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_VDSO_DATA_STORE 178 select GENERIC_VDSO_TIME_NS 179 select GENERIC_IOREMAP if PCI 180 select HAVE_ALIGNED_STRUCT_PAGE 181 select HAVE_ARCH_AUDITSYSCALL 182 select HAVE_ARCH_JUMP_LABEL 183 select HAVE_ARCH_JUMP_LABEL_RELATIVE 184 select HAVE_ARCH_KASAN 185 select HAVE_ARCH_KASAN_VMALLOC 186 select HAVE_ARCH_KCSAN 187 select HAVE_ARCH_KMSAN 188 select HAVE_ARCH_KFENCE 189 select HAVE_ARCH_KSTACK_ERASE 190 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 191 select HAVE_ARCH_SECCOMP_FILTER 192 select HAVE_ARCH_SOFT_DIRTY 193 select HAVE_ARCH_TRACEHOOK 194 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 195 select HAVE_ARCH_VMAP_STACK 196 select HAVE_ASM_MODVERSIONS 197 select HAVE_BUILDTIME_MCOUNT_SORT 198 select HAVE_CMPXCHG_DOUBLE 199 select HAVE_CMPXCHG_LOCAL 200 select HAVE_DEBUG_KMEMLEAK 201 select HAVE_DMA_CONTIGUOUS 202 select HAVE_DYNAMIC_FTRACE 203 select HAVE_DYNAMIC_FTRACE_WITH_ARGS 204 select HAVE_FTRACE_REGS_HAVING_PT_REGS 205 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 206 select HAVE_DYNAMIC_FTRACE_WITH_REGS 207 select HAVE_EBPF_JIT if HAVE_MARCH_Z196_FEATURES 208 select HAVE_EFFICIENT_UNALIGNED_ACCESS 209 select HAVE_GENERIC_TIF_BITS 210 select HAVE_GUP_FAST 211 select HAVE_FENTRY 212 select HAVE_FTRACE_GRAPH_FUNC 213 select HAVE_FUNCTION_ARG_ACCESS_API 214 select HAVE_FUNCTION_ERROR_INJECTION 215 select HAVE_FUNCTION_GRAPH_FREGS 216 select HAVE_FUNCTION_GRAPH_TRACER 217 select HAVE_FUNCTION_TRACER 218 select HAVE_GCC_PLUGINS 219 select HAVE_GENERIC_VDSO 220 select HAVE_IOREMAP_PROT if PCI 221 select HAVE_KERNEL_BZIP2 222 select HAVE_KERNEL_GZIP 223 select HAVE_KERNEL_LZ4 224 select HAVE_KERNEL_LZMA 225 select HAVE_KERNEL_LZO 226 select HAVE_KERNEL_UNCOMPRESSED 227 select HAVE_KERNEL_XZ 228 select HAVE_KERNEL_ZSTD 229 select HAVE_KPROBES 230 select HAVE_KPROBES_ON_FTRACE 231 select HAVE_KRETPROBES 232 select HAVE_LIVEPATCH 233 select HAVE_MEMBLOCK_PHYS_MAP 234 select HAVE_MOD_ARCH_SPECIFIC 235 select HAVE_NMI 236 select HAVE_NOP_MCOUNT 237 select HAVE_PAGE_SIZE_4KB 238 select HAVE_PCI 239 select HAVE_PERF_EVENTS 240 select HAVE_PERF_REGS 241 select HAVE_PERF_USER_STACK_DUMP 242 select HAVE_PREEMPT_DYNAMIC_KEY 243 select HAVE_REGS_AND_STACK_ACCESS_API 244 select HAVE_RELIABLE_STACKTRACE 245 select HAVE_RETHOOK 246 select HAVE_RSEQ 247 select HAVE_SAMPLE_FTRACE_DIRECT 248 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI 249 select HAVE_SETUP_PER_CPU_AREA 250 select HAVE_SOFTIRQ_ON_OWN_STACK 251 select HAVE_SYSCALL_TRACEPOINTS 252 select HAVE_VIRT_CPU_ACCOUNTING 253 select HAVE_VIRT_CPU_ACCOUNTING_IDLE 254 select HOTPLUG_SMT 255 select IOMMU_HELPER if PCI 256 select IOMMU_SUPPORT if PCI 257 select KASAN_VMALLOC if KASAN 258 select LOCK_MM_AND_FIND_VMA 259 select MMU_GATHER_MERGE_VMAS 260 select MMU_GATHER_NO_GATHER 261 select MMU_GATHER_RCU_TABLE_FREE 262 select MODULES_USE_ELF_RELA 263 select NEED_DMA_MAP_STATE if PCI 264 select NEED_PER_CPU_EMBED_FIRST_CHUNK 265 select NEED_PROC_VMCORE_DEVICE_RAM if PROC_VMCORE 266 select NEED_SG_DMA_LENGTH if PCI 267 select OLD_SIGACTION 268 select OLD_SIGSUSPEND3 269 select PCI_DOMAINS if PCI 270 select PCI_MSI if PCI 271 select PCI_MSI_ARCH_FALLBACKS if PCI_MSI 272 select PCI_QUIRKS if PCI 273 select SPARSE_IRQ 274 select SWIOTLB 275 select SYSCTL_EXCEPTION_TRACE 276 select THREAD_INFO_IN_TASK 277 select TRACE_IRQFLAGS_SUPPORT 278 select TTY 279 select USER_STACKTRACE_SUPPORT 280 select VDSO_GETRANDOM 281 select VIRT_CPU_ACCOUNTING 282 select VMAP_STACK 283 select ZONE_DMA 284 # Note: keep the above list sorted alphabetically 285 286config SCHED_OMIT_FRAME_POINTER 287 def_bool y 288 289config PGTABLE_LEVELS 290 int 291 default 5 292 293source "kernel/livepatch/Kconfig" 294 295config ARCH_SUPPORTS_KEXEC 296 def_bool y 297 298config ARCH_SUPPORTS_KEXEC_FILE 299 def_bool y 300 301config ARCH_SUPPORTS_KEXEC_SIG 302 def_bool MODULE_SIG_FORMAT 303 304config ARCH_SUPPORTS_KEXEC_PURGATORY 305 def_bool y 306 307config ARCH_SUPPORTS_CRASH_DUMP 308 def_bool y 309 help 310 Refer to <file:Documentation/arch/s390/zfcpdump.rst> for more details on this. 311 This option also enables s390 zfcpdump. 312 See also <file:Documentation/arch/s390/zfcpdump.rst> 313 314config ARCH_DEFAULT_CRASH_DUMP 315 def_bool y 316 317menu "Processor type and features" 318 319config HAVE_MARCH_Z10_FEATURES 320 def_bool n 321 322config HAVE_MARCH_Z196_FEATURES 323 def_bool n 324 select HAVE_MARCH_Z10_FEATURES 325 326config HAVE_MARCH_ZEC12_FEATURES 327 def_bool n 328 select HAVE_MARCH_Z196_FEATURES 329 330config HAVE_MARCH_Z13_FEATURES 331 def_bool n 332 select HAVE_MARCH_ZEC12_FEATURES 333 334config HAVE_MARCH_Z14_FEATURES 335 def_bool n 336 select HAVE_MARCH_Z13_FEATURES 337 338config HAVE_MARCH_Z15_FEATURES 339 def_bool n 340 select HAVE_MARCH_Z14_FEATURES 341 342config HAVE_MARCH_Z16_FEATURES 343 def_bool n 344 select HAVE_MARCH_Z15_FEATURES 345 346config HAVE_MARCH_Z17_FEATURES 347 def_bool n 348 select HAVE_MARCH_Z16_FEATURES 349 350choice 351 prompt "Processor type" 352 default MARCH_Z196 353 354config MARCH_Z10 355 bool "IBM System z10" 356 select HAVE_MARCH_Z10_FEATURES 357 depends on $(cc-option,-march=z10) 358 help 359 Select this to enable optimizations for IBM System z10 (2097 and 2098 360 series). This is the oldest machine generation currently supported. 361 362config MARCH_Z196 363 bool "IBM zEnterprise 114 and 196" 364 select HAVE_MARCH_Z196_FEATURES 365 depends on $(cc-option,-march=z196) 366 help 367 Select this to enable optimizations for IBM zEnterprise 114 and 196 368 (2818 and 2817 series). The kernel will be slightly faster but will 369 not work on older machines. 370 371config MARCH_ZEC12 372 bool "IBM zBC12 and zEC12" 373 select HAVE_MARCH_ZEC12_FEATURES 374 depends on $(cc-option,-march=zEC12) 375 help 376 Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and 377 2827 series). The kernel will be slightly faster but will not work on 378 older machines. 379 380config MARCH_Z13 381 bool "IBM z13s and z13" 382 select HAVE_MARCH_Z13_FEATURES 383 depends on $(cc-option,-march=z13) 384 help 385 Select this to enable optimizations for IBM z13s and z13 (2965 and 386 2964 series). The kernel will be slightly faster but will not work on 387 older machines. 388 389config MARCH_Z14 390 bool "IBM z14 ZR1 and z14" 391 select HAVE_MARCH_Z14_FEATURES 392 depends on $(cc-option,-march=z14) 393 help 394 Select this to enable optimizations for IBM z14 ZR1 and z14 (3907 395 and 3906 series). The kernel will be slightly faster but will not 396 work on older machines. 397 398config MARCH_Z15 399 bool "IBM z15" 400 select HAVE_MARCH_Z15_FEATURES 401 depends on $(cc-option,-march=z15) 402 help 403 Select this to enable optimizations for IBM z15 (8562 404 and 8561 series). The kernel will be slightly faster but will not 405 work on older machines. 406 407config MARCH_Z16 408 bool "IBM z16" 409 select HAVE_MARCH_Z16_FEATURES 410 depends on $(cc-option,-march=z16) 411 help 412 Select this to enable optimizations for IBM z16 (3931 and 413 3932 series). 414 415config MARCH_Z17 416 bool "IBM z17" 417 select HAVE_MARCH_Z17_FEATURES 418 depends on $(cc-option,-march=z17) 419 help 420 Select this to enable optimizations for IBM z17 (9175 and 421 9176 series). 422 423endchoice 424 425config MARCH_Z10_TUNE 426 def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT 427 428config MARCH_Z196_TUNE 429 def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT 430 431config MARCH_ZEC12_TUNE 432 def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT 433 434config MARCH_Z13_TUNE 435 def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT 436 437config MARCH_Z14_TUNE 438 def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT 439 440config MARCH_Z15_TUNE 441 def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT 442 443config MARCH_Z16_TUNE 444 def_bool TUNE_Z16 || MARCH_Z16 && TUNE_DEFAULT 445 446config MARCH_Z17_TUNE 447 def_bool TUNE_Z17 || MARCH_Z17 && TUNE_DEFAULT 448 449choice 450 prompt "Tune code generation" 451 default TUNE_DEFAULT 452 help 453 Cause the compiler to tune (-mtune) the generated code for a machine. 454 This will make the code run faster on the selected machine but 455 somewhat slower on other machines. 456 This option only changes how the compiler emits instructions, not the 457 selection of instructions itself, so the resulting kernel will run on 458 all other machines. 459 460config TUNE_DEFAULT 461 bool "Default" 462 help 463 Tune the generated code for the target processor for which the kernel 464 will be compiled. 465 466config TUNE_Z10 467 bool "IBM System z10" 468 469config TUNE_Z196 470 bool "IBM zEnterprise 114 and 196" 471 depends on $(cc-option,-mtune=z196) 472 473config TUNE_ZEC12 474 bool "IBM zBC12 and zEC12" 475 depends on $(cc-option,-mtune=zEC12) 476 477config TUNE_Z13 478 bool "IBM z13s and z13" 479 depends on $(cc-option,-mtune=z13) 480 481config TUNE_Z14 482 bool "IBM z14 ZR1 and z14" 483 depends on $(cc-option,-mtune=z14) 484 485config TUNE_Z15 486 bool "IBM z15" 487 depends on $(cc-option,-mtune=z15) 488 489config TUNE_Z16 490 bool "IBM z16" 491 depends on $(cc-option,-mtune=z16) 492 493config TUNE_Z17 494 bool "IBM z17" 495 depends on $(cc-option,-mtune=z17) 496 497endchoice 498 499config 64BIT 500 def_bool y 501 502config COMMAND_LINE_SIZE 503 int "Maximum size of kernel command line" 504 default 4096 505 range 896 1048576 506 help 507 This allows you to specify the maximum length of the kernel command 508 line. 509 510config COMPAT 511 def_bool n 512 prompt "Kernel support for 31 bit emulation" 513 select ARCH_WANT_OLD_COMPAT_IPC 514 select COMPAT_OLD_SIGACTION 515 select HAVE_UID16 516 depends on MULTIUSER 517 depends on !CC_IS_CLANG && !LD_IS_LLD 518 help 519 Select this option if you want to enable your system kernel to 520 handle system-calls from ELF binaries for 31 bit ESA. This option 521 (and some other stuff like libraries and such) is needed for 522 executing 31 bit applications. 523 524 If unsure say N. 525 526config SMP 527 def_bool y 528 529config NR_CPUS 530 int "Maximum number of CPUs (2-512)" 531 range 2 512 532 default "64" 533 help 534 This allows you to specify the maximum number of CPUs which this 535 kernel will support. The maximum supported value is 512 and the 536 minimum value which makes sense is 2. 537 538 This is purely to save memory - each supported CPU adds 539 approximately sixteen kilobytes to the kernel image. 540 541config HOTPLUG_CPU 542 def_bool y 543 544config NUMA 545 bool "NUMA support" 546 depends on SCHED_TOPOLOGY 547 default n 548 help 549 Enable NUMA support 550 551 This option adds NUMA support to the kernel. 552 553config NODES_SHIFT 554 int 555 depends on NUMA 556 default "1" 557 558config SCHED_TOPOLOGY 559 def_bool y 560 prompt "Topology scheduler support" 561 select ARCH_SUPPORTS_SCHED_SMT 562 select ARCH_SUPPORTS_SCHED_MC 563 select SCHED_SMT 564 select SCHED_MC 565 help 566 Topology scheduler support improves the CPU scheduler's decision 567 making when dealing with machines that have multi-threading, 568 multiple cores or multiple books. 569 570config SCHED_TOPOLOGY_VERTICAL 571 def_bool y 572 bool "Use vertical CPU polarization by default" 573 depends on SCHED_TOPOLOGY 574 help 575 Use vertical CPU polarization by default if available. 576 The default CPU polarization is horizontal. 577 578config HIPERDISPATCH_ON 579 def_bool y 580 bool "Use hiperdispatch on vertical polarization by default" 581 depends on SCHED_TOPOLOGY 582 depends on PROC_SYSCTL 583 help 584 Hiperdispatch aims to improve the CPU scheduler's decision 585 making when using vertical polarization by adjusting CPU 586 capacities dynamically. Set this option to use hiperdispatch 587 on vertical polarization by default. This can be overwritten 588 by sysctl's s390.hiperdispatch attribute later on. 589 590source "kernel/Kconfig.hz" 591 592config CERT_STORE 593 bool "Get user certificates via DIAG320" 594 depends on KEYS 595 select CRYPTO_LIB_SHA256 596 help 597 Enable this option if you want to access user-provided secure boot 598 certificates via DIAG 0x320. 599 600 These certificates will be made available via the keyring named 601 'cert_store'. 602 603config KERNEL_NOBP 604 def_bool n 605 prompt "Enable modified branch prediction for the kernel by default" 606 help 607 If this option is selected the kernel will switch to a modified 608 branch prediction mode if the firmware interface is available. 609 The modified branch prediction mode improves the behaviour in 610 regard to speculative execution. 611 612 With the option enabled the kernel parameter "nobp=0" or "nospec" 613 can be used to run the kernel in the normal branch prediction mode. 614 615 With the option disabled the modified branch prediction mode is 616 enabled with the "nobp=1" kernel parameter. 617 618 If unsure, say N. 619 620config EXPOLINE 621 def_bool n 622 depends on $(cc-option,-mindirect-branch=thunk) 623 prompt "Avoid speculative indirect branches in the kernel" 624 help 625 Compile the kernel with the expoline compiler options to guard 626 against kernel-to-user data leaks by avoiding speculative indirect 627 branches. 628 Requires a compiler with -mindirect-branch=thunk support for full 629 protection. The kernel may run slower. 630 631 If unsure, say N. 632 633config EXPOLINE_EXTERN 634 def_bool EXPOLINE && CC_IS_GCC && GCC_VERSION >= 110200 && \ 635 $(success,$(srctree)/arch/s390/tools/gcc-thunk-extern.sh $(CC)) 636 help 637 Generate expolines as external functions if the compiler supports it. 638 This option is required for some tooling like kpatch, if expolines 639 are enabled. The kernel is compiled with 640 -mindirect-branch=thunk-extern, which requires a newer compiler. 641 642choice 643 prompt "Expoline default" 644 depends on EXPOLINE 645 default EXPOLINE_FULL 646 647config EXPOLINE_OFF 648 bool "spectre_v2=off" 649 650config EXPOLINE_AUTO 651 bool "spectre_v2=auto" 652 653config EXPOLINE_FULL 654 bool "spectre_v2=on" 655 656endchoice 657 658config RELOCATABLE 659 def_bool y 660 select ARCH_VMLINUX_NEEDS_RELOCS 661 help 662 This builds a kernel image that retains relocation information 663 so it can be loaded at an arbitrary address. 664 The relocations make the kernel image about 15% larger (compressed 665 10%), but are discarded at runtime. 666 Note: this option exists only for documentation purposes, please do 667 not remove it. 668 669config RANDOMIZE_BASE 670 bool "Randomize the address of the kernel image (KASLR)" 671 default y 672 help 673 In support of Kernel Address Space Layout Randomization (KASLR), 674 this randomizes the address at which the kernel image is loaded, 675 as a security feature that deters exploit attempts relying on 676 knowledge of the location of kernel internals. 677 678config RANDOMIZE_IDENTITY_BASE 679 bool "Randomize the address of the identity mapping base" 680 depends on RANDOMIZE_BASE 681 default DEBUG_VM 682 help 683 The identity mapping base address is pinned to zero by default. 684 Allow randomization of that base to expose otherwise missed 685 notion of physical and virtual addresses of data structures. 686 That does not have any impact on the base address at which the 687 kernel image is loaded. 688 689 If unsure, say N 690 691config KERNEL_IMAGE_BASE 692 hex "Kernel image base address" 693 range 0x100000 0x1FFFFFE0000000 if !KASAN 694 range 0x100000 0x1BFFFFE0000000 if KASAN 695 default 0x3FFE0000000 if !KASAN 696 default 0x7FFFE0000000 if KASAN 697 help 698 This is the address at which the kernel image is loaded in case 699 Kernel Address Space Layout Randomization (KASLR) is disabled. 700 701 In case the Protected virtualization guest support is enabled the 702 Ultravisor imposes a virtual address limit. If the value of this 703 option leads to the kernel image exceeding the Ultravisor limit, 704 this option is ignored and the image is loaded below the limit. 705 706 If the value of this option leads to the kernel image overlapping 707 the virtual memory where other data structures are located, this 708 option is ignored and the image is loaded above the structures. 709 710endmenu 711 712menu "Memory setup" 713 714config ARCH_SPARSEMEM_ENABLE 715 def_bool y 716 select SPARSEMEM_VMEMMAP_ENABLE 717 select SPARSEMEM_VMEMMAP 718 719config ARCH_SPARSEMEM_DEFAULT 720 def_bool y 721 722config MAX_PHYSMEM_BITS 723 int "Maximum size of supported physical memory in bits (42-53)" 724 range 42 53 725 default "46" 726 help 727 This option specifies the maximum supported size of physical memory 728 in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB). 729 Increasing the number of bits also increases the kernel image size. 730 By default 46 bits (64TB) are supported. 731 732endmenu 733 734menu "I/O subsystem" 735 736config QDIO 737 def_tristate y 738 prompt "QDIO support" 739 help 740 This driver provides the Queued Direct I/O base support for 741 IBM System z. 742 743 To compile this driver as a module, choose M here: the 744 module will be called qdio. 745 746 If unsure, say Y. 747 748if PCI 749 750config PCI_NR_FUNCTIONS 751 int "Maximum number of PCI functions (1-4096)" 752 range 1 4096 753 default "512" 754 help 755 This allows you to specify the maximum number of PCI functions which 756 this kernel will support. 757 758endif # PCI 759 760config HAS_IOMEM 761 def_bool PCI 762 763config CHSC_SCH 764 def_tristate m 765 prompt "Support for CHSC subchannels" 766 help 767 This driver allows usage of CHSC subchannels. A CHSC subchannel 768 is usually present on LPAR only. 769 The driver creates a device /dev/chsc, which may be used to 770 obtain I/O configuration information about the machine and 771 to issue asynchronous chsc commands (DANGEROUS). 772 You will usually only want to use this interface on a special 773 LPAR designated for system management. 774 775 To compile this driver as a module, choose M here: the 776 module will be called chsc_sch. 777 778 If unsure, say N. 779 780config SCM_BUS 781 def_bool y 782 prompt "SCM bus driver" 783 help 784 Bus driver for Storage Class Memory. 785 786config EADM_SCH 787 def_tristate m 788 prompt "Support for EADM subchannels" 789 depends on SCM_BUS 790 help 791 This driver allows usage of EADM subchannels. EADM subchannels act 792 as a communication vehicle for SCM increments. 793 794 To compile this driver as a module, choose M here: the 795 module will be called eadm_sch. 796 797config AP 798 def_tristate y 799 prompt "Support for Adjunct Processors (ap)" 800 help 801 This driver allows usage to Adjunct Processor (AP) devices via 802 the ap bus, cards and queues. Supported Adjunct Processors are 803 the CryptoExpress Cards (CEX). 804 805 To compile this driver as a module, choose M here: the 806 module will be called ap. 807 808 If unsure, say Y (default). 809 810config AP_DEBUG 811 def_bool n 812 prompt "Enable debug features for Adjunct Processor (ap) devices" 813 depends on AP 814 help 815 Say 'Y' here to enable some additional debug features for Adjunct 816 Processor (ap) devices. 817 818 There will be some more sysfs attributes displayed for ap queues. 819 820 Do not enable on production level kernel build. 821 822 If unsure, say N. 823 824config VFIO_CCW 825 def_tristate n 826 prompt "Support for VFIO-CCW subchannels" 827 depends on VFIO 828 select VFIO_MDEV 829 help 830 This driver allows usage of I/O subchannels via VFIO-CCW. 831 832 To compile this driver as a module, choose M here: the 833 module will be called vfio_ccw. 834 835config VFIO_AP 836 def_tristate n 837 prompt "VFIO support for AP devices" 838 depends on KVM 839 depends on VFIO 840 depends on AP 841 select VFIO_MDEV 842 help 843 This driver grants access to Adjunct Processor (AP) devices 844 via the VFIO mediated device interface. 845 846 To compile this driver as a module, choose M here: the module 847 will be called vfio_ap. 848 849endmenu 850 851config CCW 852 def_bool y 853 854config HAVE_PNETID 855 tristate 856 default (SMC || CCWGROUP) 857 858menu "Virtualization" 859 860config PFAULT 861 def_bool y 862 prompt "Pseudo page fault support" 863 help 864 Select this option, if you want to use PFAULT pseudo page fault 865 handling under VM. If running native or in LPAR, this option 866 has no effect. If your VM does not support PFAULT, PAGEEX 867 pseudo page fault handling will be used. 868 Note that VM 4.2 supports PFAULT but has a bug in its 869 implementation that causes some problems. 870 Everybody who wants to run Linux under VM != VM4.2 should select 871 this option. 872 873config CMM 874 def_tristate n 875 prompt "Cooperative memory management" 876 help 877 Select this option, if you want to enable the kernel interface 878 to reduce the memory size of the system. This is accomplished 879 by allocating pages of memory and put them "on hold". This only 880 makes sense for a system running under VM where the unused pages 881 will be reused by VM for other guest systems. The interface 882 allows an external monitor to balance memory of many systems. 883 Everybody who wants to run Linux under VM should select this 884 option. 885 886config CMM_IUCV 887 def_bool y 888 prompt "IUCV special message interface to cooperative memory management" 889 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV) 890 help 891 Select this option to enable the special message interface to 892 the cooperative memory management. 893 894config APPLDATA_BASE 895 def_bool n 896 prompt "Linux - VM Monitor Stream, base infrastructure" 897 depends on PROC_SYSCTL 898 help 899 This provides a kernel interface for creating and updating z/VM APPLDATA 900 monitor records. The monitor records are updated at certain time 901 intervals, once the timer is started. 902 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer, 903 i.e. enables or disables monitoring on the Linux side. 904 A custom interval value (in seconds) can be written to 905 /proc/appldata/interval. 906 907 Defaults are 60 seconds interval and timer off. 908 The /proc entries can also be read from, showing the current settings. 909 910config APPLDATA_MEM 911 def_tristate m 912 prompt "Monitor memory management statistics" 913 depends on APPLDATA_BASE && VM_EVENT_COUNTERS 914 help 915 This provides memory management related data to the Linux - VM Monitor 916 Stream, like paging/swapping rate, memory utilisation, etc. 917 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM 918 APPLDATA monitor record, i.e. enables or disables monitoring this record 919 on the z/VM side. 920 921 Default is disabled. 922 The /proc entry can also be read from, showing the current settings. 923 924 This can also be compiled as a module, which will be called 925 appldata_mem.o. 926 927config APPLDATA_OS 928 def_tristate m 929 prompt "Monitor OS statistics" 930 depends on APPLDATA_BASE 931 help 932 This provides OS related data to the Linux - VM Monitor Stream, like 933 CPU utilisation, etc. 934 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM 935 APPLDATA monitor record, i.e. enables or disables monitoring this record 936 on the z/VM side. 937 938 Default is disabled. 939 This can also be compiled as a module, which will be called 940 appldata_os.o. 941 942config APPLDATA_NET_SUM 943 def_tristate m 944 prompt "Monitor overall network statistics" 945 depends on APPLDATA_BASE && NET 946 help 947 This provides network related data to the Linux - VM Monitor Stream, 948 currently there is only a total sum of network I/O statistics, no 949 per-interface data. 950 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM 951 APPLDATA monitor record, i.e. enables or disables monitoring this record 952 on the z/VM side. 953 954 Default is disabled. 955 This can also be compiled as a module, which will be called 956 appldata_net_sum.o. 957 958config S390_HYPFS 959 def_bool y 960 prompt "s390 hypervisor information" 961 help 962 This provides several binary files at (debugfs)/s390_hypfs/ to 963 provide accounting information in an s390 hypervisor environment. 964 965config S390_HYPFS_FS 966 def_bool n 967 prompt "s390 hypervisor file system support" 968 select SYS_HYPERVISOR 969 depends on S390_HYPFS 970 help 971 This is a virtual file system intended to provide accounting 972 information in an s390 hypervisor environment. This file system 973 is deprecated and should not be used. 974 975 Say N if you are unsure. 976 977source "arch/s390/kvm/Kconfig" 978 979config S390_GUEST 980 def_bool y 981 prompt "s390 support for virtio devices" 982 select TTY 983 select VIRTUALIZATION 984 select VIRTIO 985 help 986 Enabling this option adds support for virtio based paravirtual device 987 drivers on s390. 988 989 Select this option if you want to run the kernel as a guest under 990 the KVM hypervisor. 991 992endmenu 993 994config S390_MODULES_SANITY_TEST_HELPERS 995 def_bool n 996 997menu "Selftests" 998 999config S390_UNWIND_SELFTEST 1000 def_tristate n 1001 depends on KUNIT 1002 default KUNIT_ALL_TESTS 1003 prompt "Test unwind functions" 1004 help 1005 This option enables s390 specific stack unwinder testing kernel 1006 module. This option is not useful for distributions or general 1007 kernels, but only for kernel developers working on architecture code. 1008 1009 Say N if you are unsure. 1010 1011config S390_KPROBES_SANITY_TEST 1012 def_tristate n 1013 prompt "Enable s390 specific kprobes tests" 1014 depends on KPROBES 1015 depends on KUNIT 1016 help 1017 This option enables an s390 specific kprobes test module. This option 1018 is not useful for distributions or general kernels, but only for kernel 1019 developers working on architecture code. 1020 1021 Say N if you are unsure. 1022 1023config S390_MODULES_SANITY_TEST 1024 def_tristate n 1025 depends on KUNIT 1026 default KUNIT_ALL_TESTS 1027 prompt "Enable s390 specific modules tests" 1028 select S390_MODULES_SANITY_TEST_HELPERS 1029 help 1030 This option enables an s390 specific modules test. This option is 1031 not useful for distributions or general kernels, but only for 1032 kernel developers working on architecture code. 1033 1034 Say N if you are unsure. 1035endmenu 1036