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 CC_HAS_ASM_IMMEDIATE_STRINGS 73 def_bool !(CC_IS_GCC && GCC_VERSION < 90000) 74 help 75 GCC versions before 9.0.0 cannot handle strings as immediate 76 input operands in inline assemblies. 77 78config CC_HAS_STACKPROTECTOR_GLOBAL 79 def_bool $(cc-option, -mstack-protector-guard=global -mstack-protector-guard-record) 80 81config S390 82 def_bool y 83 # 84 # Note: keep this list sorted alphabetically 85 # 86 imply IMA_SECURE_AND_OR_TRUSTED_BOOT 87 select ALTERNATE_USER_ADDRESS_SPACE 88 select ARCH_32BIT_USTAT_F_TINODE 89 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 90 select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM 91 select ARCH_ENABLE_MEMORY_HOTREMOVE 92 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2 93 select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE 94 select ARCH_HAS_CC_CAN_LINK 95 select ARCH_HAS_CPU_FINALIZE_INIT 96 select ARCH_HAS_CURRENT_STACK_POINTER 97 select ARCH_HAS_DEBUG_VIRTUAL 98 select ARCH_HAS_DEBUG_VM_PGTABLE 99 select ARCH_HAS_DEBUG_WX 100 select ARCH_HAS_DEVMEM_IS_ALLOWED 101 select ARCH_HAS_DMA_OPS if PCI 102 select ARCH_HAS_ELF_RANDOMIZE 103 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 104 select ARCH_HAS_FORTIFY_SOURCE 105 select ARCH_HAS_GCOV_PROFILE_ALL 106 select ARCH_HAS_GIGANTIC_PAGE 107 select ARCH_HAS_KCOV 108 select ARCH_HAS_MEMBARRIER_SYNC_CORE 109 select ARCH_HAS_MEM_ENCRYPT 110 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 111 select ARCH_HAS_PREEMPT_LAZY 112 select ARCH_HAS_PTDUMP 113 select ARCH_HAS_PTE_SPECIAL 114 select ARCH_HAS_SCALED_CPUTIME 115 select ARCH_HAS_SET_DIRECT_MAP 116 select ARCH_HAS_SET_MEMORY 117 select ARCH_HAS_STRICT_KERNEL_RWX 118 select ARCH_HAS_STRICT_MODULE_RWX 119 select ARCH_HAS_SYSCALL_WRAPPER 120 select ARCH_HAS_UBSAN 121 select ARCH_HAS_VDSO_TIME_DATA 122 select ARCH_HAVE_NMI_SAFE_CMPXCHG 123 select ARCH_HAVE_TRACE_MMIO_ACCESS 124 select ARCH_INLINE_READ_LOCK 125 select ARCH_INLINE_READ_LOCK_BH 126 select ARCH_INLINE_READ_LOCK_IRQ 127 select ARCH_INLINE_READ_LOCK_IRQSAVE 128 select ARCH_INLINE_READ_TRYLOCK 129 select ARCH_INLINE_READ_UNLOCK 130 select ARCH_INLINE_READ_UNLOCK_BH 131 select ARCH_INLINE_READ_UNLOCK_IRQ 132 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE 133 select ARCH_INLINE_SPIN_LOCK 134 select ARCH_INLINE_SPIN_LOCK_BH 135 select ARCH_INLINE_SPIN_LOCK_IRQ 136 select ARCH_INLINE_SPIN_LOCK_IRQSAVE 137 select ARCH_INLINE_SPIN_TRYLOCK 138 select ARCH_INLINE_SPIN_TRYLOCK_BH 139 select ARCH_INLINE_SPIN_UNLOCK 140 select ARCH_INLINE_SPIN_UNLOCK_BH 141 select ARCH_INLINE_SPIN_UNLOCK_IRQ 142 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE 143 select ARCH_INLINE_WRITE_LOCK 144 select ARCH_INLINE_WRITE_LOCK_BH 145 select ARCH_INLINE_WRITE_LOCK_IRQ 146 select ARCH_INLINE_WRITE_LOCK_IRQSAVE 147 select ARCH_INLINE_WRITE_TRYLOCK 148 select ARCH_INLINE_WRITE_UNLOCK 149 select ARCH_INLINE_WRITE_UNLOCK_BH 150 select ARCH_INLINE_WRITE_UNLOCK_IRQ 151 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE 152 select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 153 select ARCH_STACKWALK 154 select ARCH_SUPPORTS_ATOMIC_RMW 155 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 156 select ARCH_SUPPORTS_HUGETLBFS 157 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && CC_IS_CLANG 158 select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 159 select ARCH_SUPPORTS_NUMA_BALANCING 160 select ARCH_SUPPORTS_PER_VMA_LOCK 161 select ARCH_USE_BUILTIN_BSWAP 162 select ARCH_USE_CMPXCHG_LOCKREF 163 select ARCH_USE_SYM_ANNOTATIONS 164 select ARCH_WANTS_NO_INSTR 165 select ARCH_WANT_DEFAULT_BPF_JIT 166 select ARCH_WANT_IPC_PARSE_VERSION 167 select ARCH_WANT_IRQS_OFF_ACTIVATE_MM 168 select ARCH_WANT_KERNEL_PMD_MKWRITE 169 select ARCH_WANT_LD_ORPHAN_WARN 170 select ARCH_WANTS_THP_SWAP 171 select BUILDTIME_TABLE_SORT 172 select CLONE_BACKWARDS2 173 select DCACHE_WORD_ACCESS if !KMSAN 174 select DYNAMIC_FTRACE if FUNCTION_TRACER 175 select FUNCTION_ALIGNMENT_8B if CC_IS_GCC 176 select FUNCTION_ALIGNMENT_16B if !CC_IS_GCC 177 select GENERIC_ALLOCATOR 178 select GENERIC_CPU_DEVICES 179 select GENERIC_CPU_AUTOPROBE 180 select GENERIC_CPU_VULNERABILITIES 181 select GENERIC_ENTRY 182 select GENERIC_GETTIMEOFDAY 183 select GENERIC_SMP_IDLE_THREAD 184 select GENERIC_TIME_VSYSCALL 185 select GENERIC_IOREMAP if PCI 186 select HAVE_ALIGNED_STRUCT_PAGE 187 select HAVE_ARCH_AUDITSYSCALL 188 select HAVE_ARCH_JUMP_LABEL 189 select HAVE_ARCH_JUMP_LABEL_RELATIVE 190 select HAVE_ARCH_KASAN 191 select HAVE_ARCH_KASAN_VMALLOC 192 select HAVE_ARCH_KCSAN 193 select HAVE_ARCH_KMSAN 194 select HAVE_ARCH_KFENCE 195 select HAVE_ARCH_KSTACK_ERASE 196 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 197 select HAVE_ARCH_SECCOMP_FILTER 198 select HAVE_ARCH_SOFT_DIRTY 199 select HAVE_ARCH_TRACEHOOK 200 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 201 select HAVE_ARCH_VMAP_STACK 202 select HAVE_ASM_MODVERSIONS 203 select HAVE_BUILDTIME_MCOUNT_SORT 204 select HAVE_CMPXCHG_DOUBLE 205 select HAVE_CMPXCHG_LOCAL 206 select HAVE_DEBUG_KMEMLEAK 207 select HAVE_DMA_CONTIGUOUS 208 select HAVE_DYNAMIC_FTRACE 209 select HAVE_DYNAMIC_FTRACE_WITH_ARGS 210 select HAVE_FTRACE_REGS_HAVING_PT_REGS 211 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 212 select HAVE_DYNAMIC_FTRACE_WITH_REGS 213 select HAVE_EBPF_JIT if HAVE_MARCH_Z196_FEATURES 214 select HAVE_EFFICIENT_UNALIGNED_ACCESS 215 select HAVE_GENERIC_TIF_BITS 216 select HAVE_GUP_FAST 217 select HAVE_FENTRY 218 select HAVE_FTRACE_GRAPH_FUNC 219 select HAVE_FUNCTION_ARG_ACCESS_API 220 select HAVE_FUNCTION_ERROR_INJECTION 221 select HAVE_FUNCTION_GRAPH_FREGS 222 select HAVE_FUNCTION_GRAPH_TRACER 223 select HAVE_FUNCTION_TRACER 224 select HAVE_GCC_PLUGINS 225 select HAVE_GENERIC_VDSO 226 select HAVE_IOREMAP_PROT if PCI 227 select HAVE_KERNEL_BZIP2 228 select HAVE_KERNEL_GZIP 229 select HAVE_KERNEL_LZ4 230 select HAVE_KERNEL_LZMA 231 select HAVE_KERNEL_LZO 232 select HAVE_KERNEL_UNCOMPRESSED 233 select HAVE_KERNEL_XZ 234 select HAVE_KERNEL_ZSTD 235 select HAVE_KPROBES 236 select HAVE_KPROBES_ON_FTRACE 237 select HAVE_KRETPROBES 238 select HAVE_LIVEPATCH 239 select HAVE_MEMBLOCK_PHYS_MAP 240 select HAVE_MOD_ARCH_SPECIFIC 241 select HAVE_NMI 242 select HAVE_NOP_MCOUNT 243 select HAVE_PAGE_SIZE_4KB 244 select HAVE_PCI 245 select HAVE_PERF_EVENTS 246 select HAVE_PERF_REGS 247 select HAVE_PERF_USER_STACK_DUMP 248 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 249 select HAVE_PREEMPT_DYNAMIC_KEY 250 select HAVE_REGS_AND_STACK_ACCESS_API 251 select HAVE_RELIABLE_STACKTRACE 252 select HAVE_RETHOOK 253 select HAVE_RSEQ 254 select HAVE_SAMPLE_FTRACE_DIRECT 255 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI 256 select HAVE_SETUP_PER_CPU_AREA 257 select HAVE_SOFTIRQ_ON_OWN_STACK 258 select HAVE_STACKPROTECTOR if CC_HAS_STACKPROTECTOR_GLOBAL 259 select HAVE_SYSCALL_TRACEPOINTS 260 select HAVE_VIRT_CPU_ACCOUNTING 261 select HAVE_VIRT_CPU_ACCOUNTING_IDLE 262 select HOTPLUG_SMT 263 select IOMMU_HELPER if PCI 264 select IOMMU_SUPPORT if PCI 265 select IRQ_MSI_LIB if PCI 266 select KASAN_VMALLOC if KASAN 267 select LOCK_MM_AND_FIND_VMA 268 select MMU_GATHER_MERGE_VMAS 269 select MMU_GATHER_NO_GATHER 270 select MMU_GATHER_RCU_TABLE_FREE 271 select MODULES_USE_ELF_RELA 272 select NEED_DMA_MAP_STATE if PCI 273 select NEED_PER_CPU_EMBED_FIRST_CHUNK 274 select NEED_PROC_VMCORE_DEVICE_RAM if PROC_VMCORE 275 select NEED_SG_DMA_LENGTH if PCI 276 select OLD_SIGACTION 277 select OLD_SIGSUSPEND3 278 select PCI_DOMAINS if PCI 279 select PCI_MSI if PCI 280 select PCI_MSI_ARCH_FALLBACKS if PCI_MSI 281 select PCI_QUIRKS if PCI 282 select SPARSE_IRQ 283 select SWIOTLB 284 select SYSCTL_EXCEPTION_TRACE 285 select THREAD_INFO_IN_TASK 286 select TRACE_IRQFLAGS_SUPPORT 287 select TTY 288 select USER_STACKTRACE_SUPPORT 289 select VDSO_GETRANDOM 290 select VIRT_CPU_ACCOUNTING 291 select VMAP_STACK 292 select ZONE_DMA 293 # Note: keep the above list sorted alphabetically 294 295config SCHED_OMIT_FRAME_POINTER 296 def_bool y 297 298config PGTABLE_LEVELS 299 int 300 default 5 301 302source "kernel/livepatch/Kconfig" 303 304config ARCH_CC_CAN_LINK 305 bool 306 default $(cc_can_link_user,-m64) 307 308config ARCH_USERFLAGS 309 string 310 default "-m64" 311 312config ARCH_SUPPORTS_KEXEC 313 def_bool y 314 315config ARCH_SUPPORTS_KEXEC_FILE 316 def_bool y 317 318config ARCH_SUPPORTS_KEXEC_SIG 319 def_bool MODULE_SIG_FORMAT 320 321config ARCH_SUPPORTS_KEXEC_PURGATORY 322 def_bool y 323 324config ARCH_SUPPORTS_CRASH_DUMP 325 def_bool y 326 help 327 Refer to <file:Documentation/arch/s390/zfcpdump.rst> for more details on this. 328 This option also enables s390 zfcpdump. 329 See also <file:Documentation/arch/s390/zfcpdump.rst> 330 331config ARCH_DEFAULT_CRASH_DUMP 332 def_bool y 333 334menu "Processor type and features" 335 336config HAVE_MARCH_Z10_FEATURES 337 def_bool n 338 339config HAVE_MARCH_Z196_FEATURES 340 def_bool n 341 select HAVE_MARCH_Z10_FEATURES 342 343config HAVE_MARCH_ZEC12_FEATURES 344 def_bool n 345 select HAVE_MARCH_Z196_FEATURES 346 347config HAVE_MARCH_Z13_FEATURES 348 def_bool n 349 select HAVE_MARCH_ZEC12_FEATURES 350 351config HAVE_MARCH_Z14_FEATURES 352 def_bool n 353 select HAVE_MARCH_Z13_FEATURES 354 355config HAVE_MARCH_Z15_FEATURES 356 def_bool n 357 select HAVE_MARCH_Z14_FEATURES 358 359config HAVE_MARCH_Z16_FEATURES 360 def_bool n 361 select HAVE_MARCH_Z15_FEATURES 362 363config HAVE_MARCH_Z17_FEATURES 364 def_bool n 365 select HAVE_MARCH_Z16_FEATURES 366 367choice 368 prompt "Processor type" 369 default MARCH_Z196 370 371config MARCH_Z10 372 bool "IBM System z10" 373 select HAVE_MARCH_Z10_FEATURES 374 depends on $(cc-option,-march=z10) 375 help 376 Select this to enable optimizations for IBM System z10 (2097 and 2098 377 series). This is the oldest machine generation currently supported. 378 379config MARCH_Z196 380 bool "IBM zEnterprise 114 and 196" 381 select HAVE_MARCH_Z196_FEATURES 382 depends on $(cc-option,-march=z196) 383 help 384 Select this to enable optimizations for IBM zEnterprise 114 and 196 385 (2818 and 2817 series). The kernel will be slightly faster but will 386 not work on older machines. 387 388config MARCH_ZEC12 389 bool "IBM zBC12 and zEC12" 390 select HAVE_MARCH_ZEC12_FEATURES 391 depends on $(cc-option,-march=zEC12) 392 help 393 Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and 394 2827 series). The kernel will be slightly faster but will not work on 395 older machines. 396 397config MARCH_Z13 398 bool "IBM z13s and z13" 399 select HAVE_MARCH_Z13_FEATURES 400 depends on $(cc-option,-march=z13) 401 help 402 Select this to enable optimizations for IBM z13s and z13 (2965 and 403 2964 series). The kernel will be slightly faster but will not work on 404 older machines. 405 406config MARCH_Z14 407 bool "IBM z14 ZR1 and z14" 408 select HAVE_MARCH_Z14_FEATURES 409 depends on $(cc-option,-march=z14) 410 help 411 Select this to enable optimizations for IBM z14 ZR1 and z14 (3907 412 and 3906 series). The kernel will be slightly faster but will not 413 work on older machines. 414 415config MARCH_Z15 416 bool "IBM z15" 417 select HAVE_MARCH_Z15_FEATURES 418 depends on $(cc-option,-march=z15) 419 help 420 Select this to enable optimizations for IBM z15 (8562 421 and 8561 series). The kernel will be slightly faster but will not 422 work on older machines. 423 424config MARCH_Z16 425 bool "IBM z16" 426 select HAVE_MARCH_Z16_FEATURES 427 depends on $(cc-option,-march=z16) 428 help 429 Select this to enable optimizations for IBM z16 (3931 and 430 3932 series). 431 432config MARCH_Z17 433 bool "IBM z17" 434 select HAVE_MARCH_Z17_FEATURES 435 depends on $(cc-option,-march=z17) 436 help 437 Select this to enable optimizations for IBM z17 (9175 and 438 9176 series). 439 440endchoice 441 442config MARCH_Z10_TUNE 443 def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT 444 445config MARCH_Z196_TUNE 446 def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT 447 448config MARCH_ZEC12_TUNE 449 def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT 450 451config MARCH_Z13_TUNE 452 def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT 453 454config MARCH_Z14_TUNE 455 def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT 456 457config MARCH_Z15_TUNE 458 def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT 459 460config MARCH_Z16_TUNE 461 def_bool TUNE_Z16 || MARCH_Z16 && TUNE_DEFAULT 462 463config MARCH_Z17_TUNE 464 def_bool TUNE_Z17 || MARCH_Z17 && TUNE_DEFAULT 465 466choice 467 prompt "Tune code generation" 468 default TUNE_DEFAULT 469 help 470 Cause the compiler to tune (-mtune) the generated code for a machine. 471 This will make the code run faster on the selected machine but 472 somewhat slower on other machines. 473 This option only changes how the compiler emits instructions, not the 474 selection of instructions itself, so the resulting kernel will run on 475 all other machines. 476 477config TUNE_DEFAULT 478 bool "Default" 479 help 480 Tune the generated code for the target processor for which the kernel 481 will be compiled. 482 483config TUNE_Z10 484 bool "IBM System z10" 485 486config TUNE_Z196 487 bool "IBM zEnterprise 114 and 196" 488 depends on $(cc-option,-mtune=z196) 489 490config TUNE_ZEC12 491 bool "IBM zBC12 and zEC12" 492 depends on $(cc-option,-mtune=zEC12) 493 494config TUNE_Z13 495 bool "IBM z13s and z13" 496 depends on $(cc-option,-mtune=z13) 497 498config TUNE_Z14 499 bool "IBM z14 ZR1 and z14" 500 depends on $(cc-option,-mtune=z14) 501 502config TUNE_Z15 503 bool "IBM z15" 504 depends on $(cc-option,-mtune=z15) 505 506config TUNE_Z16 507 bool "IBM z16" 508 depends on $(cc-option,-mtune=z16) 509 510config TUNE_Z17 511 bool "IBM z17" 512 depends on $(cc-option,-mtune=z17) 513 514endchoice 515 516config 64BIT 517 def_bool y 518 519config COMMAND_LINE_SIZE 520 int "Maximum size of kernel command line" 521 default 4096 522 range 896 1048576 523 help 524 This allows you to specify the maximum length of the kernel command 525 line. 526 527config SMP 528 def_bool y 529 530config NR_CPUS 531 int "Maximum number of CPUs (2-512)" 532 range 2 512 533 default "64" 534 help 535 This allows you to specify the maximum number of CPUs which this 536 kernel will support. The maximum supported value is 512 and the 537 minimum value which makes sense is 2. 538 539 This is purely to save memory - each supported CPU adds 540 approximately sixteen kilobytes to the kernel image. 541 542config HOTPLUG_CPU 543 def_bool y 544 545config NUMA 546 bool "NUMA support" 547 depends on SCHED_TOPOLOGY 548 default n 549 help 550 Enable NUMA support 551 552 This option adds NUMA support to the kernel. 553 554config NODES_SHIFT 555 int 556 depends on NUMA 557 default "1" 558 559config SCHED_TOPOLOGY 560 def_bool y 561 prompt "Topology scheduler support" 562 select ARCH_SUPPORTS_SCHED_SMT 563 select ARCH_SUPPORTS_SCHED_MC 564 select SCHED_SMT 565 select SCHED_MC 566 help 567 Topology scheduler support improves the CPU scheduler's decision 568 making when dealing with machines that have multi-threading, 569 multiple cores or multiple books. 570 571config SCHED_TOPOLOGY_VERTICAL 572 def_bool y 573 bool "Use vertical CPU polarization by default" 574 depends on SCHED_TOPOLOGY 575 help 576 Use vertical CPU polarization by default if available. 577 The default CPU polarization is horizontal. 578 579config HIPERDISPATCH_ON 580 def_bool y 581 bool "Use hiperdispatch on vertical polarization by default" 582 depends on SCHED_TOPOLOGY 583 depends on PROC_SYSCTL 584 help 585 Hiperdispatch aims to improve the CPU scheduler's decision 586 making when using vertical polarization by adjusting CPU 587 capacities dynamically. Set this option to use hiperdispatch 588 on vertical polarization by default. This can be overwritten 589 by sysctl's s390.hiperdispatch attribute later on. 590 591source "kernel/Kconfig.hz" 592 593config CERT_STORE 594 bool "Get user certificates via DIAG320" 595 depends on KEYS 596 select CRYPTO_LIB_SHA256 597 help 598 Enable this option if you want to access user-provided secure boot 599 certificates via DIAG 0x320. 600 601 These certificates will be made available via the keyring named 602 'cert_store'. 603 604config KERNEL_NOBP 605 def_bool n 606 prompt "Enable modified branch prediction for the kernel by default" 607 help 608 If this option is selected the kernel will switch to a modified 609 branch prediction mode if the firmware interface is available. 610 The modified branch prediction mode improves the behaviour in 611 regard to speculative execution. 612 613 With the option enabled the kernel parameter "nobp=0" or "nospec" 614 can be used to run the kernel in the normal branch prediction mode. 615 616 With the option disabled the modified branch prediction mode is 617 enabled with the "nobp=1" kernel parameter. 618 619 If unsure, say N. 620 621config EXPOLINE 622 def_bool n 623 depends on $(cc-option,-mindirect-branch=thunk) 624 prompt "Avoid speculative indirect branches in the kernel" 625 help 626 Compile the kernel with the expoline compiler options to guard 627 against kernel-to-user data leaks by avoiding speculative indirect 628 branches. 629 Requires a compiler with -mindirect-branch=thunk support for full 630 protection. The kernel may run slower. 631 632 If unsure, say N. 633 634config EXPOLINE_EXTERN 635 def_bool EXPOLINE && CC_IS_GCC && GCC_VERSION >= 110200 && \ 636 $(success,$(srctree)/arch/s390/tools/gcc-thunk-extern.sh $(CC)) 637 help 638 Generate expolines as external functions if the compiler supports it. 639 This option is required for some tooling like kpatch, if expolines 640 are enabled. The kernel is compiled with 641 -mindirect-branch=thunk-extern, which requires a newer compiler. 642 643choice 644 prompt "Expoline default" 645 depends on EXPOLINE 646 default EXPOLINE_FULL 647 648config EXPOLINE_OFF 649 bool "spectre_v2=off" 650 651config EXPOLINE_AUTO 652 bool "spectre_v2=auto" 653 654config EXPOLINE_FULL 655 bool "spectre_v2=on" 656 657endchoice 658 659config RELOCATABLE 660 def_bool y 661 select ARCH_VMLINUX_NEEDS_RELOCS 662 help 663 This builds a kernel image that retains relocation information 664 so it can be loaded at an arbitrary address. 665 The relocations make the kernel image about 15% larger (compressed 666 10%), but are discarded at runtime. 667 Note: this option exists only for documentation purposes, please do 668 not remove it. 669 670config RANDOMIZE_BASE 671 bool "Randomize the address of the kernel image (KASLR)" 672 default y 673 help 674 In support of Kernel Address Space Layout Randomization (KASLR), 675 this randomizes the address at which the kernel image is loaded, 676 as a security feature that deters exploit attempts relying on 677 knowledge of the location of kernel internals. 678 679config RANDOMIZE_IDENTITY_BASE 680 bool "Randomize the address of the identity mapping base" 681 depends on RANDOMIZE_BASE 682 default DEBUG_VM 683 help 684 The identity mapping base address is pinned to zero by default. 685 Allow randomization of that base to expose otherwise missed 686 notion of physical and virtual addresses of data structures. 687 That does not have any impact on the base address at which the 688 kernel image is loaded. 689 690 If unsure, say N 691 692config KERNEL_IMAGE_BASE 693 hex "Kernel image base address" 694 range 0x100000 0x1FFFFFE0000000 if !KASAN 695 range 0x100000 0x1BFFFFE0000000 if KASAN 696 default 0x3FFE0000000 if !KASAN 697 default 0x7FFFE0000000 if KASAN 698 help 699 This is the address at which the kernel image is loaded in case 700 Kernel Address Space Layout Randomization (KASLR) is disabled. 701 702 In case the Protected virtualization guest support is enabled the 703 Ultravisor imposes a virtual address limit. If the value of this 704 option leads to the kernel image exceeding the Ultravisor limit, 705 this option is ignored and the image is loaded below the limit. 706 707 If the value of this option leads to the kernel image overlapping 708 the virtual memory where other data structures are located, this 709 option is ignored and the image is loaded above the structures. 710 711endmenu 712 713menu "Memory setup" 714 715config ARCH_SPARSEMEM_ENABLE 716 def_bool y 717 select SPARSEMEM_VMEMMAP_ENABLE 718 719config ARCH_SPARSEMEM_DEFAULT 720 def_bool y 721 722config ILLEGAL_POINTER_VALUE 723 hex 724 default 0xdead000000000000 725 726config MAX_PHYSMEM_BITS 727 int "Maximum size of supported physical memory in bits (42-53)" 728 range 42 53 729 default "46" 730 help 731 This option specifies the maximum supported size of physical memory 732 in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB). 733 Increasing the number of bits also increases the kernel image size. 734 By default 46 bits (64TB) are supported. 735 736endmenu 737 738menu "I/O subsystem" 739 740config QDIO 741 def_tristate y 742 prompt "QDIO support" 743 help 744 This driver provides the Queued Direct I/O base support for 745 IBM System z. 746 747 To compile this driver as a module, choose M here: the 748 module will be called qdio. 749 750 If unsure, say Y. 751 752if PCI 753 754config PCI_NR_FUNCTIONS 755 int "Maximum number of PCI functions (1-4096)" 756 range 1 4096 757 default "512" 758 help 759 This allows you to specify the maximum number of PCI functions which 760 this kernel will support. 761 762endif # PCI 763 764config HAS_IOMEM 765 def_bool PCI 766 767config CHSC_SCH 768 def_tristate m 769 prompt "Support for CHSC subchannels" 770 help 771 This driver allows usage of CHSC subchannels. A CHSC subchannel 772 is usually present on LPAR only. 773 The driver creates a device /dev/chsc, which may be used to 774 obtain I/O configuration information about the machine and 775 to issue asynchronous chsc commands (DANGEROUS). 776 You will usually only want to use this interface on a special 777 LPAR designated for system management. 778 779 To compile this driver as a module, choose M here: the 780 module will be called chsc_sch. 781 782 If unsure, say N. 783 784config SCM_BUS 785 def_bool y 786 prompt "SCM bus driver" 787 help 788 Bus driver for Storage Class Memory. 789 790config EADM_SCH 791 def_tristate m 792 prompt "Support for EADM subchannels" 793 depends on SCM_BUS 794 help 795 This driver allows usage of EADM subchannels. EADM subchannels act 796 as a communication vehicle for SCM increments. 797 798 To compile this driver as a module, choose M here: the 799 module will be called eadm_sch. 800 801config AP 802 def_tristate y 803 prompt "Support for Adjunct Processors (ap)" 804 help 805 This driver allows usage to Adjunct Processor (AP) devices via 806 the ap bus, cards and queues. Supported Adjunct Processors are 807 the CryptoExpress Cards (CEX). 808 809 To compile this driver as a module, choose M here: the 810 module will be called ap. 811 812 If unsure, say Y (default). 813 814config AP_DEBUG 815 def_bool n 816 prompt "Enable debug features for Adjunct Processor (ap) devices" 817 depends on AP 818 help 819 Say 'Y' here to enable some additional debug features for Adjunct 820 Processor (ap) devices. 821 822 There will be some more sysfs attributes displayed for ap queues. 823 824 Do not enable on production level kernel build. 825 826 If unsure, say N. 827 828config VFIO_CCW 829 def_tristate n 830 prompt "Support for VFIO-CCW subchannels" 831 depends on VFIO 832 select VFIO_MDEV 833 help 834 This driver allows usage of I/O subchannels via VFIO-CCW. 835 836 To compile this driver as a module, choose M here: the 837 module will be called vfio_ccw. 838 839config VFIO_AP 840 def_tristate n 841 prompt "VFIO support for AP devices" 842 depends on KVM 843 depends on VFIO 844 depends on AP 845 select VFIO_MDEV 846 help 847 This driver grants access to Adjunct Processor (AP) devices 848 via the VFIO mediated device interface. 849 850 To compile this driver as a module, choose M here: the module 851 will be called vfio_ap. 852 853endmenu 854 855config CCW 856 def_bool y 857 858config HAVE_PNETID 859 tristate 860 default (SMC || CCWGROUP) 861 862menu "Virtualization" 863 864config PFAULT 865 def_bool y 866 prompt "Pseudo page fault support" 867 help 868 Select this option, if you want to use PFAULT pseudo page fault 869 handling under VM. If running native or in LPAR, this option 870 has no effect. If your VM does not support PFAULT, PAGEEX 871 pseudo page fault handling will be used. 872 Note that VM 4.2 supports PFAULT but has a bug in its 873 implementation that causes some problems. 874 Everybody who wants to run Linux under VM != VM4.2 should select 875 this option. 876 877config CMM 878 def_tristate n 879 prompt "Cooperative memory management" 880 help 881 Select this option, if you want to enable the kernel interface 882 to reduce the memory size of the system. This is accomplished 883 by allocating pages of memory and put them "on hold". This only 884 makes sense for a system running under VM where the unused pages 885 will be reused by VM for other guest systems. The interface 886 allows an external monitor to balance memory of many systems. 887 Everybody who wants to run Linux under VM should select this 888 option. 889 890config CMM_IUCV 891 def_bool y 892 prompt "IUCV special message interface to cooperative memory management" 893 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV) 894 help 895 Select this option to enable the special message interface to 896 the cooperative memory management. 897 898config APPLDATA_BASE 899 def_bool n 900 prompt "Linux - VM Monitor Stream, base infrastructure" 901 depends on PROC_SYSCTL 902 help 903 This provides a kernel interface for creating and updating z/VM APPLDATA 904 monitor records. The monitor records are updated at certain time 905 intervals, once the timer is started. 906 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer, 907 i.e. enables or disables monitoring on the Linux side. 908 A custom interval value (in seconds) can be written to 909 /proc/appldata/interval. 910 911 Defaults are 60 seconds interval and timer off. 912 The /proc entries can also be read from, showing the current settings. 913 914config APPLDATA_MEM 915 def_tristate m 916 prompt "Monitor memory management statistics" 917 depends on APPLDATA_BASE && VM_EVENT_COUNTERS 918 help 919 This provides memory management related data to the Linux - VM Monitor 920 Stream, like paging/swapping rate, memory utilisation, etc. 921 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM 922 APPLDATA monitor record, i.e. enables or disables monitoring this record 923 on the z/VM side. 924 925 Default is disabled. 926 The /proc entry can also be read from, showing the current settings. 927 928 This can also be compiled as a module, which will be called 929 appldata_mem.o. 930 931config APPLDATA_OS 932 def_tristate m 933 prompt "Monitor OS statistics" 934 depends on APPLDATA_BASE 935 help 936 This provides OS related data to the Linux - VM Monitor Stream, like 937 CPU utilisation, etc. 938 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM 939 APPLDATA monitor record, i.e. enables or disables monitoring this record 940 on the z/VM side. 941 942 Default is disabled. 943 This can also be compiled as a module, which will be called 944 appldata_os.o. 945 946config APPLDATA_NET_SUM 947 def_tristate m 948 prompt "Monitor overall network statistics" 949 depends on APPLDATA_BASE && NET 950 help 951 This provides network related data to the Linux - VM Monitor Stream, 952 currently there is only a total sum of network I/O statistics, no 953 per-interface data. 954 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM 955 APPLDATA monitor record, i.e. enables or disables monitoring this record 956 on the z/VM side. 957 958 Default is disabled. 959 This can also be compiled as a module, which will be called 960 appldata_net_sum.o. 961 962config S390_HYPFS 963 def_bool y 964 prompt "s390 hypervisor information" 965 help 966 This provides several binary files at (debugfs)/s390_hypfs/ to 967 provide accounting information in an s390 hypervisor environment. 968 969config S390_HYPFS_FS 970 def_bool n 971 prompt "s390 hypervisor file system support" 972 select SYS_HYPERVISOR 973 depends on S390_HYPFS 974 help 975 This is a virtual file system intended to provide accounting 976 information in an s390 hypervisor environment. This file system 977 is deprecated and should not be used. 978 979 Say N if you are unsure. 980 981source "arch/s390/kvm/Kconfig" 982 983config S390_GUEST 984 def_bool y 985 prompt "s390 support for virtio devices" 986 select TTY 987 select VIRTUALIZATION 988 select VIRTIO 989 help 990 Enabling this option adds support for virtio based paravirtual device 991 drivers on s390. 992 993 Select this option if you want to run the kernel as a guest under 994 the KVM hypervisor. 995 996endmenu 997 998config S390_MODULES_SANITY_TEST_HELPERS 999 def_bool n 1000 1001menu "Selftests" 1002 1003config S390_UNWIND_SELFTEST 1004 def_tristate n 1005 depends on KUNIT 1006 default KUNIT_ALL_TESTS 1007 prompt "Test unwind functions" 1008 help 1009 This option enables s390 specific stack unwinder testing kernel 1010 module. This option is not useful for distributions or general 1011 kernels, but only for kernel developers working on architecture code. 1012 1013 Say N if you are unsure. 1014 1015config S390_KPROBES_SANITY_TEST 1016 def_tristate n 1017 prompt "Enable s390 specific kprobes tests" 1018 depends on KPROBES 1019 depends on KUNIT 1020 help 1021 This option enables an s390 specific kprobes test module. This option 1022 is not useful for distributions or general kernels, but only for kernel 1023 developers working on architecture code. 1024 1025 Say N if you are unsure. 1026 1027config S390_MODULES_SANITY_TEST 1028 def_tristate n 1029 depends on KUNIT 1030 default KUNIT_ALL_TESTS 1031 prompt "Enable s390 specific modules tests" 1032 select S390_MODULES_SANITY_TEST_HELPERS 1033 help 1034 This option enables an s390 specific modules test. This option is 1035 not useful for distributions or general kernels, but only for 1036 kernel developers working on architecture code. 1037 1038 Say N if you are unsure. 1039endmenu 1040