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 PGSTE 36 def_bool y if KVM 37 38config AUDIT_ARCH 39 def_bool y 40 41config NO_IOPORT_MAP 42 def_bool y 43 44config ARCH_SUPPORTS_UPROBES 45 def_bool y 46 47config KASAN_SHADOW_OFFSET 48 hex 49 depends on KASAN 50 default 0x1C000000000000 51 52config CC_HAS_BUILTIN_FFS 53 def_bool !(CC_IS_GCC && GCC_VERSION < 160000) 54 help 55 GCC versions before 16.0.0 generate library calls to ffs() 56 for __builtin_ffs() even when __has_builtin(__builtin_ffs) 57 is true. 58 59config CC_ASM_FLAG_OUTPUT_BROKEN 60 def_bool CC_IS_GCC && GCC_VERSION < 140200 61 help 62 GCC versions before 14.2.0 may die with an internal 63 compiler error in some configurations if flag output 64 operands are used within inline assemblies. 65 66config CC_HAS_ASM_AOR_FORMAT_FLAGS 67 def_bool !(CC_IS_CLANG && CLANG_VERSION < 190100) 68 help 69 Clang versions before 19.1.0 do not support A, 70 O, and R inline assembly format flags. 71 72config S390 73 def_bool y 74 # 75 # Note: keep this list sorted alphabetically 76 # 77 imply IMA_SECURE_AND_OR_TRUSTED_BOOT 78 select ALTERNATE_USER_ADDRESS_SPACE 79 select ARCH_32BIT_USTAT_F_TINODE 80 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 81 select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM 82 select ARCH_ENABLE_MEMORY_HOTREMOVE 83 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2 84 select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE 85 select ARCH_HAS_CPU_FINALIZE_INIT 86 select ARCH_HAS_CURRENT_STACK_POINTER 87 select ARCH_HAS_DEBUG_VIRTUAL 88 select ARCH_HAS_DEBUG_VM_PGTABLE 89 select ARCH_HAS_DEBUG_WX 90 select ARCH_HAS_DEVMEM_IS_ALLOWED 91 select ARCH_HAS_DMA_OPS if PCI 92 select ARCH_HAS_ELF_RANDOMIZE 93 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 94 select ARCH_HAS_FORTIFY_SOURCE 95 select ARCH_HAS_GCOV_PROFILE_ALL 96 select ARCH_HAS_GIGANTIC_PAGE 97 select ARCH_HAS_KCOV 98 select ARCH_HAS_MEMBARRIER_SYNC_CORE 99 select ARCH_HAS_MEM_ENCRYPT 100 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 101 select ARCH_HAS_PREEMPT_LAZY 102 select ARCH_HAS_PTDUMP 103 select ARCH_HAS_PTE_SPECIAL 104 select ARCH_HAS_SCALED_CPUTIME 105 select ARCH_HAS_SET_DIRECT_MAP 106 select ARCH_HAS_SET_MEMORY 107 select ARCH_HAS_STRICT_KERNEL_RWX 108 select ARCH_HAS_STRICT_MODULE_RWX 109 select ARCH_HAS_SYSCALL_WRAPPER 110 select ARCH_HAS_UBSAN 111 select ARCH_HAS_VDSO_TIME_DATA 112 select ARCH_HAVE_NMI_SAFE_CMPXCHG 113 select ARCH_HAVE_TRACE_MMIO_ACCESS 114 select ARCH_INLINE_READ_LOCK 115 select ARCH_INLINE_READ_LOCK_BH 116 select ARCH_INLINE_READ_LOCK_IRQ 117 select ARCH_INLINE_READ_LOCK_IRQSAVE 118 select ARCH_INLINE_READ_TRYLOCK 119 select ARCH_INLINE_READ_UNLOCK 120 select ARCH_INLINE_READ_UNLOCK_BH 121 select ARCH_INLINE_READ_UNLOCK_IRQ 122 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE 123 select ARCH_INLINE_SPIN_LOCK 124 select ARCH_INLINE_SPIN_LOCK_BH 125 select ARCH_INLINE_SPIN_LOCK_IRQ 126 select ARCH_INLINE_SPIN_LOCK_IRQSAVE 127 select ARCH_INLINE_SPIN_TRYLOCK 128 select ARCH_INLINE_SPIN_TRYLOCK_BH 129 select ARCH_INLINE_SPIN_UNLOCK 130 select ARCH_INLINE_SPIN_UNLOCK_BH 131 select ARCH_INLINE_SPIN_UNLOCK_IRQ 132 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE 133 select ARCH_INLINE_WRITE_LOCK 134 select ARCH_INLINE_WRITE_LOCK_BH 135 select ARCH_INLINE_WRITE_LOCK_IRQ 136 select ARCH_INLINE_WRITE_LOCK_IRQSAVE 137 select ARCH_INLINE_WRITE_TRYLOCK 138 select ARCH_INLINE_WRITE_UNLOCK 139 select ARCH_INLINE_WRITE_UNLOCK_BH 140 select ARCH_INLINE_WRITE_UNLOCK_IRQ 141 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE 142 select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 143 select ARCH_MODULE_NEEDS_WEAK_PER_CPU 144 select ARCH_STACKWALK 145 select ARCH_SUPPORTS_ATOMIC_RMW 146 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 147 select ARCH_SUPPORTS_HUGETLBFS 148 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && CC_IS_CLANG 149 select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 150 select ARCH_SUPPORTS_NUMA_BALANCING 151 select ARCH_SUPPORTS_PER_VMA_LOCK 152 select ARCH_USE_BUILTIN_BSWAP 153 select ARCH_USE_CMPXCHG_LOCKREF 154 select ARCH_USE_SYM_ANNOTATIONS 155 select ARCH_WANTS_NO_INSTR 156 select ARCH_WANT_DEFAULT_BPF_JIT 157 select ARCH_WANT_IPC_PARSE_VERSION 158 select ARCH_WANT_IRQS_OFF_ACTIVATE_MM 159 select ARCH_WANT_KERNEL_PMD_MKWRITE 160 select ARCH_WANT_LD_ORPHAN_WARN 161 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP 162 select ARCH_WANTS_THP_SWAP 163 select BUILDTIME_TABLE_SORT 164 select CLONE_BACKWARDS2 165 select DCACHE_WORD_ACCESS if !KMSAN 166 select DYNAMIC_FTRACE if FUNCTION_TRACER 167 select FUNCTION_ALIGNMENT_8B if CC_IS_GCC 168 select FUNCTION_ALIGNMENT_16B if !CC_IS_GCC 169 select GENERIC_ALLOCATOR 170 select GENERIC_CPU_DEVICES 171 select GENERIC_CPU_AUTOPROBE 172 select GENERIC_CPU_VULNERABILITIES 173 select GENERIC_ENTRY 174 select GENERIC_GETTIMEOFDAY 175 select GENERIC_SMP_IDLE_THREAD 176 select GENERIC_TIME_VSYSCALL 177 select GENERIC_IOREMAP if PCI 178 select HAVE_ALIGNED_STRUCT_PAGE 179 select HAVE_ARCH_AUDITSYSCALL 180 select HAVE_ARCH_JUMP_LABEL 181 select HAVE_ARCH_JUMP_LABEL_RELATIVE 182 select HAVE_ARCH_KASAN 183 select HAVE_ARCH_KASAN_VMALLOC 184 select HAVE_ARCH_KCSAN 185 select HAVE_ARCH_KMSAN 186 select HAVE_ARCH_KFENCE 187 select HAVE_ARCH_KSTACK_ERASE 188 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 189 select HAVE_ARCH_SECCOMP_FILTER 190 select HAVE_ARCH_SOFT_DIRTY 191 select HAVE_ARCH_TRACEHOOK 192 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 193 select HAVE_ARCH_VMAP_STACK 194 select HAVE_ASM_MODVERSIONS 195 select HAVE_BUILDTIME_MCOUNT_SORT 196 select HAVE_CMPXCHG_DOUBLE 197 select HAVE_CMPXCHG_LOCAL 198 select HAVE_DEBUG_KMEMLEAK 199 select HAVE_DMA_CONTIGUOUS 200 select HAVE_DYNAMIC_FTRACE 201 select HAVE_DYNAMIC_FTRACE_WITH_ARGS 202 select HAVE_FTRACE_REGS_HAVING_PT_REGS 203 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 204 select HAVE_DYNAMIC_FTRACE_WITH_REGS 205 select HAVE_EBPF_JIT if HAVE_MARCH_Z196_FEATURES 206 select HAVE_EFFICIENT_UNALIGNED_ACCESS 207 select HAVE_GENERIC_TIF_BITS 208 select HAVE_GUP_FAST 209 select HAVE_FENTRY 210 select HAVE_FTRACE_GRAPH_FUNC 211 select HAVE_FUNCTION_ARG_ACCESS_API 212 select HAVE_FUNCTION_ERROR_INJECTION 213 select HAVE_FUNCTION_GRAPH_FREGS 214 select HAVE_FUNCTION_GRAPH_TRACER 215 select HAVE_FUNCTION_TRACER 216 select HAVE_GCC_PLUGINS 217 select HAVE_GENERIC_VDSO 218 select HAVE_IOREMAP_PROT if PCI 219 select HAVE_KERNEL_BZIP2 220 select HAVE_KERNEL_GZIP 221 select HAVE_KERNEL_LZ4 222 select HAVE_KERNEL_LZMA 223 select HAVE_KERNEL_LZO 224 select HAVE_KERNEL_UNCOMPRESSED 225 select HAVE_KERNEL_XZ 226 select HAVE_KERNEL_ZSTD 227 select HAVE_KPROBES 228 select HAVE_KPROBES_ON_FTRACE 229 select HAVE_KRETPROBES 230 select HAVE_LIVEPATCH 231 select HAVE_MEMBLOCK_PHYS_MAP 232 select HAVE_MOD_ARCH_SPECIFIC 233 select HAVE_NMI 234 select HAVE_NOP_MCOUNT 235 select HAVE_PAGE_SIZE_4KB 236 select HAVE_PCI 237 select HAVE_PERF_EVENTS 238 select HAVE_PERF_REGS 239 select HAVE_PERF_USER_STACK_DUMP 240 select HAVE_PREEMPT_DYNAMIC_KEY 241 select HAVE_REGS_AND_STACK_ACCESS_API 242 select HAVE_RELIABLE_STACKTRACE 243 select HAVE_RETHOOK 244 select HAVE_RSEQ 245 select HAVE_SAMPLE_FTRACE_DIRECT 246 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI 247 select HAVE_SETUP_PER_CPU_AREA 248 select HAVE_SOFTIRQ_ON_OWN_STACK 249 select HAVE_SYSCALL_TRACEPOINTS 250 select HAVE_VIRT_CPU_ACCOUNTING 251 select HAVE_VIRT_CPU_ACCOUNTING_IDLE 252 select HOTPLUG_SMT 253 select IOMMU_HELPER if PCI 254 select IOMMU_SUPPORT if PCI 255 select KASAN_VMALLOC if KASAN 256 select LOCK_MM_AND_FIND_VMA 257 select MMU_GATHER_MERGE_VMAS 258 select MMU_GATHER_NO_GATHER 259 select MMU_GATHER_RCU_TABLE_FREE 260 select MODULES_USE_ELF_RELA 261 select NEED_DMA_MAP_STATE if PCI 262 select NEED_PER_CPU_EMBED_FIRST_CHUNK 263 select NEED_PROC_VMCORE_DEVICE_RAM if PROC_VMCORE 264 select NEED_SG_DMA_LENGTH if PCI 265 select OLD_SIGACTION 266 select OLD_SIGSUSPEND3 267 select PCI_DOMAINS if PCI 268 select PCI_MSI if PCI 269 select PCI_MSI_ARCH_FALLBACKS if PCI_MSI 270 select PCI_QUIRKS if PCI 271 select SPARSE_IRQ 272 select SWIOTLB 273 select SYSCTL_EXCEPTION_TRACE 274 select THREAD_INFO_IN_TASK 275 select TRACE_IRQFLAGS_SUPPORT 276 select TTY 277 select USER_STACKTRACE_SUPPORT 278 select VDSO_GETRANDOM 279 select VIRT_CPU_ACCOUNTING 280 select VMAP_STACK 281 select ZONE_DMA 282 # Note: keep the above list sorted alphabetically 283 284config SCHED_OMIT_FRAME_POINTER 285 def_bool y 286 287config PGTABLE_LEVELS 288 int 289 default 5 290 291source "kernel/livepatch/Kconfig" 292 293config ARCH_SUPPORTS_KEXEC 294 def_bool y 295 296config ARCH_SUPPORTS_KEXEC_FILE 297 def_bool y 298 299config ARCH_SUPPORTS_KEXEC_SIG 300 def_bool MODULE_SIG_FORMAT 301 302config ARCH_SUPPORTS_KEXEC_PURGATORY 303 def_bool y 304 305config ARCH_SUPPORTS_CRASH_DUMP 306 def_bool y 307 help 308 Refer to <file:Documentation/arch/s390/zfcpdump.rst> for more details on this. 309 This option also enables s390 zfcpdump. 310 See also <file:Documentation/arch/s390/zfcpdump.rst> 311 312config ARCH_DEFAULT_CRASH_DUMP 313 def_bool y 314 315menu "Processor type and features" 316 317config HAVE_MARCH_Z10_FEATURES 318 def_bool n 319 320config HAVE_MARCH_Z196_FEATURES 321 def_bool n 322 select HAVE_MARCH_Z10_FEATURES 323 324config HAVE_MARCH_ZEC12_FEATURES 325 def_bool n 326 select HAVE_MARCH_Z196_FEATURES 327 328config HAVE_MARCH_Z13_FEATURES 329 def_bool n 330 select HAVE_MARCH_ZEC12_FEATURES 331 332config HAVE_MARCH_Z14_FEATURES 333 def_bool n 334 select HAVE_MARCH_Z13_FEATURES 335 336config HAVE_MARCH_Z15_FEATURES 337 def_bool n 338 select HAVE_MARCH_Z14_FEATURES 339 340config HAVE_MARCH_Z16_FEATURES 341 def_bool n 342 select HAVE_MARCH_Z15_FEATURES 343 344config HAVE_MARCH_Z17_FEATURES 345 def_bool n 346 select HAVE_MARCH_Z16_FEATURES 347 348choice 349 prompt "Processor type" 350 default MARCH_Z196 351 352config MARCH_Z10 353 bool "IBM System z10" 354 select HAVE_MARCH_Z10_FEATURES 355 depends on $(cc-option,-march=z10) 356 help 357 Select this to enable optimizations for IBM System z10 (2097 and 2098 358 series). This is the oldest machine generation currently supported. 359 360config MARCH_Z196 361 bool "IBM zEnterprise 114 and 196" 362 select HAVE_MARCH_Z196_FEATURES 363 depends on $(cc-option,-march=z196) 364 help 365 Select this to enable optimizations for IBM zEnterprise 114 and 196 366 (2818 and 2817 series). The kernel will be slightly faster but will 367 not work on older machines. 368 369config MARCH_ZEC12 370 bool "IBM zBC12 and zEC12" 371 select HAVE_MARCH_ZEC12_FEATURES 372 depends on $(cc-option,-march=zEC12) 373 help 374 Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and 375 2827 series). The kernel will be slightly faster but will not work on 376 older machines. 377 378config MARCH_Z13 379 bool "IBM z13s and z13" 380 select HAVE_MARCH_Z13_FEATURES 381 depends on $(cc-option,-march=z13) 382 help 383 Select this to enable optimizations for IBM z13s and z13 (2965 and 384 2964 series). The kernel will be slightly faster but will not work on 385 older machines. 386 387config MARCH_Z14 388 bool "IBM z14 ZR1 and z14" 389 select HAVE_MARCH_Z14_FEATURES 390 depends on $(cc-option,-march=z14) 391 help 392 Select this to enable optimizations for IBM z14 ZR1 and z14 (3907 393 and 3906 series). The kernel will be slightly faster but will not 394 work on older machines. 395 396config MARCH_Z15 397 bool "IBM z15" 398 select HAVE_MARCH_Z15_FEATURES 399 depends on $(cc-option,-march=z15) 400 help 401 Select this to enable optimizations for IBM z15 (8562 402 and 8561 series). The kernel will be slightly faster but will not 403 work on older machines. 404 405config MARCH_Z16 406 bool "IBM z16" 407 select HAVE_MARCH_Z16_FEATURES 408 depends on $(cc-option,-march=z16) 409 help 410 Select this to enable optimizations for IBM z16 (3931 and 411 3932 series). 412 413config MARCH_Z17 414 bool "IBM z17" 415 select HAVE_MARCH_Z17_FEATURES 416 depends on $(cc-option,-march=z17) 417 help 418 Select this to enable optimizations for IBM z17 (9175 and 419 9176 series). 420 421endchoice 422 423config MARCH_Z10_TUNE 424 def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT 425 426config MARCH_Z196_TUNE 427 def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT 428 429config MARCH_ZEC12_TUNE 430 def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT 431 432config MARCH_Z13_TUNE 433 def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT 434 435config MARCH_Z14_TUNE 436 def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT 437 438config MARCH_Z15_TUNE 439 def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT 440 441config MARCH_Z16_TUNE 442 def_bool TUNE_Z16 || MARCH_Z16 && TUNE_DEFAULT 443 444config MARCH_Z17_TUNE 445 def_bool TUNE_Z17 || MARCH_Z17 && TUNE_DEFAULT 446 447choice 448 prompt "Tune code generation" 449 default TUNE_DEFAULT 450 help 451 Cause the compiler to tune (-mtune) the generated code for a machine. 452 This will make the code run faster on the selected machine but 453 somewhat slower on other machines. 454 This option only changes how the compiler emits instructions, not the 455 selection of instructions itself, so the resulting kernel will run on 456 all other machines. 457 458config TUNE_DEFAULT 459 bool "Default" 460 help 461 Tune the generated code for the target processor for which the kernel 462 will be compiled. 463 464config TUNE_Z10 465 bool "IBM System z10" 466 467config TUNE_Z196 468 bool "IBM zEnterprise 114 and 196" 469 depends on $(cc-option,-mtune=z196) 470 471config TUNE_ZEC12 472 bool "IBM zBC12 and zEC12" 473 depends on $(cc-option,-mtune=zEC12) 474 475config TUNE_Z13 476 bool "IBM z13s and z13" 477 depends on $(cc-option,-mtune=z13) 478 479config TUNE_Z14 480 bool "IBM z14 ZR1 and z14" 481 depends on $(cc-option,-mtune=z14) 482 483config TUNE_Z15 484 bool "IBM z15" 485 depends on $(cc-option,-mtune=z15) 486 487config TUNE_Z16 488 bool "IBM z16" 489 depends on $(cc-option,-mtune=z16) 490 491config TUNE_Z17 492 bool "IBM z17" 493 depends on $(cc-option,-mtune=z17) 494 495endchoice 496 497config 64BIT 498 def_bool y 499 500config COMMAND_LINE_SIZE 501 int "Maximum size of kernel command line" 502 default 4096 503 range 896 1048576 504 help 505 This allows you to specify the maximum length of the kernel command 506 line. 507 508config COMPAT 509 def_bool n 510 prompt "Kernel support for 31 bit emulation" 511 select ARCH_WANT_OLD_COMPAT_IPC 512 select COMPAT_OLD_SIGACTION 513 select HAVE_UID16 514 depends on MULTIUSER 515 depends on !CC_IS_CLANG && !LD_IS_LLD 516 help 517 Select this option if you want to enable your system kernel to 518 handle system-calls from ELF binaries for 31 bit ESA. This option 519 (and some other stuff like libraries and such) is needed for 520 executing 31 bit applications. 521 522 If unsure say N. 523 524config SMP 525 def_bool y 526 527config NR_CPUS 528 int "Maximum number of CPUs (2-512)" 529 range 2 512 530 default "64" 531 help 532 This allows you to specify the maximum number of CPUs which this 533 kernel will support. The maximum supported value is 512 and the 534 minimum value which makes sense is 2. 535 536 This is purely to save memory - each supported CPU adds 537 approximately sixteen kilobytes to the kernel image. 538 539config HOTPLUG_CPU 540 def_bool y 541 542config NUMA 543 bool "NUMA support" 544 depends on SCHED_TOPOLOGY 545 default n 546 help 547 Enable NUMA support 548 549 This option adds NUMA support to the kernel. 550 551config NODES_SHIFT 552 int 553 depends on NUMA 554 default "1" 555 556config SCHED_TOPOLOGY 557 def_bool y 558 prompt "Topology scheduler support" 559 select ARCH_SUPPORTS_SCHED_SMT 560 select ARCH_SUPPORTS_SCHED_MC 561 select SCHED_SMT 562 select SCHED_MC 563 help 564 Topology scheduler support improves the CPU scheduler's decision 565 making when dealing with machines that have multi-threading, 566 multiple cores or multiple books. 567 568config SCHED_TOPOLOGY_VERTICAL 569 def_bool y 570 bool "Use vertical CPU polarization by default" 571 depends on SCHED_TOPOLOGY 572 help 573 Use vertical CPU polarization by default if available. 574 The default CPU polarization is horizontal. 575 576config HIPERDISPATCH_ON 577 def_bool y 578 bool "Use hiperdispatch on vertical polarization by default" 579 depends on SCHED_TOPOLOGY 580 depends on PROC_SYSCTL 581 help 582 Hiperdispatch aims to improve the CPU scheduler's decision 583 making when using vertical polarization by adjusting CPU 584 capacities dynamically. Set this option to use hiperdispatch 585 on vertical polarization by default. This can be overwritten 586 by sysctl's s390.hiperdispatch attribute later on. 587 588source "kernel/Kconfig.hz" 589 590config CERT_STORE 591 bool "Get user certificates via DIAG320" 592 depends on KEYS 593 select CRYPTO_LIB_SHA256 594 help 595 Enable this option if you want to access user-provided secure boot 596 certificates via DIAG 0x320. 597 598 These certificates will be made available via the keyring named 599 'cert_store'. 600 601config KERNEL_NOBP 602 def_bool n 603 prompt "Enable modified branch prediction for the kernel by default" 604 help 605 If this option is selected the kernel will switch to a modified 606 branch prediction mode if the firmware interface is available. 607 The modified branch prediction mode improves the behaviour in 608 regard to speculative execution. 609 610 With the option enabled the kernel parameter "nobp=0" or "nospec" 611 can be used to run the kernel in the normal branch prediction mode. 612 613 With the option disabled the modified branch prediction mode is 614 enabled with the "nobp=1" kernel parameter. 615 616 If unsure, say N. 617 618config EXPOLINE 619 def_bool n 620 depends on $(cc-option,-mindirect-branch=thunk) 621 prompt "Avoid speculative indirect branches in the kernel" 622 help 623 Compile the kernel with the expoline compiler options to guard 624 against kernel-to-user data leaks by avoiding speculative indirect 625 branches. 626 Requires a compiler with -mindirect-branch=thunk support for full 627 protection. The kernel may run slower. 628 629 If unsure, say N. 630 631config EXPOLINE_EXTERN 632 def_bool EXPOLINE && CC_IS_GCC && GCC_VERSION >= 110200 && \ 633 $(success,$(srctree)/arch/s390/tools/gcc-thunk-extern.sh $(CC)) 634 help 635 Generate expolines as external functions if the compiler supports it. 636 This option is required for some tooling like kpatch, if expolines 637 are enabled. The kernel is compiled with 638 -mindirect-branch=thunk-extern, which requires a newer compiler. 639 640choice 641 prompt "Expoline default" 642 depends on EXPOLINE 643 default EXPOLINE_FULL 644 645config EXPOLINE_OFF 646 bool "spectre_v2=off" 647 648config EXPOLINE_AUTO 649 bool "spectre_v2=auto" 650 651config EXPOLINE_FULL 652 bool "spectre_v2=on" 653 654endchoice 655 656config RELOCATABLE 657 def_bool y 658 select ARCH_VMLINUX_NEEDS_RELOCS 659 help 660 This builds a kernel image that retains relocation information 661 so it can be loaded at an arbitrary address. 662 The relocations make the kernel image about 15% larger (compressed 663 10%), but are discarded at runtime. 664 Note: this option exists only for documentation purposes, please do 665 not remove it. 666 667config RANDOMIZE_BASE 668 bool "Randomize the address of the kernel image (KASLR)" 669 default y 670 help 671 In support of Kernel Address Space Layout Randomization (KASLR), 672 this randomizes the address at which the kernel image is loaded, 673 as a security feature that deters exploit attempts relying on 674 knowledge of the location of kernel internals. 675 676config RANDOMIZE_IDENTITY_BASE 677 bool "Randomize the address of the identity mapping base" 678 depends on RANDOMIZE_BASE 679 default DEBUG_VM 680 help 681 The identity mapping base address is pinned to zero by default. 682 Allow randomization of that base to expose otherwise missed 683 notion of physical and virtual addresses of data structures. 684 That does not have any impact on the base address at which the 685 kernel image is loaded. 686 687 If unsure, say N 688 689config KERNEL_IMAGE_BASE 690 hex "Kernel image base address" 691 range 0x100000 0x1FFFFFE0000000 if !KASAN 692 range 0x100000 0x1BFFFFE0000000 if KASAN 693 default 0x3FFE0000000 if !KASAN 694 default 0x7FFFE0000000 if KASAN 695 help 696 This is the address at which the kernel image is loaded in case 697 Kernel Address Space Layout Randomization (KASLR) is disabled. 698 699 In case the Protected virtualization guest support is enabled the 700 Ultravisor imposes a virtual address limit. If the value of this 701 option leads to the kernel image exceeding the Ultravisor limit, 702 this option is ignored and the image is loaded below the limit. 703 704 If the value of this option leads to the kernel image overlapping 705 the virtual memory where other data structures are located, this 706 option is ignored and the image is loaded above the structures. 707 708endmenu 709 710menu "Memory setup" 711 712config ARCH_SPARSEMEM_ENABLE 713 def_bool y 714 select SPARSEMEM_VMEMMAP_ENABLE 715 716config ARCH_SPARSEMEM_DEFAULT 717 def_bool y 718 719config MAX_PHYSMEM_BITS 720 int "Maximum size of supported physical memory in bits (42-53)" 721 range 42 53 722 default "46" 723 help 724 This option specifies the maximum supported size of physical memory 725 in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB). 726 Increasing the number of bits also increases the kernel image size. 727 By default 46 bits (64TB) are supported. 728 729endmenu 730 731menu "I/O subsystem" 732 733config QDIO 734 def_tristate y 735 prompt "QDIO support" 736 help 737 This driver provides the Queued Direct I/O base support for 738 IBM System z. 739 740 To compile this driver as a module, choose M here: the 741 module will be called qdio. 742 743 If unsure, say Y. 744 745if PCI 746 747config PCI_NR_FUNCTIONS 748 int "Maximum number of PCI functions (1-4096)" 749 range 1 4096 750 default "512" 751 help 752 This allows you to specify the maximum number of PCI functions which 753 this kernel will support. 754 755endif # PCI 756 757config HAS_IOMEM 758 def_bool PCI 759 760config CHSC_SCH 761 def_tristate m 762 prompt "Support for CHSC subchannels" 763 help 764 This driver allows usage of CHSC subchannels. A CHSC subchannel 765 is usually present on LPAR only. 766 The driver creates a device /dev/chsc, which may be used to 767 obtain I/O configuration information about the machine and 768 to issue asynchronous chsc commands (DANGEROUS). 769 You will usually only want to use this interface on a special 770 LPAR designated for system management. 771 772 To compile this driver as a module, choose M here: the 773 module will be called chsc_sch. 774 775 If unsure, say N. 776 777config SCM_BUS 778 def_bool y 779 prompt "SCM bus driver" 780 help 781 Bus driver for Storage Class Memory. 782 783config EADM_SCH 784 def_tristate m 785 prompt "Support for EADM subchannels" 786 depends on SCM_BUS 787 help 788 This driver allows usage of EADM subchannels. EADM subchannels act 789 as a communication vehicle for SCM increments. 790 791 To compile this driver as a module, choose M here: the 792 module will be called eadm_sch. 793 794config AP 795 def_tristate y 796 prompt "Support for Adjunct Processors (ap)" 797 help 798 This driver allows usage to Adjunct Processor (AP) devices via 799 the ap bus, cards and queues. Supported Adjunct Processors are 800 the CryptoExpress Cards (CEX). 801 802 To compile this driver as a module, choose M here: the 803 module will be called ap. 804 805 If unsure, say Y (default). 806 807config AP_DEBUG 808 def_bool n 809 prompt "Enable debug features for Adjunct Processor (ap) devices" 810 depends on AP 811 help 812 Say 'Y' here to enable some additional debug features for Adjunct 813 Processor (ap) devices. 814 815 There will be some more sysfs attributes displayed for ap queues. 816 817 Do not enable on production level kernel build. 818 819 If unsure, say N. 820 821config VFIO_CCW 822 def_tristate n 823 prompt "Support for VFIO-CCW subchannels" 824 depends on VFIO 825 select VFIO_MDEV 826 help 827 This driver allows usage of I/O subchannels via VFIO-CCW. 828 829 To compile this driver as a module, choose M here: the 830 module will be called vfio_ccw. 831 832config VFIO_AP 833 def_tristate n 834 prompt "VFIO support for AP devices" 835 depends on KVM 836 depends on VFIO 837 depends on AP 838 select VFIO_MDEV 839 help 840 This driver grants access to Adjunct Processor (AP) devices 841 via the VFIO mediated device interface. 842 843 To compile this driver as a module, choose M here: the module 844 will be called vfio_ap. 845 846endmenu 847 848config CCW 849 def_bool y 850 851config HAVE_PNETID 852 tristate 853 default (SMC || CCWGROUP) 854 855menu "Virtualization" 856 857config PFAULT 858 def_bool y 859 prompt "Pseudo page fault support" 860 help 861 Select this option, if you want to use PFAULT pseudo page fault 862 handling under VM. If running native or in LPAR, this option 863 has no effect. If your VM does not support PFAULT, PAGEEX 864 pseudo page fault handling will be used. 865 Note that VM 4.2 supports PFAULT but has a bug in its 866 implementation that causes some problems. 867 Everybody who wants to run Linux under VM != VM4.2 should select 868 this option. 869 870config CMM 871 def_tristate n 872 prompt "Cooperative memory management" 873 help 874 Select this option, if you want to enable the kernel interface 875 to reduce the memory size of the system. This is accomplished 876 by allocating pages of memory and put them "on hold". This only 877 makes sense for a system running under VM where the unused pages 878 will be reused by VM for other guest systems. The interface 879 allows an external monitor to balance memory of many systems. 880 Everybody who wants to run Linux under VM should select this 881 option. 882 883config CMM_IUCV 884 def_bool y 885 prompt "IUCV special message interface to cooperative memory management" 886 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV) 887 help 888 Select this option to enable the special message interface to 889 the cooperative memory management. 890 891config APPLDATA_BASE 892 def_bool n 893 prompt "Linux - VM Monitor Stream, base infrastructure" 894 depends on PROC_SYSCTL 895 help 896 This provides a kernel interface for creating and updating z/VM APPLDATA 897 monitor records. The monitor records are updated at certain time 898 intervals, once the timer is started. 899 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer, 900 i.e. enables or disables monitoring on the Linux side. 901 A custom interval value (in seconds) can be written to 902 /proc/appldata/interval. 903 904 Defaults are 60 seconds interval and timer off. 905 The /proc entries can also be read from, showing the current settings. 906 907config APPLDATA_MEM 908 def_tristate m 909 prompt "Monitor memory management statistics" 910 depends on APPLDATA_BASE && VM_EVENT_COUNTERS 911 help 912 This provides memory management related data to the Linux - VM Monitor 913 Stream, like paging/swapping rate, memory utilisation, etc. 914 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM 915 APPLDATA monitor record, i.e. enables or disables monitoring this record 916 on the z/VM side. 917 918 Default is disabled. 919 The /proc entry can also be read from, showing the current settings. 920 921 This can also be compiled as a module, which will be called 922 appldata_mem.o. 923 924config APPLDATA_OS 925 def_tristate m 926 prompt "Monitor OS statistics" 927 depends on APPLDATA_BASE 928 help 929 This provides OS related data to the Linux - VM Monitor Stream, like 930 CPU utilisation, etc. 931 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM 932 APPLDATA monitor record, i.e. enables or disables monitoring this record 933 on the z/VM side. 934 935 Default is disabled. 936 This can also be compiled as a module, which will be called 937 appldata_os.o. 938 939config APPLDATA_NET_SUM 940 def_tristate m 941 prompt "Monitor overall network statistics" 942 depends on APPLDATA_BASE && NET 943 help 944 This provides network related data to the Linux - VM Monitor Stream, 945 currently there is only a total sum of network I/O statistics, no 946 per-interface data. 947 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM 948 APPLDATA monitor record, i.e. enables or disables monitoring this record 949 on the z/VM side. 950 951 Default is disabled. 952 This can also be compiled as a module, which will be called 953 appldata_net_sum.o. 954 955config S390_HYPFS 956 def_bool y 957 prompt "s390 hypervisor information" 958 help 959 This provides several binary files at (debugfs)/s390_hypfs/ to 960 provide accounting information in an s390 hypervisor environment. 961 962config S390_HYPFS_FS 963 def_bool n 964 prompt "s390 hypervisor file system support" 965 select SYS_HYPERVISOR 966 depends on S390_HYPFS 967 help 968 This is a virtual file system intended to provide accounting 969 information in an s390 hypervisor environment. This file system 970 is deprecated and should not be used. 971 972 Say N if you are unsure. 973 974source "arch/s390/kvm/Kconfig" 975 976config S390_GUEST 977 def_bool y 978 prompt "s390 support for virtio devices" 979 select TTY 980 select VIRTUALIZATION 981 select VIRTIO 982 help 983 Enabling this option adds support for virtio based paravirtual device 984 drivers on s390. 985 986 Select this option if you want to run the kernel as a guest under 987 the KVM hypervisor. 988 989endmenu 990 991config S390_MODULES_SANITY_TEST_HELPERS 992 def_bool n 993 994menu "Selftests" 995 996config S390_UNWIND_SELFTEST 997 def_tristate n 998 depends on KUNIT 999 default KUNIT_ALL_TESTS 1000 prompt "Test unwind functions" 1001 help 1002 This option enables s390 specific stack unwinder testing kernel 1003 module. This option is not useful for distributions or general 1004 kernels, but only for kernel developers working on architecture code. 1005 1006 Say N if you are unsure. 1007 1008config S390_KPROBES_SANITY_TEST 1009 def_tristate n 1010 prompt "Enable s390 specific kprobes tests" 1011 depends on KPROBES 1012 depends on KUNIT 1013 help 1014 This option enables an s390 specific kprobes test module. This option 1015 is not useful for distributions or general kernels, but only for kernel 1016 developers working on architecture code. 1017 1018 Say N if you are unsure. 1019 1020config S390_MODULES_SANITY_TEST 1021 def_tristate n 1022 depends on KUNIT 1023 default KUNIT_ALL_TESTS 1024 prompt "Enable s390 specific modules tests" 1025 select S390_MODULES_SANITY_TEST_HELPERS 1026 help 1027 This option enables an s390 specific modules test. This option is 1028 not useful for distributions or general kernels, but only for 1029 kernel developers working on architecture code. 1030 1031 Say N if you are unsure. 1032endmenu 1033