are updated at certain time 903 intervals, once the timer is started. 904 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer, 905 i.e. enables or disables monitoring on the Linux side. 906 A custom interval value (in seconds) can be written to 907 /proc/appldata/interval. 908 909 Defaults are 60 seconds interval and timer off. 910 The /proc entries can also be read from, showing the current settings. 911 912config APPLDATA_MEM 913 def_tristate m 914 prompt "Monitor memory management statistics" 915 depends on APPLDATA_BASE && VM_EVENT_COUNTERS 916 help 917 This provides memory management related data to the Linux - VM Monitor 918 Stream, like paging/swapping rate, memory utilisation, etc. 919 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM 920 APPLDATA monitor record, i.e. enables or disables monitoring this record 921 on the z/VM side. 922 923 Default is disabled. 924 The /proc entry can also be read from, showing the current settings. 925 926 This can also be compiled as a module, which will be called 927 appldata_mem.o. 928 929config APPLDATA_OS 930 def_tristate m 931 prompt "Monitor OS statistics" 932 depends on APPLDATA_BASE 933 help 934 This provides OS related data to the Linux - VM Monitor Stream, like 935 CPU utilisation, etc. 936 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM 937 APPLDATA monitor record, i.e. enables or disables monitoring this record 938 on the z/VM side. 939 940 Default is disabled. 941 This can also be compiled as a module, which will be called 942 appldata_os.o. 943 944config APPLDATA_NET_SUM 945 def_tristate m 946 prompt "Monitor overall network statistics" 947 depends on APPLDATA_BASE && NET 948 help 949 This provides network related data to the Linux - VM Monitor Stream, 950 currently there is only a total sum of network I/O statistics, no 951 per-interface data. 952 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM 953 APPLDATA monitor record, i.e. enables or disables monitoring this record 954 on the z/VM side. 955 956 Default is disabled. 957 This can also be compiled as a module, which will be called 958 appldata_net_sum.o. 959 960config S390_HYPFS 961 def_bool y 962 prompt "s390 hypervisor information" 963 help 964 This provides several binary files at (debugfs)/s390_hypfs/ to 965 provide accounting information in an s390 hypervisor environment. 966 967config S390_HYPFS_FS 968 def_bool n 969 prompt "s390 hypervisor file system support" 970 select SYS_HYPERVISOR 971 depends on S390_HYPFS 972 help 973 This is a virtual file system intended to provide accounting 974 information in an s390 hypervisor environment. This file system 975 is deprecated and should not be used. 976 977 Say N if you are unsure. 978 979source "arch/s390/kvm/Kconfig" 980 981config S390_GUEST 982 def_bool y 983 prompt "s390 support for virtio devices" 984 select TTY 985 select VIRTUALIZATION 986 select VIRTIO 987 help 988 Enabling this option adds support for virtio based paravirtual device 989 drivers on s390. 990 991 Select this option if you want to run the kernel as a guest under 992 the KVM hypervisor. 993 994endmenu 995 996config S390_MODULES_SANITY_TEST_HELPERS 997 def_bool n 998 999menu "Selftests" 1000 1001config S390_UNWIND_SELFTEST 1002 def_tristate n 1003 depends on KUNIT 1004 default KUNIT_ALL_TESTS 1005 prompt "Test unwind functions" 1006 help 1007 This option enables s390 specific stack unwinder testing kernel 1008 module. This option is not useful for distributions or general 1009 kernels, but only for kernel developers working on architecture code. 1010 1011 Say N if you are unsure. 1012 1013config S390_KPROBES_SANITY_TEST 1014 def_tristate n 1015 prompt "Enable s390 specific kprobes tests" 1016 depends on KPROBES 1017 depends on KUNIT 1018 help 1019 This option enables an s390 specific kprobes test module. This option 1020 is not useful for distributions or general kernels, but only for kernel 1021 developers working on architecture code. 1022 1023 Say N if you are unsure. 1024 1025config S390_MODULES_SANITY_TEST 1026 def_tristate n 1027 depends on KUNIT 1028 default KUNIT_ALL_TESTS 1029 prompt "Enable s390 specific modules tests" 1030 select S390_MODULES_SANITY_TEST_HELPERS 1031 help 1032 This option enables an s390 specific modules test. This option is 1033 not useful for distributions or general kernels, but only for 1034 kernel developers working on architecture code. 1035 1036 Say N if you are unsure. 1037endmenu 1038