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 GENERIC_HWEIGHT 21 def_bool y 22 23config GENERIC_BUG 24 def_bool y if BUG 25 26config GENERIC_BUG_RELATIVE_POINTERS 27 def_bool y 28 29config GENERIC_LOCKBREAK 30 def_bool y if PREEMPTION 31 32config PGSTE 33 def_bool y if KVM 34 35config AUDIT_ARCH 36 def_bool y 37 38config NO_IOPORT_MAP 39 def_bool y 40 41config PCI_QUIRKS 42 def_bool n 43 44config ARCH_SUPPORTS_UPROBES 45 def_bool y 46 47config KASAN_SHADOW_OFFSET 48 hex 49 depends on KASAN 50 default 0x18000000000000 51 52config S390 53 def_bool y 54 # 55 # Note: keep this list sorted alphabetically 56 # 57 imply IMA_SECURE_AND_OR_TRUSTED_BOOT 58 select ARCH_32BIT_USTAT_F_TINODE 59 select ARCH_BINFMT_ELF_STATE 60 select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM 61 select ARCH_ENABLE_MEMORY_HOTREMOVE 62 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2 63 select ARCH_HAS_DEBUG_VM_PGTABLE 64 select ARCH_HAS_DEBUG_WX 65 select ARCH_HAS_DEVMEM_IS_ALLOWED 66 select ARCH_HAS_ELF_RANDOMIZE 67 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 68 select ARCH_HAS_FORTIFY_SOURCE 69 select ARCH_HAS_GCOV_PROFILE_ALL 70 select ARCH_HAS_GIGANTIC_PAGE 71 select ARCH_HAS_KCOV 72 select ARCH_HAS_MEM_ENCRYPT 73 select ARCH_HAS_PTE_SPECIAL 74 select ARCH_HAS_SCALED_CPUTIME 75 select ARCH_HAS_SET_MEMORY 76 select ARCH_HAS_STRICT_KERNEL_RWX 77 select ARCH_HAS_STRICT_MODULE_RWX 78 select ARCH_HAS_SYSCALL_WRAPPER 79 select ARCH_HAS_UBSAN_SANITIZE_ALL 80 select ARCH_HAS_VDSO_DATA 81 select ARCH_HAVE_NMI_SAFE_CMPXCHG 82 select ARCH_INLINE_READ_LOCK 83 select ARCH_INLINE_READ_LOCK_BH 84 select ARCH_INLINE_READ_LOCK_IRQ 85 select ARCH_INLINE_READ_LOCK_IRQSAVE 86 select ARCH_INLINE_READ_TRYLOCK 87 select ARCH_INLINE_READ_UNLOCK 88 select ARCH_INLINE_READ_UNLOCK_BH 89 select ARCH_INLINE_READ_UNLOCK_IRQ 90 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE 91 select ARCH_INLINE_SPIN_LOCK 92 select ARCH_INLINE_SPIN_LOCK_BH 93 select ARCH_INLINE_SPIN_LOCK_IRQ 94 select ARCH_INLINE_SPIN_LOCK_IRQSAVE 95 select ARCH_INLINE_SPIN_TRYLOCK 96 select ARCH_INLINE_SPIN_TRYLOCK_BH 97 select ARCH_INLINE_SPIN_UNLOCK 98 select ARCH_INLINE_SPIN_UNLOCK_BH 99 select ARCH_INLINE_SPIN_UNLOCK_IRQ 100 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE 101 select ARCH_INLINE_WRITE_LOCK 102 select ARCH_INLINE_WRITE_LOCK_BH 103 select ARCH_INLINE_WRITE_LOCK_IRQ 104 select ARCH_INLINE_WRITE_LOCK_IRQSAVE 105 select ARCH_INLINE_WRITE_TRYLOCK 106 select ARCH_INLINE_WRITE_UNLOCK 107 select ARCH_INLINE_WRITE_UNLOCK_BH 108 select ARCH_INLINE_WRITE_UNLOCK_IRQ 109 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE 110 select ARCH_STACKWALK 111 select ARCH_SUPPORTS_ATOMIC_RMW 112 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 113 select ARCH_SUPPORTS_NUMA_BALANCING 114 select ARCH_USE_BUILTIN_BSWAP 115 select ARCH_USE_CMPXCHG_LOCKREF 116 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 117 select ARCH_WANTS_NO_INSTR 118 select ARCH_WANT_DEFAULT_BPF_JIT 119 select ARCH_WANT_IPC_PARSE_VERSION 120 select BUILDTIME_TABLE_SORT 121 select CLONE_BACKWARDS2 122 select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES 123 select DMA_OPS if PCI 124 select DYNAMIC_FTRACE if FUNCTION_TRACER 125 select GENERIC_ALLOCATOR 126 select GENERIC_CPU_AUTOPROBE 127 select GENERIC_CPU_VULNERABILITIES 128 select GENERIC_ENTRY 129 select GENERIC_FIND_FIRST_BIT 130 select GENERIC_GETTIMEOFDAY 131 select GENERIC_PTDUMP 132 select GENERIC_SMP_IDLE_THREAD 133 select GENERIC_TIME_VSYSCALL 134 select GENERIC_VDSO_TIME_NS 135 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 136 select HAVE_ARCH_AUDITSYSCALL 137 select HAVE_ARCH_JUMP_LABEL 138 select HAVE_ARCH_JUMP_LABEL_RELATIVE 139 select HAVE_ARCH_KASAN 140 select HAVE_ARCH_KASAN_VMALLOC 141 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 142 select HAVE_ARCH_SECCOMP_FILTER 143 select HAVE_ARCH_SOFT_DIRTY 144 select HAVE_ARCH_TRACEHOOK 145 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 146 select HAVE_ARCH_VMAP_STACK 147 select HAVE_ASM_MODVERSIONS 148 select HAVE_CMPXCHG_DOUBLE 149 select HAVE_CMPXCHG_LOCAL 150 select HAVE_DEBUG_KMEMLEAK 151 select HAVE_DMA_CONTIGUOUS 152 select HAVE_DYNAMIC_FTRACE 153 select HAVE_DYNAMIC_FTRACE_WITH_REGS 154 select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES 155 select HAVE_EFFICIENT_UNALIGNED_ACCESS 156 select HAVE_FAST_GUP 157 select HAVE_FENTRY 158 select HAVE_FTRACE_MCOUNT_RECORD 159 select HAVE_FUNCTION_ERROR_INJECTION 160 select HAVE_FUNCTION_GRAPH_TRACER 161 select HAVE_FUNCTION_TRACER 162 select HAVE_FUTEX_CMPXCHG if FUTEX 163 select HAVE_GCC_PLUGINS 164 select HAVE_GENERIC_VDSO 165 select HAVE_IOREMAP_PROT if PCI 166 select HAVE_KERNEL_BZIP2 167 select HAVE_KERNEL_GZIP 168 select HAVE_KERNEL_LZ4 169 select HAVE_KERNEL_LZMA 170 select HAVE_KERNEL_LZO 171 select HAVE_KERNEL_UNCOMPRESSED 172 select HAVE_KERNEL_XZ 173 select HAVE_KERNEL_ZSTD 174 select HAVE_KPROBES 175 select HAVE_KPROBES_ON_FTRACE 176 select HAVE_KRETPROBES 177 select HAVE_KVM 178 select HAVE_LIVEPATCH 179 select HAVE_MEMBLOCK_PHYS_MAP 180 select HAVE_MOD_ARCH_SPECIFIC 181 select HAVE_NMI 182 select HAVE_NOP_MCOUNT 183 select HAVE_PCI 184 select HAVE_PERF_EVENTS 185 select HAVE_PERF_REGS 186 select HAVE_PERF_USER_STACK_DUMP 187 select HAVE_REGS_AND_STACK_ACCESS_API 188 select HAVE_RELIABLE_STACKTRACE 189 select HAVE_RSEQ 190 select HAVE_SOFTIRQ_ON_OWN_STACK 191 select HAVE_SYSCALL_TRACEPOINTS 192 select HAVE_VIRT_CPU_ACCOUNTING 193 select HAVE_VIRT_CPU_ACCOUNTING_IDLE 194 select IOMMU_HELPER if PCI 195 select IOMMU_SUPPORT if PCI 196 select MMU_GATHER_NO_GATHER 197 select MMU_GATHER_RCU_TABLE_FREE 198 select MODULES_USE_ELF_RELA 199 select NEED_DMA_MAP_STATE if PCI 200 select NEED_SG_DMA_LENGTH if PCI 201 select OLD_SIGACTION 202 select OLD_SIGSUSPEND3 203 select PCI_DOMAINS if PCI 204 select PCI_MSI if PCI 205 select PCI_MSI_ARCH_FALLBACKS if PCI_MSI 206 select SPARSE_IRQ 207 select SWIOTLB 208 select SYSCTL_EXCEPTION_TRACE 209 select THREAD_INFO_IN_TASK 210 select TTY 211 select VIRT_CPU_ACCOUNTING 212 select ZONE_DMA 213 # Note: keep the above list sorted alphabetically 214 215config SCHED_OMIT_FRAME_POINTER 216 def_bool y 217 218config PGTABLE_LEVELS 219 int 220 default 5 221 222source "kernel/livepatch/Kconfig" 223 224menu "Processor type and features" 225 226config HAVE_MARCH_Z900_FEATURES 227 def_bool n 228 229config HAVE_MARCH_Z990_FEATURES 230 def_bool n 231 select HAVE_MARCH_Z900_FEATURES 232 233config HAVE_MARCH_Z9_109_FEATURES 234 def_bool n 235 select HAVE_MARCH_Z990_FEATURES 236 237config HAVE_MARCH_Z10_FEATURES 238 def_bool n 239 select HAVE_MARCH_Z9_109_FEATURES 240 241config HAVE_MARCH_Z196_FEATURES 242 def_bool n 243 select HAVE_MARCH_Z10_FEATURES 244 245config HAVE_MARCH_ZEC12_FEATURES 246 def_bool n 247 select HAVE_MARCH_Z196_FEATURES 248 249config HAVE_MARCH_Z13_FEATURES 250 def_bool n 251 select HAVE_MARCH_ZEC12_FEATURES 252 253config HAVE_MARCH_Z14_FEATURES 254 def_bool n 255 select HAVE_MARCH_Z13_FEATURES 256 257config HAVE_MARCH_Z15_FEATURES 258 def_bool n 259 select HAVE_MARCH_Z14_FEATURES 260 261choice 262 prompt "Processor type" 263 default MARCH_Z196 264 265config MARCH_Z900 266 bool "IBM zSeries model z800 and z900" 267 select HAVE_MARCH_Z900_FEATURES 268 depends on $(cc-option,-march=z900) 269 help 270 Select this to enable optimizations for model z800/z900 (2064 and 271 2066 series). This will enable some optimizations that are not 272 available on older ESA/390 (31 Bit) only CPUs. 273 274config MARCH_Z990 275 bool "IBM zSeries model z890 and z990" 276 select HAVE_MARCH_Z990_FEATURES 277 depends on $(cc-option,-march=z990) 278 help 279 Select this to enable optimizations for model z890/z990 (2084 and 280 2086 series). The kernel will be slightly faster but will not work 281 on older machines. 282 283config MARCH_Z9_109 284 bool "IBM System z9" 285 select HAVE_MARCH_Z9_109_FEATURES 286 depends on $(cc-option,-march=z9-109) 287 help 288 Select this to enable optimizations for IBM System z9 (2094 and 289 2096 series). The kernel will be slightly faster but will not work 290 on older machines. 291 292config MARCH_Z10 293 bool "IBM System z10" 294 select HAVE_MARCH_Z10_FEATURES 295 depends on $(cc-option,-march=z10) 296 help 297 Select this to enable optimizations for IBM System z10 (2097 and 298 2098 series). The kernel will be slightly faster but will not work 299 on older machines. 300 301config MARCH_Z196 302 bool "IBM zEnterprise 114 and 196" 303 select HAVE_MARCH_Z196_FEATURES 304 depends on $(cc-option,-march=z196) 305 help 306 Select this to enable optimizations for IBM zEnterprise 114 and 196 307 (2818 and 2817 series). The kernel will be slightly faster but will 308 not work on older machines. 309 310config MARCH_ZEC12 311 bool "IBM zBC12 and zEC12" 312 select HAVE_MARCH_ZEC12_FEATURES 313 depends on $(cc-option,-march=zEC12) 314 help 315 Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and 316 2827 series). The kernel will be slightly faster but will not work on 317 older machines. 318 319config MARCH_Z13 320 bool "IBM z13s and z13" 321 select HAVE_MARCH_Z13_FEATURES 322 depends on $(cc-option,-march=z13) 323 help 324 Select this to enable optimizations for IBM z13s and z13 (2965 and 325 2964 series). The kernel will be slightly faster but will not work on 326 older machines. 327 328config MARCH_Z14 329 bool "IBM z14 ZR1 and z14" 330 select HAVE_MARCH_Z14_FEATURES 331 depends on $(cc-option,-march=z14) 332 help 333 Select this to enable optimizations for IBM z14 ZR1 and z14 (3907 334 and 3906 series). The kernel will be slightly faster but will not 335 work on older machines. 336 337config MARCH_Z15 338 bool "IBM z15" 339 select HAVE_MARCH_Z15_FEATURES 340 depends on $(cc-option,-march=z15) 341 help 342 Select this to enable optimizations for IBM z15 (8562 343 and 8561 series). The kernel will be slightly faster but will not 344 work on older machines. 345 346endchoice 347 348config MARCH_Z900_TUNE 349 def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT 350 351config MARCH_Z990_TUNE 352 def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT 353 354config MARCH_Z9_109_TUNE 355 def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT 356 357config MARCH_Z10_TUNE 358 def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT 359 360config MARCH_Z196_TUNE 361 def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT 362 363config MARCH_ZEC12_TUNE 364 def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT 365 366config MARCH_Z13_TUNE 367 def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT 368 369config MARCH_Z14_TUNE 370 def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT 371 372config MARCH_Z15_TUNE 373 def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT 374 375choice 376 prompt "Tune code generation" 377 default TUNE_DEFAULT 378 help 379 Cause the compiler to tune (-mtune) the generated code for a machine. 380 This will make the code run faster on the selected machine but 381 somewhat slower on other machines. 382 This option only changes how the compiler emits instructions, not the 383 selection of instructions itself, so the resulting kernel will run on 384 all other machines. 385 386config TUNE_DEFAULT 387 bool "Default" 388 help 389 Tune the generated code for the target processor for which the kernel 390 will be compiled. 391 392config TUNE_Z900 393 bool "IBM zSeries model z800 and z900" 394 depends on $(cc-option,-mtune=z900) 395 396config TUNE_Z990 397 bool "IBM zSeries model z890 and z990" 398 depends on $(cc-option,-mtune=z990) 399 400config TUNE_Z9_109 401 bool "IBM System z9" 402 depends on $(cc-option,-mtune=z9-109) 403 404config TUNE_Z10 405 bool "IBM System z10" 406 depends on $(cc-option,-mtune=z10) 407 408config TUNE_Z196 409 bool "IBM zEnterprise 114 and 196" 410 depends on $(cc-option,-mtune=z196) 411 412config TUNE_ZEC12 413 bool "IBM zBC12 and zEC12" 414 depends on $(cc-option,-mtune=zEC12) 415 416config TUNE_Z13 417 bool "IBM z13s and z13" 418 depends on $(cc-option,-mtune=z13) 419 420config TUNE_Z14 421 bool "IBM z14 ZR1 and z14" 422 depends on $(cc-option,-mtune=z14) 423 424config TUNE_Z15 425 bool "IBM z15" 426 depends on $(cc-option,-mtune=z15) 427 428endchoice 429 430config 64BIT 431 def_bool y 432 433config COMPAT 434 def_bool y 435 prompt "Kernel support for 31 bit emulation" 436 select ARCH_WANT_OLD_COMPAT_IPC 437 select COMPAT_OLD_SIGACTION 438 select HAVE_UID16 439 depends on MULTIUSER 440 depends on !CC_IS_CLANG 441 help 442 Select this option if you want to enable your system kernel to 443 handle system-calls from ELF binaries for 31 bit ESA. This option 444 (and some other stuff like libraries and such) is needed for 445 executing 31 bit applications. It is safe to say "Y". 446 447config SYSVIPC_COMPAT 448 def_bool y if COMPAT && SYSVIPC 449 450config SMP 451 def_bool y 452 453config NR_CPUS 454 int "Maximum number of CPUs (2-512)" 455 range 2 512 456 default "64" 457 help 458 This allows you to specify the maximum number of CPUs which this 459 kernel will support. The maximum supported value is 512 and the 460 minimum value which makes sense is 2. 461 462 This is purely to save memory - each supported CPU adds 463 approximately sixteen kilobytes to the kernel image. 464 465config HOTPLUG_CPU 466 def_bool y 467 468config NUMA 469 bool "NUMA support" 470 depends on SCHED_TOPOLOGY 471 default n 472 help 473 Enable NUMA support 474 475 This option adds NUMA support to the kernel. 476 477config NODES_SHIFT 478 int 479 depends on NUMA 480 default "1" 481 482config SCHED_SMT 483 def_bool n 484 485config SCHED_MC 486 def_bool n 487 488config SCHED_BOOK 489 def_bool n 490 491config SCHED_DRAWER 492 def_bool n 493 494config SCHED_TOPOLOGY 495 def_bool y 496 prompt "Topology scheduler support" 497 select SCHED_SMT 498 select SCHED_MC 499 select SCHED_BOOK 500 select SCHED_DRAWER 501 help 502 Topology scheduler support improves the CPU scheduler's decision 503 making when dealing with machines that have multi-threading, 504 multiple cores or multiple books. 505 506source "kernel/Kconfig.hz" 507 508config KEXEC 509 def_bool y 510 select KEXEC_CORE 511 512config KEXEC_FILE 513 bool "kexec file based system call" 514 select KEXEC_CORE 515 select BUILD_BIN2C 516 depends on CRYPTO 517 depends on CRYPTO_SHA256 518 depends on CRYPTO_SHA256_S390 519 help 520 Enable the kexec file based system call. In contrast to the normal 521 kexec system call this system call takes file descriptors for the 522 kernel and initramfs as arguments. 523 524config ARCH_HAS_KEXEC_PURGATORY 525 def_bool y 526 depends on KEXEC_FILE 527 528config KEXEC_SIG 529 bool "Verify kernel signature during kexec_file_load() syscall" 530 depends on KEXEC_FILE && MODULE_SIG_FORMAT 531 help 532 This option makes kernel signature verification mandatory for 533 the kexec_file_load() syscall. 534 535 In addition to that option, you need to enable signature 536 verification for the corresponding kernel image type being 537 loaded in order for this to work. 538 539config ARCH_RANDOM 540 def_bool y 541 prompt "s390 architectural random number generation API" 542 help 543 Enable the s390 architectural random number generation API 544 to provide random data for all consumers within the Linux 545 kernel. 546 547 When enabled the arch_random_* functions declared in linux/random.h 548 are implemented. The implementation is based on the s390 CPACF 549 instruction subfunction TRNG which provides a real true random 550 number generator. 551 552 If unsure, say Y. 553 554config KERNEL_NOBP 555 def_bool n 556 prompt "Enable modified branch prediction for the kernel by default" 557 help 558 If this option is selected the kernel will switch to a modified 559 branch prediction mode if the firmware interface is available. 560 The modified branch prediction mode improves the behaviour in 561 regard to speculative execution. 562 563 With the option enabled the kernel parameter "nobp=0" or "nospec" 564 can be used to run the kernel in the normal branch prediction mode. 565 566 With the option disabled the modified branch prediction mode is 567 enabled with the "nobp=1" kernel parameter. 568 569 If unsure, say N. 570 571config EXPOLINE 572 def_bool n 573 prompt "Avoid speculative indirect branches in the kernel" 574 help 575 Compile the kernel with the expoline compiler options to guard 576 against kernel-to-user data leaks by avoiding speculative indirect 577 branches. 578 Requires a compiler with -mindirect-branch=thunk support for full 579 protection. The kernel may run slower. 580 581 If unsure, say N. 582 583choice 584 prompt "Expoline default" 585 depends on EXPOLINE 586 default EXPOLINE_FULL 587 588config EXPOLINE_OFF 589 bool "spectre_v2=off" 590 591config EXPOLINE_AUTO 592 bool "spectre_v2=auto" 593 594config EXPOLINE_FULL 595 bool "spectre_v2=on" 596 597endchoice 598 599config RELOCATABLE 600 bool "Build a relocatable kernel" 601 select MODULE_REL_CRCS if MODVERSIONS 602 default y 603 help 604 This builds a kernel image that retains relocation information 605 so it can be loaded at an arbitrary address. 606 The kernel is linked as a position-independent executable (PIE) 607 and contains dynamic relocations which are processed early in the 608 bootup process. 609 The relocations make the kernel image about 15% larger (compressed 610 10%), but are discarded at runtime. 611 612config RANDOMIZE_BASE 613 bool "Randomize the address of the kernel image (KASLR)" 614 depends on RELOCATABLE 615 default y 616 help 617 In support of Kernel Address Space Layout Randomization (KASLR), 618 this randomizes the address at which the kernel image is loaded, 619 as a security feature that deters exploit attempts relying on 620 knowledge of the location of kernel internals. 621 622endmenu 623 624menu "Memory setup" 625 626config ARCH_SPARSEMEM_ENABLE 627 def_bool y 628 select SPARSEMEM_VMEMMAP_ENABLE 629 select SPARSEMEM_VMEMMAP 630 631config ARCH_SPARSEMEM_DEFAULT 632 def_bool y 633 634config MAX_PHYSMEM_BITS 635 int "Maximum size of supported physical memory in bits (42-53)" 636 range 42 53 637 default "46" 638 help 639 This option specifies the maximum supported size of physical memory 640 in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB). 641 Increasing the number of bits also increases the kernel image size. 642 By default 46 bits (64TB) are supported. 643 644config PACK_STACK 645 def_bool y 646 prompt "Pack kernel stack" 647 help 648 This option enables the compiler option -mkernel-backchain if it 649 is available. If the option is available the compiler supports 650 the new stack layout which dramatically reduces the minimum stack 651 frame size. With an old compiler a non-leaf function needs a 652 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With 653 -mkernel-backchain the minimum size drops to 16 byte on 31 bit 654 and 24 byte on 64 bit. 655 656 Say Y if you are unsure. 657 658config CHECK_STACK 659 def_bool y 660 depends on !VMAP_STACK 661 prompt "Detect kernel stack overflow" 662 help 663 This option enables the compiler option -mstack-guard and 664 -mstack-size if they are available. If the compiler supports them 665 it will emit additional code to each function prolog to trigger 666 an illegal operation if the kernel stack is about to overflow. 667 668 Say N if you are unsure. 669 670config STACK_GUARD 671 int "Size of the guard area (128-1024)" 672 range 128 1024 673 depends on CHECK_STACK 674 default "256" 675 help 676 This allows you to specify the size of the guard area at the lower 677 end of the kernel stack. If the kernel stack points into the guard 678 area on function entry an illegal operation is triggered. The size 679 needs to be a power of 2. Please keep in mind that the size of an 680 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit. 681 The minimum size for the stack guard should be 256 for 31 bit and 682 512 for 64 bit. 683 684config WARN_DYNAMIC_STACK 685 def_bool n 686 prompt "Emit compiler warnings for function with dynamic stack usage" 687 help 688 This option enables the compiler option -mwarn-dynamicstack. If the 689 compiler supports this options generates warnings for functions 690 that dynamically allocate stack space using alloca. 691 692 Say N if you are unsure. 693 694endmenu 695 696menu "I/O subsystem" 697 698config QDIO 699 def_tristate y 700 prompt "QDIO support" 701 help 702 This driver provides the Queued Direct I/O base support for 703 IBM System z. 704 705 To compile this driver as a module, choose M here: the 706 module will be called qdio. 707 708 If unsure, say Y. 709 710if PCI 711 712config PCI_NR_FUNCTIONS 713 int "Maximum number of PCI functions (1-4096)" 714 range 1 4096 715 default "512" 716 help 717 This allows you to specify the maximum number of PCI functions which 718 this kernel will support. 719 720endif # PCI 721 722config HAS_IOMEM 723 def_bool PCI 724 725config CHSC_SCH 726 def_tristate m 727 prompt "Support for CHSC subchannels" 728 help 729 This driver allows usage of CHSC subchannels. A CHSC subchannel 730 is usually present on LPAR only. 731 The driver creates a device /dev/chsc, which may be used to 732 obtain I/O configuration information about the machine and 733 to issue asynchronous chsc commands (DANGEROUS). 734 You will usually only want to use this interface on a special 735 LPAR designated for system management. 736 737 To compile this driver as a module, choose M here: the 738 module will be called chsc_sch. 739 740 If unsure, say N. 741 742config SCM_BUS 743 def_bool y 744 prompt "SCM bus driver" 745 help 746 Bus driver for Storage Class Memory. 747 748config EADM_SCH 749 def_tristate m 750 prompt "Support for EADM subchannels" 751 depends on SCM_BUS 752 help 753 This driver allows usage of EADM subchannels. EADM subchannels act 754 as a communication vehicle for SCM increments. 755 756 To compile this driver as a module, choose M here: the 757 module will be called eadm_sch. 758 759config VFIO_CCW 760 def_tristate n 761 prompt "Support for VFIO-CCW subchannels" 762 depends on S390_CCW_IOMMU && VFIO_MDEV 763 help 764 This driver allows usage of I/O subchannels via VFIO-CCW. 765 766 To compile this driver as a module, choose M here: the 767 module will be called vfio_ccw. 768 769config VFIO_AP 770 def_tristate n 771 prompt "VFIO support for AP devices" 772 depends on S390_AP_IOMMU && VFIO_MDEV && KVM 773 depends on ZCRYPT 774 help 775 This driver grants access to Adjunct Processor (AP) devices 776 via the VFIO mediated device interface. 777 778 To compile this driver as a module, choose M here: the module 779 will be called vfio_ap. 780 781endmenu 782 783menu "Dump support" 784 785config CRASH_DUMP 786 bool "kernel crash dumps" 787 select KEXEC 788 help 789 Generate crash dump after being started by kexec. 790 Crash dump kernels are loaded in the main kernel with kexec-tools 791 into a specially reserved region and then later executed after 792 a crash by kdump/kexec. 793 Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this. 794 This option also enables s390 zfcpdump. 795 See also <file:Documentation/s390/zfcpdump.rst> 796 797endmenu 798 799config CCW 800 def_bool y 801 802config HAVE_PNETID 803 tristate 804 default (SMC || CCWGROUP) 805 806menu "Virtualization" 807 808config PROTECTED_VIRTUALIZATION_GUEST 809 def_bool n 810 prompt "Protected virtualization guest support" 811 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 812 help 813 Select this option, if you want to be able to run this 814 kernel as a protected virtualization KVM guest. 815 Protected virtualization capable machines have a mini hypervisor 816 located at machine level (an ultravisor). With help of the 817 Ultravisor, KVM will be able to run "protected" VMs, special 818 VMs whose memory and management data are unavailable to KVM. 819 820config PFAULT 821 def_bool y 822 prompt "Pseudo page fault support" 823 help 824 Select this option, if you want to use PFAULT pseudo page fault 825 handling under VM. If running native or in LPAR, this option 826 has no effect. If your VM does not support PFAULT, PAGEEX 827 pseudo page fault handling will be used. 828 Note that VM 4.2 supports PFAULT but has a bug in its 829 implementation that causes some problems. 830 Everybody who wants to run Linux under VM != VM4.2 should select 831 this option. 832 833config CMM 834 def_tristate n 835 prompt "Cooperative memory management" 836 help 837 Select this option, if you want to enable the kernel interface 838 to reduce the memory size of the system. This is accomplished 839 by allocating pages of memory and put them "on hold". This only 840 makes sense for a system running under VM where the unused pages 841 will be reused by VM for other guest systems. The interface 842 allows an external monitor to balance memory of many systems. 843 Everybody who wants to run Linux under VM should select this 844 option. 845 846config CMM_IUCV 847 def_bool y 848 prompt "IUCV special message interface to cooperative memory management" 849 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV) 850 help 851 Select this option to enable the special message interface to 852 the cooperative memory management. 853 854config APPLDATA_BASE 855 def_bool n 856 prompt "Linux - VM Monitor Stream, base infrastructure" 857 depends on PROC_SYSCTL 858 help 859 This provides a kernel interface for creating and updating z/VM APPLDATA 860 monitor records. The monitor records are updated at certain time 861 intervals, once the timer is started. 862 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer, 863 i.e. enables or disables monitoring on the Linux side. 864 A custom interval value (in seconds) can be written to 865 /proc/appldata/interval. 866 867 Defaults are 60 seconds interval and timer off. 868 The /proc entries can also be read from, showing the current settings. 869 870config APPLDATA_MEM 871 def_tristate m 872 prompt "Monitor memory management statistics" 873 depends on APPLDATA_BASE && VM_EVENT_COUNTERS 874 help 875 This provides memory management related data to the Linux - VM Monitor 876 Stream, like paging/swapping rate, memory utilisation, etc. 877 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM 878 APPLDATA monitor record, i.e. enables or disables monitoring this record 879 on the z/VM side. 880 881 Default is disabled. 882 The /proc entry can also be read from, showing the current settings. 883 884 This can also be compiled as a module, which will be called 885 appldata_mem.o. 886 887config APPLDATA_OS 888 def_tristate m 889 prompt "Monitor OS statistics" 890 depends on APPLDATA_BASE 891 help 892 This provides OS related data to the Linux - VM Monitor Stream, like 893 CPU utilisation, etc. 894 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM 895 APPLDATA monitor record, i.e. enables or disables monitoring this record 896 on the z/VM side. 897 898 Default is disabled. 899 This can also be compiled as a module, which will be called 900 appldata_os.o. 901 902config APPLDATA_NET_SUM 903 def_tristate m 904 prompt "Monitor overall network statistics" 905 depends on APPLDATA_BASE && NET 906 help 907 This provides network related data to the Linux - VM Monitor Stream, 908 currently there is only a total sum of network I/O statistics, no 909 per-interface data. 910 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM 911 APPLDATA monitor record, i.e. enables or disables monitoring this record 912 on the z/VM side. 913 914 Default is disabled. 915 This can also be compiled as a module, which will be called 916 appldata_net_sum.o. 917 918config S390_HYPFS_FS 919 def_bool y 920 prompt "s390 hypervisor file system support" 921 select SYS_HYPERVISOR 922 help 923 This is a virtual file system intended to provide accounting 924 information in an s390 hypervisor environment. 925 926source "arch/s390/kvm/Kconfig" 927 928config S390_GUEST 929 def_bool y 930 prompt "s390 support for virtio devices" 931 select TTY 932 select VIRTUALIZATION 933 select VIRTIO 934 help 935 Enabling this option adds support for virtio based paravirtual device 936 drivers on s390. 937 938 Select this option if you want to run the kernel as a guest under 939 the KVM hypervisor. 940 941endmenu 942 943menu "Selftests" 944 945config S390_UNWIND_SELFTEST 946 def_tristate n 947 prompt "Test unwind functions" 948 help 949 This option enables s390 specific stack unwinder testing kernel 950 module. This option is not useful for distributions or general 951 kernels, but only for kernel developers working on architecture code. 952 953 Say N if you are unsure. 954 955endmenu 956