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