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