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 0x1C000000000000 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_HUGETLBFS 114 select ARCH_SUPPORTS_NUMA_BALANCING 115 select ARCH_USE_BUILTIN_BSWAP 116 select ARCH_USE_CMPXCHG_LOCKREF 117 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 118 select ARCH_WANTS_NO_INSTR 119 select ARCH_WANT_DEFAULT_BPF_JIT 120 select ARCH_WANT_IPC_PARSE_VERSION 121 select BUILDTIME_TABLE_SORT 122 select CLONE_BACKWARDS2 123 select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES 124 select DMA_OPS if PCI 125 select DYNAMIC_FTRACE if FUNCTION_TRACER 126 select GENERIC_ALLOCATOR 127 select GENERIC_CPU_AUTOPROBE 128 select GENERIC_CPU_VULNERABILITIES 129 select GENERIC_ENTRY 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_KCSAN 142 select HAVE_ARCH_KFENCE 143 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 144 select HAVE_ARCH_SECCOMP_FILTER 145 select HAVE_ARCH_SOFT_DIRTY 146 select HAVE_ARCH_TRACEHOOK 147 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 148 select HAVE_ARCH_VMAP_STACK 149 select HAVE_ASM_MODVERSIONS 150 select HAVE_CMPXCHG_DOUBLE 151 select HAVE_CMPXCHG_LOCAL 152 select HAVE_DEBUG_KMEMLEAK 153 select HAVE_DMA_CONTIGUOUS 154 select HAVE_DYNAMIC_FTRACE 155 select HAVE_DYNAMIC_FTRACE_WITH_ARGS 156 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 157 select HAVE_DYNAMIC_FTRACE_WITH_REGS 158 select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES 159 select HAVE_EFFICIENT_UNALIGNED_ACCESS 160 select HAVE_FAST_GUP 161 select HAVE_FENTRY 162 select HAVE_FTRACE_MCOUNT_RECORD 163 select HAVE_FUNCTION_ARG_ACCESS_API 164 select HAVE_FUNCTION_ERROR_INJECTION 165 select HAVE_FUNCTION_GRAPH_TRACER 166 select HAVE_FUNCTION_TRACER 167 select HAVE_GCC_PLUGINS 168 select HAVE_GENERIC_VDSO 169 select HAVE_IOREMAP_PROT if PCI 170 select HAVE_KERNEL_BZIP2 171 select HAVE_KERNEL_GZIP 172 select HAVE_KERNEL_LZ4 173 select HAVE_KERNEL_LZMA 174 select HAVE_KERNEL_LZO 175 select HAVE_KERNEL_UNCOMPRESSED 176 select HAVE_KERNEL_XZ 177 select HAVE_KERNEL_ZSTD 178 select HAVE_KPROBES 179 select HAVE_KPROBES_ON_FTRACE 180 select HAVE_KRETPROBES 181 select HAVE_KVM 182 select HAVE_LIVEPATCH 183 select HAVE_MEMBLOCK_PHYS_MAP 184 select HAVE_MOD_ARCH_SPECIFIC 185 select HAVE_NMI 186 select HAVE_NOP_MCOUNT 187 select HAVE_PCI 188 select HAVE_PERF_EVENTS 189 select HAVE_PERF_REGS 190 select HAVE_PERF_USER_STACK_DUMP 191 select HAVE_REGS_AND_STACK_ACCESS_API 192 select HAVE_RELIABLE_STACKTRACE 193 select HAVE_RSEQ 194 select HAVE_SAMPLE_FTRACE_DIRECT 195 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI 196 select HAVE_SOFTIRQ_ON_OWN_STACK 197 select HAVE_SYSCALL_TRACEPOINTS 198 select HAVE_VIRT_CPU_ACCOUNTING 199 select HAVE_VIRT_CPU_ACCOUNTING_IDLE 200 select IOMMU_HELPER if PCI 201 select IOMMU_SUPPORT if PCI 202 select MMU_GATHER_NO_GATHER 203 select MMU_GATHER_RCU_TABLE_FREE 204 select MODULES_USE_ELF_RELA 205 select NEED_DMA_MAP_STATE if PCI 206 select NEED_SG_DMA_LENGTH if PCI 207 select OLD_SIGACTION 208 select OLD_SIGSUSPEND3 209 select PCI_DOMAINS if PCI 210 select PCI_MSI if PCI 211 select PCI_MSI_ARCH_FALLBACKS if PCI_MSI 212 select SPARSE_IRQ 213 select SWIOTLB 214 select SYSCTL_EXCEPTION_TRACE 215 select THREAD_INFO_IN_TASK 216 select TRACE_IRQFLAGS_SUPPORT 217 select TTY 218 select VIRT_CPU_ACCOUNTING 219 select ZONE_DMA 220 # Note: keep the above list sorted alphabetically 221 222config SCHED_OMIT_FRAME_POINTER 223 def_bool y 224 225config PGTABLE_LEVELS 226 int 227 default 5 228 229source "kernel/livepatch/Kconfig" 230 231menu "Processor type and features" 232 233config HAVE_MARCH_Z900_FEATURES 234 def_bool n 235 236config HAVE_MARCH_Z990_FEATURES 237 def_bool n 238 select HAVE_MARCH_Z900_FEATURES 239 240config HAVE_MARCH_Z9_109_FEATURES 241 def_bool n 242 select HAVE_MARCH_Z990_FEATURES 243 244config HAVE_MARCH_Z10_FEATURES 245 def_bool n 246 select HAVE_MARCH_Z9_109_FEATURES 247 248config HAVE_MARCH_Z196_FEATURES 249 def_bool n 250 select HAVE_MARCH_Z10_FEATURES 251 252config HAVE_MARCH_ZEC12_FEATURES 253 def_bool n 254 select HAVE_MARCH_Z196_FEATURES 255 256config HAVE_MARCH_Z13_FEATURES 257 def_bool n 258 select HAVE_MARCH_ZEC12_FEATURES 259 260config HAVE_MARCH_Z14_FEATURES 261 def_bool n 262 select HAVE_MARCH_Z13_FEATURES 263 264config HAVE_MARCH_Z15_FEATURES 265 def_bool n 266 select HAVE_MARCH_Z14_FEATURES 267 268choice 269 prompt "Processor type" 270 default MARCH_Z196 271 272config MARCH_Z900 273 bool "IBM zSeries model z800 and z900" 274 select HAVE_MARCH_Z900_FEATURES 275 depends on $(cc-option,-march=z900) 276 help 277 Select this to enable optimizations for model z800/z900 (2064 and 278 2066 series). This will enable some optimizations that are not 279 available on older ESA/390 (31 Bit) only CPUs. 280 281config MARCH_Z990 282 bool "IBM zSeries model z890 and z990" 283 select HAVE_MARCH_Z990_FEATURES 284 depends on $(cc-option,-march=z990) 285 help 286 Select this to enable optimizations for model z890/z990 (2084 and 287 2086 series). The kernel will be slightly faster but will not work 288 on older machines. 289 290config MARCH_Z9_109 291 bool "IBM System z9" 292 select HAVE_MARCH_Z9_109_FEATURES 293 depends on $(cc-option,-march=z9-109) 294 help 295 Select this to enable optimizations for IBM System z9 (2094 and 296 2096 series). The kernel will be slightly faster but will not work 297 on older machines. 298 299config MARCH_Z10 300 bool "IBM System z10" 301 select HAVE_MARCH_Z10_FEATURES 302 depends on $(cc-option,-march=z10) 303 help 304 Select this to enable optimizations for IBM System z10 (2097 and 305 2098 series). The kernel will be slightly faster but will not work 306 on older machines. 307 308config MARCH_Z196 309 bool "IBM zEnterprise 114 and 196" 310 select HAVE_MARCH_Z196_FEATURES 311 depends on $(cc-option,-march=z196) 312 help 313 Select this to enable optimizations for IBM zEnterprise 114 and 196 314 (2818 and 2817 series). The kernel will be slightly faster but will 315 not work on older machines. 316 317config MARCH_ZEC12 318 bool "IBM zBC12 and zEC12" 319 select HAVE_MARCH_ZEC12_FEATURES 320 depends on $(cc-option,-march=zEC12) 321 help 322 Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and 323 2827 series). The kernel will be slightly faster but will not work on 324 older machines. 325 326config MARCH_Z13 327 bool "IBM z13s and z13" 328 select HAVE_MARCH_Z13_FEATURES 329 depends on $(cc-option,-march=z13) 330 help 331 Select this to enable optimizations for IBM z13s and z13 (2965 and 332 2964 series). The kernel will be slightly faster but will not work on 333 older machines. 334 335config MARCH_Z14 336 bool "IBM z14 ZR1 and z14" 337 select HAVE_MARCH_Z14_FEATURES 338 depends on $(cc-option,-march=z14) 339 help 340 Select this to enable optimizations for IBM z14 ZR1 and z14 (3907 341 and 3906 series). The kernel will be slightly faster but will not 342 work on older machines. 343 344config MARCH_Z15 345 bool "IBM z15" 346 select HAVE_MARCH_Z15_FEATURES 347 depends on $(cc-option,-march=z15) 348 help 349 Select this to enable optimizations for IBM z15 (8562 350 and 8561 series). The kernel will be slightly faster but will not 351 work on older machines. 352 353endchoice 354 355config MARCH_Z900_TUNE 356 def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT 357 358config MARCH_Z990_TUNE 359 def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT 360 361config MARCH_Z9_109_TUNE 362 def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT 363 364config MARCH_Z10_TUNE 365 def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT 366 367config MARCH_Z196_TUNE 368 def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT 369 370config MARCH_ZEC12_TUNE 371 def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT 372 373config MARCH_Z13_TUNE 374 def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT 375 376config MARCH_Z14_TUNE 377 def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT 378 379config MARCH_Z15_TUNE 380 def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT 381 382choice 383 prompt "Tune code generation" 384 default TUNE_DEFAULT 385 help 386 Cause the compiler to tune (-mtune) the generated code for a machine. 387 This will make the code run faster on the selected machine but 388 somewhat slower on other machines. 389 This option only changes how the compiler emits instructions, not the 390 selection of instructions itself, so the resulting kernel will run on 391 all other machines. 392 393config TUNE_DEFAULT 394 bool "Default" 395 help 396 Tune the generated code for the target processor for which the kernel 397 will be compiled. 398 399config TUNE_Z900 400 bool "IBM zSeries model z800 and z900" 401 depends on $(cc-option,-mtune=z900) 402 403config TUNE_Z990 404 bool "IBM zSeries model z890 and z990" 405 depends on $(cc-option,-mtune=z990) 406 407config TUNE_Z9_109 408 bool "IBM System z9" 409 depends on $(cc-option,-mtune=z9-109) 410 411config TUNE_Z10 412 bool "IBM System z10" 413 depends on $(cc-option,-mtune=z10) 414 415config TUNE_Z196 416 bool "IBM zEnterprise 114 and 196" 417 depends on $(cc-option,-mtune=z196) 418 419config TUNE_ZEC12 420 bool "IBM zBC12 and zEC12" 421 depends on $(cc-option,-mtune=zEC12) 422 423config TUNE_Z13 424 bool "IBM z13s and z13" 425 depends on $(cc-option,-mtune=z13) 426 427config TUNE_Z14 428 bool "IBM z14 ZR1 and z14" 429 depends on $(cc-option,-mtune=z14) 430 431config TUNE_Z15 432 bool "IBM z15" 433 depends on $(cc-option,-mtune=z15) 434 435endchoice 436 437config 64BIT 438 def_bool y 439 440config COMMAND_LINE_SIZE 441 int "Maximum size of kernel command line" 442 default 4096 443 range 896 1048576 444 help 445 This allows you to specify the maximum length of the kernel command 446 line. 447 448config COMPAT 449 def_bool y 450 prompt "Kernel support for 31 bit emulation" 451 select ARCH_WANT_OLD_COMPAT_IPC 452 select COMPAT_OLD_SIGACTION 453 select HAVE_UID16 454 depends on MULTIUSER 455 depends on !CC_IS_CLANG 456 help 457 Select this option if you want to enable your system kernel to 458 handle system-calls from ELF binaries for 31 bit ESA. This option 459 (and some other stuff like libraries and such) is needed for 460 executing 31 bit applications. It is safe to say "Y". 461 462config SYSVIPC_COMPAT 463 def_bool y if COMPAT && SYSVIPC 464 465config SMP 466 def_bool y 467 468config NR_CPUS 469 int "Maximum number of CPUs (2-512)" 470 range 2 512 471 default "64" 472 help 473 This allows you to specify the maximum number of CPUs which this 474 kernel will support. The maximum supported value is 512 and the 475 minimum value which makes sense is 2. 476 477 This is purely to save memory - each supported CPU adds 478 approximately sixteen kilobytes to the kernel image. 479 480config HOTPLUG_CPU 481 def_bool y 482 483config NUMA 484 bool "NUMA support" 485 depends on SCHED_TOPOLOGY 486 default n 487 help 488 Enable NUMA support 489 490 This option adds NUMA support to the kernel. 491 492config NODES_SHIFT 493 int 494 depends on NUMA 495 default "1" 496 497config SCHED_SMT 498 def_bool n 499 500config SCHED_MC 501 def_bool n 502 503config SCHED_BOOK 504 def_bool n 505 506config SCHED_DRAWER 507 def_bool n 508 509config SCHED_TOPOLOGY 510 def_bool y 511 prompt "Topology scheduler support" 512 select SCHED_SMT 513 select SCHED_MC 514 select SCHED_BOOK 515 select SCHED_DRAWER 516 help 517 Topology scheduler support improves the CPU scheduler's decision 518 making when dealing with machines that have multi-threading, 519 multiple cores or multiple books. 520 521source "kernel/Kconfig.hz" 522 523config KEXEC 524 def_bool y 525 select KEXEC_CORE 526 527config KEXEC_FILE 528 bool "kexec file based system call" 529 select KEXEC_CORE 530 select BUILD_BIN2C 531 depends on CRYPTO 532 depends on CRYPTO_SHA256 533 depends on CRYPTO_SHA256_S390 534 help 535 Enable the kexec file based system call. In contrast to the normal 536 kexec system call this system call takes file descriptors for the 537 kernel and initramfs as arguments. 538 539config ARCH_HAS_KEXEC_PURGATORY 540 def_bool y 541 depends on KEXEC_FILE 542 543config KEXEC_SIG 544 bool "Verify kernel signature during kexec_file_load() syscall" 545 depends on KEXEC_FILE && MODULE_SIG_FORMAT 546 help 547 This option makes kernel signature verification mandatory for 548 the kexec_file_load() syscall. 549 550 In addition to that option, you need to enable signature 551 verification for the corresponding kernel image type being 552 loaded in order for this to work. 553 554config ARCH_RANDOM 555 def_bool y 556 prompt "s390 architectural random number generation API" 557 help 558 Enable the s390 architectural random number generation API 559 to provide random data for all consumers within the Linux 560 kernel. 561 562 When enabled the arch_random_* functions declared in linux/random.h 563 are implemented. The implementation is based on the s390 CPACF 564 instruction subfunction TRNG which provides a real true random 565 number generator. 566 567 If unsure, say Y. 568 569config KERNEL_NOBP 570 def_bool n 571 prompt "Enable modified branch prediction for the kernel by default" 572 help 573 If this option is selected the kernel will switch to a modified 574 branch prediction mode if the firmware interface is available. 575 The modified branch prediction mode improves the behaviour in 576 regard to speculative execution. 577 578 With the option enabled the kernel parameter "nobp=0" or "nospec" 579 can be used to run the kernel in the normal branch prediction mode. 580 581 With the option disabled the modified branch prediction mode is 582 enabled with the "nobp=1" kernel parameter. 583 584 If unsure, say N. 585 586config EXPOLINE 587 def_bool n 588 prompt "Avoid speculative indirect branches in the kernel" 589 help 590 Compile the kernel with the expoline compiler options to guard 591 against kernel-to-user data leaks by avoiding speculative indirect 592 branches. 593 Requires a compiler with -mindirect-branch=thunk support for full 594 protection. The kernel may run slower. 595 596 If unsure, say N. 597 598choice 599 prompt "Expoline default" 600 depends on EXPOLINE 601 default EXPOLINE_FULL 602 603config EXPOLINE_OFF 604 bool "spectre_v2=off" 605 606config EXPOLINE_AUTO 607 bool "spectre_v2=auto" 608 609config EXPOLINE_FULL 610 bool "spectre_v2=on" 611 612endchoice 613 614config RELOCATABLE 615 bool "Build a relocatable kernel" 616 select MODULE_REL_CRCS if MODVERSIONS 617 default y 618 help 619 This builds a kernel image that retains relocation information 620 so it can be loaded at an arbitrary address. 621 The kernel is linked as a position-independent executable (PIE) 622 and contains dynamic relocations which are processed early in the 623 bootup process. 624 The relocations make the kernel image about 15% larger (compressed 625 10%), but are discarded at runtime. 626 627config RANDOMIZE_BASE 628 bool "Randomize the address of the kernel image (KASLR)" 629 depends on RELOCATABLE 630 default y 631 help 632 In support of Kernel Address Space Layout Randomization (KASLR), 633 this randomizes the address at which the kernel image is loaded, 634 as a security feature that deters exploit attempts relying on 635 knowledge of the location of kernel internals. 636 637endmenu 638 639menu "Memory setup" 640 641config ARCH_SPARSEMEM_ENABLE 642 def_bool y 643 select SPARSEMEM_VMEMMAP_ENABLE 644 select SPARSEMEM_VMEMMAP 645 646config ARCH_SPARSEMEM_DEFAULT 647 def_bool y 648 649config MAX_PHYSMEM_BITS 650 int "Maximum size of supported physical memory in bits (42-53)" 651 range 42 53 652 default "46" 653 help 654 This option specifies the maximum supported size of physical memory 655 in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB). 656 Increasing the number of bits also increases the kernel image size. 657 By default 46 bits (64TB) are supported. 658 659config PACK_STACK 660 def_bool y 661 prompt "Pack kernel stack" 662 help 663 This option enables the compiler option -mkernel-backchain if it 664 is available. If the option is available the compiler supports 665 the new stack layout which dramatically reduces the minimum stack 666 frame size. With an old compiler a non-leaf function needs a 667 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With 668 -mkernel-backchain the minimum size drops to 16 byte on 31 bit 669 and 24 byte on 64 bit. 670 671 Say Y if you are unsure. 672 673config CHECK_STACK 674 def_bool y 675 depends on !VMAP_STACK 676 prompt "Detect kernel stack overflow" 677 help 678 This option enables the compiler option -mstack-guard and 679 -mstack-size if they are available. If the compiler supports them 680 it will emit additional code to each function prolog to trigger 681 an illegal operation if the kernel stack is about to overflow. 682 683 Say N if you are unsure. 684 685config STACK_GUARD 686 int "Size of the guard area (128-1024)" 687 range 128 1024 688 depends on CHECK_STACK 689 default "256" 690 help 691 This allows you to specify the size of the guard area at the lower 692 end of the kernel stack. If the kernel stack points into the guard 693 area on function entry an illegal operation is triggered. The size 694 needs to be a power of 2. Please keep in mind that the size of an 695 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit. 696 The minimum size for the stack guard should be 256 for 31 bit and 697 512 for 64 bit. 698 699endmenu 700 701menu "I/O subsystem" 702 703config QDIO 704 def_tristate y 705 prompt "QDIO support" 706 help 707 This driver provides the Queued Direct I/O base support for 708 IBM System z. 709 710 To compile this driver as a module, choose M here: the 711 module will be called qdio. 712 713 If unsure, say Y. 714 715if PCI 716 717config PCI_NR_FUNCTIONS 718 int "Maximum number of PCI functions (1-4096)" 719 range 1 4096 720 default "512" 721 help 722 This allows you to specify the maximum number of PCI functions which 723 this kernel will support. 724 725endif # PCI 726 727config HAS_IOMEM 728 def_bool PCI 729 730config CHSC_SCH 731 def_tristate m 732 prompt "Support for CHSC subchannels" 733 help 734 This driver allows usage of CHSC subchannels. A CHSC subchannel 735 is usually present on LPAR only. 736 The driver creates a device /dev/chsc, which may be used to 737 obtain I/O configuration information about the machine and 738 to issue asynchronous chsc commands (DANGEROUS). 739 You will usually only want to use this interface on a special 740 LPAR designated for system management. 741 742 To compile this driver as a module, choose M here: the 743 module will be called chsc_sch. 744 745 If unsure, say N. 746 747config SCM_BUS 748 def_bool y 749 prompt "SCM bus driver" 750 help 751 Bus driver for Storage Class Memory. 752 753config EADM_SCH 754 def_tristate m 755 prompt "Support for EADM subchannels" 756 depends on SCM_BUS 757 help 758 This driver allows usage of EADM subchannels. EADM subchannels act 759 as a communication vehicle for SCM increments. 760 761 To compile this driver as a module, choose M here: the 762 module will be called eadm_sch. 763 764config VFIO_CCW 765 def_tristate n 766 prompt "Support for VFIO-CCW subchannels" 767 depends on S390_CCW_IOMMU && VFIO_MDEV 768 help 769 This driver allows usage of I/O subchannels via VFIO-CCW. 770 771 To compile this driver as a module, choose M here: the 772 module will be called vfio_ccw. 773 774config VFIO_AP 775 def_tristate n 776 prompt "VFIO support for AP devices" 777 depends on S390_AP_IOMMU && VFIO_MDEV && KVM 778 depends on ZCRYPT 779 help 780 This driver grants access to Adjunct Processor (AP) devices 781 via the VFIO mediated device interface. 782 783 To compile this driver as a module, choose M here: the module 784 will be called vfio_ap. 785 786endmenu 787 788menu "Dump support" 789 790config CRASH_DUMP 791 bool "kernel crash dumps" 792 select KEXEC 793 help 794 Generate crash dump after being started by kexec. 795 Crash dump kernels are loaded in the main kernel with kexec-tools 796 into a specially reserved region and then later executed after 797 a crash by kdump/kexec. 798 Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this. 799 This option also enables s390 zfcpdump. 800 See also <file:Documentation/s390/zfcpdump.rst> 801 802endmenu 803 804config CCW 805 def_bool y 806 807config HAVE_PNETID 808 tristate 809 default (SMC || CCWGROUP) 810 811menu "Virtualization" 812 813config PROTECTED_VIRTUALIZATION_GUEST 814 def_bool n 815 prompt "Protected virtualization guest support" 816 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 817 help 818 Select this option, if you want to be able to run this 819 kernel as a protected virtualization KVM guest. 820 Protected virtualization capable machines have a mini hypervisor 821 located at machine level (an ultravisor). With help of the 822 Ultravisor, KVM will be able to run "protected" VMs, special 823 VMs whose memory and management data are unavailable to KVM. 824 825config PFAULT 826 def_bool y 827 prompt "Pseudo page fault support" 828 help 829 Select this option, if you want to use PFAULT pseudo page fault 830 handling under VM. If running native or in LPAR, this option 831 has no effect. If your VM does not support PFAULT, PAGEEX 832 pseudo page fault handling will be used. 833 Note that VM 4.2 supports PFAULT but has a bug in its 834 implementation that causes some problems. 835 Everybody who wants to run Linux under VM != VM4.2 should select 836 this option. 837 838config CMM 839 def_tristate n 840 prompt "Cooperative memory management" 841 help 842 Select this option, if you want to enable the kernel interface 843 to reduce the memory size of the system. This is accomplished 844 by allocating pages of memory and put them "on hold". This only 845 makes sense for a system running under VM where the unused pages 846 will be reused by VM for other guest systems. The interface 847 allows an external monitor to balance memory of many systems. 848 Everybody who wants to run Linux under VM should select this 849 option. 850 851config CMM_IUCV 852 def_bool y 853 prompt "IUCV special message interface to cooperative memory management" 854 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV) 855 help 856 Select this option to enable the special message interface to 857 the cooperative memory management. 858 859config APPLDATA_BASE 860 def_bool n 861 prompt "Linux - VM Monitor Stream, base infrastructure" 862 depends on PROC_SYSCTL 863 help 864 This provides a kernel interface for creating and updating z/VM APPLDATA 865 monitor records. The monitor records are updated at certain time 866 intervals, once the timer is started. 867 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer, 868 i.e. enables or disables monitoring on the Linux side. 869 A custom interval value (in seconds) can be written to 870 /proc/appldata/interval. 871 872 Defaults are 60 seconds interval and timer off. 873 The /proc entries can also be read from, showing the current settings. 874 875config APPLDATA_MEM 876 def_tristate m 877 prompt "Monitor memory management statistics" 878 depends on APPLDATA_BASE && VM_EVENT_COUNTERS 879 help 880 This provides memory management related data to the Linux - VM Monitor 881 Stream, like paging/swapping rate, memory utilisation, etc. 882 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM 883 APPLDATA monitor record, i.e. enables or disables monitoring this record 884 on the z/VM side. 885 886 Default is disabled. 887 The /proc entry can also be read from, showing the current settings. 888 889 This can also be compiled as a module, which will be called 890 appldata_mem.o. 891 892config APPLDATA_OS 893 def_tristate m 894 prompt "Monitor OS statistics" 895 depends on APPLDATA_BASE 896 help 897 This provides OS related data to the Linux - VM Monitor Stream, like 898 CPU utilisation, etc. 899 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM 900 APPLDATA monitor record, i.e. enables or disables monitoring this record 901 on the z/VM side. 902 903 Default is disabled. 904 This can also be compiled as a module, which will be called 905 appldata_os.o. 906 907config APPLDATA_NET_SUM 908 def_tristate m 909 prompt "Monitor overall network statistics" 910 depends on APPLDATA_BASE && NET 911 help 912 This provides network related data to the Linux - VM Monitor Stream, 913 currently there is only a total sum of network I/O statistics, no 914 per-interface data. 915 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM 916 APPLDATA monitor record, i.e. enables or disables monitoring this record 917 on the z/VM side. 918 919 Default is disabled. 920 This can also be compiled as a module, which will be called 921 appldata_net_sum.o. 922 923config S390_HYPFS_FS 924 def_bool y 925 prompt "s390 hypervisor file system support" 926 select SYS_HYPERVISOR 927 help 928 This is a virtual file system intended to provide accounting 929 information in an s390 hypervisor environment. 930 931source "arch/s390/kvm/Kconfig" 932 933config S390_GUEST 934 def_bool y 935 prompt "s390 support for virtio devices" 936 select TTY 937 select VIRTUALIZATION 938 select VIRTIO 939 help 940 Enabling this option adds support for virtio based paravirtual device 941 drivers on s390. 942 943 Select this option if you want to run the kernel as a guest under 944 the KVM hypervisor. 945 946endmenu 947 948config S390_MODULES_SANITY_TEST_HELPERS 949 def_bool n 950 951menu "Selftests" 952 953config S390_UNWIND_SELFTEST 954 def_tristate n 955 depends on KUNIT 956 default KUNIT_ALL_TESTS 957 prompt "Test unwind functions" 958 help 959 This option enables s390 specific stack unwinder testing kernel 960 module. This option is not useful for distributions or general 961 kernels, but only for kernel developers working on architecture code. 962 963 Say N if you are unsure. 964 965config S390_KPROBES_SANITY_TEST 966 def_tristate n 967 prompt "Enable s390 specific kprobes tests" 968 depends on KPROBES 969 depends on KUNIT 970 help 971 This option enables an s390 specific kprobes test module. This option 972 is not useful for distributions or general kernels, but only for kernel 973 developers working on architecture code. 974 975 Say N if you are unsure. 976 977config S390_MODULES_SANITY_TEST 978 def_tristate n 979 depends on KUNIT 980 default KUNIT_ALL_TESTS 981 prompt "Enable s390 specific modules tests" 982 select S390_MODULES_SANITY_TEST_HELPERS 983 help 984 This option enables an s390 specific modules test. This option is 985 not useful for distributions or general kernels, but only for 986 kernel developers working on architecture code. 987 988 Say N if you are unsure. 989endmenu 990