1# SPDX-License-Identifier: GPL-2.0 2config MMU 3 def_bool y 4 5config ZONE_DMA 6 def_bool y 7 8config CPU_BIG_ENDIAN 9 def_bool y 10 11config LOCKDEP_SUPPORT 12 def_bool y 13 14config STACKTRACE_SUPPORT 15 def_bool y 16 17config ARCH_HAS_ILOG2_U32 18 def_bool n 19 20config ARCH_HAS_ILOG2_U64 21 def_bool n 22 23config GENERIC_HWEIGHT 24 def_bool y 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 ARCH_SUPPORTS_DEBUG_PAGEALLOC 39 def_bool y 40 41config AUDIT_ARCH 42 def_bool y 43 44config NO_IOPORT_MAP 45 def_bool y 46 47config PCI_QUIRKS 48 def_bool n 49 50config ARCH_SUPPORTS_UPROBES 51 def_bool y 52 53config KASAN_SHADOW_OFFSET 54 hex 55 depends on KASAN 56 default 0x18000000000000 if KASAN_S390_4_LEVEL_PAGING 57 default 0x30000000000 58 59config S390 60 def_bool y 61 select ARCH_BINFMT_ELF_STATE 62 select ARCH_HAS_DEBUG_VM_PGTABLE 63 select ARCH_HAS_DEBUG_WX 64 select ARCH_HAS_DEVMEM_IS_ALLOWED 65 select ARCH_HAS_ELF_RANDOMIZE 66 select ARCH_HAS_FORTIFY_SOURCE 67 select ARCH_HAS_GCOV_PROFILE_ALL 68 select ARCH_HAS_GIGANTIC_PAGE 69 select ARCH_HAS_KCOV 70 select ARCH_HAS_MEM_ENCRYPT 71 select ARCH_HAS_PTE_SPECIAL 72 select ARCH_HAS_SET_MEMORY 73 select ARCH_HAS_STRICT_KERNEL_RWX 74 select ARCH_HAS_STRICT_MODULE_RWX 75 select ARCH_HAS_SYSCALL_WRAPPER 76 select ARCH_HAS_UBSAN_SANITIZE_ALL 77 select ARCH_HAS_VDSO_DATA 78 select ARCH_HAVE_NMI_SAFE_CMPXCHG 79 select ARCH_INLINE_READ_LOCK 80 select ARCH_INLINE_READ_LOCK_BH 81 select ARCH_INLINE_READ_LOCK_IRQ 82 select ARCH_INLINE_READ_LOCK_IRQSAVE 83 select ARCH_INLINE_READ_TRYLOCK 84 select ARCH_INLINE_READ_UNLOCK 85 select ARCH_INLINE_READ_UNLOCK_BH 86 select ARCH_INLINE_READ_UNLOCK_IRQ 87 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE 88 select ARCH_INLINE_SPIN_LOCK 89 select ARCH_INLINE_SPIN_LOCK_BH 90 select ARCH_INLINE_SPIN_LOCK_IRQ 91 select ARCH_INLINE_SPIN_LOCK_IRQSAVE 92 select ARCH_INLINE_SPIN_TRYLOCK 93 select ARCH_INLINE_SPIN_TRYLOCK_BH 94 select ARCH_INLINE_SPIN_UNLOCK 95 select ARCH_INLINE_SPIN_UNLOCK_BH 96 select ARCH_INLINE_SPIN_UNLOCK_IRQ 97 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE 98 select ARCH_INLINE_WRITE_LOCK 99 select ARCH_INLINE_WRITE_LOCK_BH 100 select ARCH_INLINE_WRITE_LOCK_IRQ 101 select ARCH_INLINE_WRITE_LOCK_IRQSAVE 102 select ARCH_INLINE_WRITE_TRYLOCK 103 select ARCH_INLINE_WRITE_UNLOCK 104 select ARCH_INLINE_WRITE_UNLOCK_BH 105 select ARCH_INLINE_WRITE_UNLOCK_IRQ 106 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE 107 select ARCH_STACKWALK 108 select ARCH_SUPPORTS_ATOMIC_RMW 109 select ARCH_SUPPORTS_NUMA_BALANCING 110 select ARCH_USE_BUILTIN_BSWAP 111 select ARCH_USE_CMPXCHG_LOCKREF 112 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 113 select ARCH_WANT_DEFAULT_BPF_JIT 114 select ARCH_WANT_IPC_PARSE_VERSION 115 select BUILDTIME_TABLE_SORT 116 select CLONE_BACKWARDS2 117 select DMA_OPS if PCI 118 select DYNAMIC_FTRACE if FUNCTION_TRACER 119 select GENERIC_CPU_AUTOPROBE 120 select GENERIC_CPU_VULNERABILITIES 121 select GENERIC_FIND_FIRST_BIT 122 select GENERIC_GETTIMEOFDAY 123 select GENERIC_PTDUMP 124 select GENERIC_SMP_IDLE_THREAD 125 select GENERIC_TIME_VSYSCALL 126 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 127 select HAVE_ARCH_AUDITSYSCALL 128 select HAVE_ARCH_JUMP_LABEL 129 select HAVE_ARCH_JUMP_LABEL_RELATIVE 130 select HAVE_ARCH_KASAN 131 select HAVE_ARCH_KASAN_VMALLOC 132 select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES 133 select HAVE_ARCH_SECCOMP_FILTER 134 select HAVE_ARCH_SOFT_DIRTY 135 select HAVE_ARCH_TRACEHOOK 136 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 137 select HAVE_ARCH_VMAP_STACK 138 select HAVE_ASM_MODVERSIONS 139 select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES 140 select HAVE_CMPXCHG_DOUBLE 141 select HAVE_CMPXCHG_LOCAL 142 select HAVE_DEBUG_KMEMLEAK 143 select HAVE_DMA_CONTIGUOUS 144 select HAVE_DYNAMIC_FTRACE 145 select HAVE_DYNAMIC_FTRACE_WITH_REGS 146 select HAVE_FAST_GUP 147 select HAVE_EFFICIENT_UNALIGNED_ACCESS 148 select HAVE_FENTRY 149 select HAVE_FTRACE_MCOUNT_RECORD 150 select HAVE_FUNCTION_ERROR_INJECTION 151 select HAVE_FUNCTION_GRAPH_TRACER 152 select HAVE_FUNCTION_TRACER 153 select HAVE_FUTEX_CMPXCHG if FUTEX 154 select HAVE_GCC_PLUGINS 155 select HAVE_GENERIC_VDSO 156 select HAVE_KERNEL_BZIP2 157 select HAVE_KERNEL_GZIP 158 select HAVE_KERNEL_LZ4 159 select HAVE_KERNEL_LZMA 160 select HAVE_KERNEL_LZO 161 select HAVE_KERNEL_UNCOMPRESSED 162 select HAVE_KERNEL_XZ 163 select HAVE_KPROBES 164 select HAVE_KPROBES_ON_FTRACE 165 select HAVE_KRETPROBES 166 select HAVE_KVM 167 select HAVE_LIVEPATCH 168 select HAVE_PERF_REGS 169 select HAVE_PERF_USER_STACK_DUMP 170 select HAVE_MEMBLOCK_PHYS_MAP 171 select MMU_GATHER_NO_GATHER 172 select HAVE_MOD_ARCH_SPECIFIC 173 select HAVE_NOP_MCOUNT 174 select HAVE_OPROFILE 175 select HAVE_PCI 176 select HAVE_PERF_EVENTS 177 select MMU_GATHER_RCU_TABLE_FREE 178 select HAVE_REGS_AND_STACK_ACCESS_API 179 select HAVE_RELIABLE_STACKTRACE 180 select HAVE_RSEQ 181 select HAVE_SYSCALL_TRACEPOINTS 182 select HAVE_VIRT_CPU_ACCOUNTING 183 select IOMMU_HELPER if PCI 184 select IOMMU_SUPPORT if PCI 185 select MODULES_USE_ELF_RELA 186 select NEED_DMA_MAP_STATE if PCI 187 select NEED_SG_DMA_LENGTH if PCI 188 select OLD_SIGACTION 189 select OLD_SIGSUSPEND3 190 select PCI_DOMAINS if PCI 191 select PCI_MSI if PCI 192 select PCI_MSI_ARCH_FALLBACKS if PCI_MSI 193 select SET_FS 194 select SPARSE_IRQ 195 select SYSCTL_EXCEPTION_TRACE 196 select THREAD_INFO_IN_TASK 197 select TTY 198 select VIRT_CPU_ACCOUNTING 199 select ARCH_HAS_SCALED_CPUTIME 200 select HAVE_NMI 201 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 202 select SWIOTLB 203 select GENERIC_ALLOCATOR 204 imply IMA_SECURE_AND_OR_TRUSTED_BOOT 205 206 207config SCHED_OMIT_FRAME_POINTER 208 def_bool y 209 210config PGTABLE_LEVELS 211 int 212 default 5 213 214source "kernel/livepatch/Kconfig" 215 216menu "Processor type and features" 217 218config HAVE_MARCH_Z900_FEATURES 219 def_bool n 220 221config HAVE_MARCH_Z990_FEATURES 222 def_bool n 223 select HAVE_MARCH_Z900_FEATURES 224 225config HAVE_MARCH_Z9_109_FEATURES 226 def_bool n 227 select HAVE_MARCH_Z990_FEATURES 228 229config HAVE_MARCH_Z10_FEATURES 230 def_bool n 231 select HAVE_MARCH_Z9_109_FEATURES 232 233config HAVE_MARCH_Z196_FEATURES 234 def_bool n 235 select HAVE_MARCH_Z10_FEATURES 236 237config HAVE_MARCH_ZEC12_FEATURES 238 def_bool n 239 select HAVE_MARCH_Z196_FEATURES 240 241config HAVE_MARCH_Z13_FEATURES 242 def_bool n 243 select HAVE_MARCH_ZEC12_FEATURES 244 245config HAVE_MARCH_Z14_FEATURES 246 def_bool n 247 select HAVE_MARCH_Z13_FEATURES 248 249config HAVE_MARCH_Z15_FEATURES 250 def_bool n 251 select HAVE_MARCH_Z14_FEATURES 252 253choice 254 prompt "Processor type" 255 default MARCH_Z196 256 257config MARCH_Z900 258 bool "IBM zSeries model z800 and z900" 259 select HAVE_MARCH_Z900_FEATURES 260 depends on $(cc-option,-march=z900) 261 help 262 Select this to enable optimizations for model z800/z900 (2064 and 263 2066 series). This will enable some optimizations that are not 264 available on older ESA/390 (31 Bit) only CPUs. 265 266config MARCH_Z990 267 bool "IBM zSeries model z890 and z990" 268 select HAVE_MARCH_Z990_FEATURES 269 depends on $(cc-option,-march=z990) 270 help 271 Select this to enable optimizations for model z890/z990 (2084 and 272 2086 series). The kernel will be slightly faster but will not work 273 on older machines. 274 275config MARCH_Z9_109 276 bool "IBM System z9" 277 select HAVE_MARCH_Z9_109_FEATURES 278 depends on $(cc-option,-march=z9-109) 279 help 280 Select this to enable optimizations for IBM System z9 (2094 and 281 2096 series). The kernel will be slightly faster but will not work 282 on older machines. 283 284config MARCH_Z10 285 bool "IBM System z10" 286 select HAVE_MARCH_Z10_FEATURES 287 depends on $(cc-option,-march=z10) 288 help 289 Select this to enable optimizations for IBM System z10 (2097 and 290 2098 series). The kernel will be slightly faster but will not work 291 on older machines. 292 293config MARCH_Z196 294 bool "IBM zEnterprise 114 and 196" 295 select HAVE_MARCH_Z196_FEATURES 296 depends on $(cc-option,-march=z196) 297 help 298 Select this to enable optimizations for IBM zEnterprise 114 and 196 299 (2818 and 2817 series). The kernel will be slightly faster but will 300 not work on older machines. 301 302config MARCH_ZEC12 303 bool "IBM zBC12 and zEC12" 304 select HAVE_MARCH_ZEC12_FEATURES 305 depends on $(cc-option,-march=zEC12) 306 help 307 Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and 308 2827 series). The kernel will be slightly faster but will not work on 309 older machines. 310 311config MARCH_Z13 312 bool "IBM z13s and z13" 313 select HAVE_MARCH_Z13_FEATURES 314 depends on $(cc-option,-march=z13) 315 help 316 Select this to enable optimizations for IBM z13s and z13 (2965 and 317 2964 series). The kernel will be slightly faster but will not work on 318 older machines. 319 320config MARCH_Z14 321 bool "IBM z14 ZR1 and z14" 322 select HAVE_MARCH_Z14_FEATURES 323 depends on $(cc-option,-march=z14) 324 help 325 Select this to enable optimizations for IBM z14 ZR1 and z14 (3907 326 and 3906 series). The kernel will be slightly faster but will not 327 work on older machines. 328 329config MARCH_Z15 330 bool "IBM z15" 331 select HAVE_MARCH_Z15_FEATURES 332 depends on $(cc-option,-march=z15) 333 help 334 Select this to enable optimizations for IBM z15 (8562 335 and 8561 series). The kernel will be slightly faster but will not 336 work on older machines. 337 338endchoice 339 340config MARCH_Z900_TUNE 341 def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT 342 343config MARCH_Z990_TUNE 344 def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT 345 346config MARCH_Z9_109_TUNE 347 def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT 348 349config MARCH_Z10_TUNE 350 def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT 351 352config MARCH_Z196_TUNE 353 def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT 354 355config MARCH_ZEC12_TUNE 356 def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT 357 358config MARCH_Z13_TUNE 359 def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT 360 361config MARCH_Z14_TUNE 362 def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT 363 364config MARCH_Z15_TUNE 365 def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT 366 367choice 368 prompt "Tune code generation" 369 default TUNE_DEFAULT 370 help 371 Cause the compiler to tune (-mtune) the generated code for a machine. 372 This will make the code run faster on the selected machine but 373 somewhat slower on other machines. 374 This option only changes how the compiler emits instructions, not the 375 selection of instructions itself, so the resulting kernel will run on 376 all other machines. 377 378config TUNE_DEFAULT 379 bool "Default" 380 help 381 Tune the generated code for the target processor for which the kernel 382 will be compiled. 383 384config TUNE_Z900 385 bool "IBM zSeries model z800 and z900" 386 depends on $(cc-option,-mtune=z900) 387 388config TUNE_Z990 389 bool "IBM zSeries model z890 and z990" 390 depends on $(cc-option,-mtune=z990) 391 392config TUNE_Z9_109 393 bool "IBM System z9" 394 depends on $(cc-option,-mtune=z9-109) 395 396config TUNE_Z10 397 bool "IBM System z10" 398 depends on $(cc-option,-mtune=z10) 399 400config TUNE_Z196 401 bool "IBM zEnterprise 114 and 196" 402 depends on $(cc-option,-mtune=z196) 403 404config TUNE_ZEC12 405 bool "IBM zBC12 and zEC12" 406 depends on $(cc-option,-mtune=zEC12) 407 408config TUNE_Z13 409 bool "IBM z13s and z13" 410 depends on $(cc-option,-mtune=z13) 411 412config TUNE_Z14 413 bool "IBM z14 ZR1 and z14" 414 depends on $(cc-option,-mtune=z14) 415 416config TUNE_Z15 417 bool "IBM z15" 418 depends on $(cc-option,-mtune=z15) 419 420endchoice 421 422config 64BIT 423 def_bool y 424 425config COMPAT 426 def_bool y 427 prompt "Kernel support for 31 bit emulation" 428 select COMPAT_BINFMT_ELF if BINFMT_ELF 429 select ARCH_WANT_OLD_COMPAT_IPC 430 select COMPAT_OLD_SIGACTION 431 select HAVE_UID16 432 depends on MULTIUSER 433 help 434 Select this option if you want to enable your system kernel to 435 handle system-calls from ELF binaries for 31 bit ESA. This option 436 (and some other stuff like libraries and such) is needed for 437 executing 31 bit applications. It is safe to say "Y". 438 439config SYSVIPC_COMPAT 440 def_bool y if COMPAT && SYSVIPC 441 442config SMP 443 def_bool y 444 445config NR_CPUS 446 int "Maximum number of CPUs (2-512)" 447 range 2 512 448 default "64" 449 help 450 This allows you to specify the maximum number of CPUs which this 451 kernel will support. The maximum supported value is 512 and the 452 minimum value which makes sense is 2. 453 454 This is purely to save memory - each supported CPU adds 455 approximately sixteen kilobytes to the kernel image. 456 457config HOTPLUG_CPU 458 def_bool y 459 460config NUMA 461 bool "NUMA support" 462 depends on SCHED_TOPOLOGY 463 default n 464 help 465 Enable NUMA support 466 467 This option adds NUMA support to the kernel. 468 469config NODES_SHIFT 470 int 471 depends on NEED_MULTIPLE_NODES 472 default "1" 473 474config SCHED_SMT 475 def_bool n 476 477config SCHED_MC 478 def_bool n 479 480config SCHED_BOOK 481 def_bool n 482 483config SCHED_DRAWER 484 def_bool n 485 486config SCHED_TOPOLOGY 487 def_bool y 488 prompt "Topology scheduler support" 489 select SCHED_SMT 490 select SCHED_MC 491 select SCHED_BOOK 492 select SCHED_DRAWER 493 help 494 Topology scheduler support improves the CPU scheduler's decision 495 making when dealing with machines that have multi-threading, 496 multiple cores or multiple books. 497 498source "kernel/Kconfig.hz" 499 500config KEXEC 501 def_bool y 502 select KEXEC_CORE 503 504config KEXEC_FILE 505 bool "kexec file based system call" 506 select KEXEC_CORE 507 select BUILD_BIN2C 508 depends on CRYPTO 509 depends on CRYPTO_SHA256 510 depends on CRYPTO_SHA256_S390 511 help 512 Enable the kexec file based system call. In contrast to the normal 513 kexec system call this system call takes file descriptors for the 514 kernel and initramfs as arguments. 515 516config ARCH_HAS_KEXEC_PURGATORY 517 def_bool y 518 depends on KEXEC_FILE 519 520config KEXEC_SIG 521 bool "Verify kernel signature during kexec_file_load() syscall" 522 depends on KEXEC_FILE && MODULE_SIG_FORMAT 523 help 524 This option makes kernel signature verification mandatory for 525 the kexec_file_load() syscall. 526 527 In addition to that option, you need to enable signature 528 verification for the corresponding kernel image type being 529 loaded in order for this to work. 530 531config ARCH_RANDOM 532 def_bool y 533 prompt "s390 architectural random number generation API" 534 help 535 Enable the s390 architectural random number generation API 536 to provide random data for all consumers within the Linux 537 kernel. 538 539 When enabled the arch_random_* functions declared in linux/random.h 540 are implemented. The implementation is based on the s390 CPACF 541 instruction subfunction TRNG which provides a real true random 542 number generator. 543 544 If unsure, say Y. 545 546config KERNEL_NOBP 547 def_bool n 548 prompt "Enable modified branch prediction for the kernel by default" 549 help 550 If this option is selected the kernel will switch to a modified 551 branch prediction mode if the firmware interface is available. 552 The modified branch prediction mode improves the behaviour in 553 regard to speculative execution. 554 555 With the option enabled the kernel parameter "nobp=0" or "nospec" 556 can be used to run the kernel in the normal branch prediction mode. 557 558 With the option disabled the modified branch prediction mode is 559 enabled with the "nobp=1" kernel parameter. 560 561 If unsure, say N. 562 563config EXPOLINE 564 def_bool n 565 prompt "Avoid speculative indirect branches in the kernel" 566 help 567 Compile the kernel with the expoline compiler options to guard 568 against kernel-to-user data leaks by avoiding speculative indirect 569 branches. 570 Requires a compiler with -mindirect-branch=thunk support for full 571 protection. The kernel may run slower. 572 573 If unsure, say N. 574 575choice 576 prompt "Expoline default" 577 depends on EXPOLINE 578 default EXPOLINE_FULL 579 580config EXPOLINE_OFF 581 bool "spectre_v2=off" 582 583config EXPOLINE_AUTO 584 bool "spectre_v2=auto" 585 586config EXPOLINE_FULL 587 bool "spectre_v2=on" 588 589endchoice 590 591config RELOCATABLE 592 bool "Build a relocatable kernel" 593 select MODULE_REL_CRCS if MODVERSIONS 594 default y 595 help 596 This builds a kernel image that retains relocation information 597 so it can be loaded at an arbitrary address. 598 The kernel is linked as a position-independent executable (PIE) 599 and contains dynamic relocations which are processed early in the 600 bootup process. 601 The relocations make the kernel image about 15% larger (compressed 602 10%), but are discarded at runtime. 603 604config RANDOMIZE_BASE 605 bool "Randomize the address of the kernel image (KASLR)" 606 depends on RELOCATABLE 607 default y 608 help 609 In support of Kernel Address Space Layout Randomization (KASLR), 610 this randomizes the address at which the kernel image is loaded, 611 as a security feature that deters exploit attempts relying on 612 knowledge of the location of kernel internals. 613 614endmenu 615 616menu "Memory setup" 617 618config ARCH_SPARSEMEM_ENABLE 619 def_bool y 620 select SPARSEMEM_VMEMMAP_ENABLE 621 select SPARSEMEM_VMEMMAP 622 623config ARCH_SPARSEMEM_DEFAULT 624 def_bool y 625 626config ARCH_ENABLE_MEMORY_HOTPLUG 627 def_bool y if SPARSEMEM 628 629config ARCH_ENABLE_MEMORY_HOTREMOVE 630 def_bool y 631 632config ARCH_ENABLE_SPLIT_PMD_PTLOCK 633 def_bool y 634 635config MAX_PHYSMEM_BITS 636 int "Maximum size of supported physical memory in bits (42-53)" 637 range 42 53 638 default "46" 639 help 640 This option specifies the maximum supported size of physical memory 641 in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB). 642 Increasing the number of bits also increases the kernel image size. 643 By default 46 bits (64TB) are supported. 644 645config PACK_STACK 646 def_bool y 647 prompt "Pack kernel stack" 648 help 649 This option enables the compiler option -mkernel-backchain if it 650 is available. If the option is available the compiler supports 651 the new stack layout which dramatically reduces the minimum stack 652 frame size. With an old compiler a non-leaf function needs a 653 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With 654 -mkernel-backchain the minimum size drops to 16 byte on 31 bit 655 and 24 byte on 64 bit. 656 657 Say Y if you are unsure. 658 659config CHECK_STACK 660 def_bool y 661 depends on !VMAP_STACK 662 prompt "Detect kernel stack overflow" 663 help 664 This option enables the compiler option -mstack-guard and 665 -mstack-size if they are available. If the compiler supports them 666 it will emit additional code to each function prolog to trigger 667 an illegal operation if the kernel stack is about to overflow. 668 669 Say N if you are unsure. 670 671config STACK_GUARD 672 int "Size of the guard area (128-1024)" 673 range 128 1024 674 depends on CHECK_STACK 675 default "256" 676 help 677 This allows you to specify the size of the guard area at the lower 678 end of the kernel stack. If the kernel stack points into the guard 679 area on function entry an illegal operation is triggered. The size 680 needs to be a power of 2. Please keep in mind that the size of an 681 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit. 682 The minimum size for the stack guard should be 256 for 31 bit and 683 512 for 64 bit. 684 685config WARN_DYNAMIC_STACK 686 def_bool n 687 prompt "Emit compiler warnings for function with dynamic stack usage" 688 help 689 This option enables the compiler option -mwarn-dynamicstack. If the 690 compiler supports this options generates warnings for functions 691 that dynamically allocate stack space using alloca. 692 693 Say N if you are unsure. 694 695endmenu 696 697menu "I/O subsystem" 698 699config QDIO 700 def_tristate y 701 prompt "QDIO support" 702 help 703 This driver provides the Queued Direct I/O base support for 704 IBM System z. 705 706 To compile this driver as a module, choose M here: the 707 module will be called qdio. 708 709 If unsure, say Y. 710 711if PCI 712 713config PCI_NR_FUNCTIONS 714 int "Maximum number of PCI functions (1-4096)" 715 range 1 4096 716 default "128" 717 help 718 This allows you to specify the maximum number of PCI functions which 719 this kernel will support. 720 721endif # PCI 722 723config HAS_IOMEM 724 def_bool PCI 725 726config CHSC_SCH 727 def_tristate m 728 prompt "Support for CHSC subchannels" 729 help 730 This driver allows usage of CHSC subchannels. A CHSC subchannel 731 is usually present on LPAR only. 732 The driver creates a device /dev/chsc, which may be used to 733 obtain I/O configuration information about the machine and 734 to issue asynchronous chsc commands (DANGEROUS). 735 You will usually only want to use this interface on a special 736 LPAR designated for system management. 737 738 To compile this driver as a module, choose M here: the 739 module will be called chsc_sch. 740 741 If unsure, say N. 742 743config SCM_BUS 744 def_bool y 745 prompt "SCM bus driver" 746 help 747 Bus driver for Storage Class Memory. 748 749config EADM_SCH 750 def_tristate m 751 prompt "Support for EADM subchannels" 752 depends on SCM_BUS 753 help 754 This driver allows usage of EADM subchannels. EADM subchannels act 755 as a communication vehicle for SCM increments. 756 757 To compile this driver as a module, choose M here: the 758 module will be called eadm_sch. 759 760config VFIO_CCW 761 def_tristate n 762 prompt "Support for VFIO-CCW subchannels" 763 depends on S390_CCW_IOMMU && VFIO_MDEV 764 help 765 This driver allows usage of I/O subchannels via VFIO-CCW. 766 767 To compile this driver as a module, choose M here: the 768 module will be called vfio_ccw. 769 770config VFIO_AP 771 def_tristate n 772 prompt "VFIO support for AP devices" 773 depends on S390_AP_IOMMU && VFIO_MDEV_DEVICE && KVM 774 depends on ZCRYPT 775 help 776 This driver grants access to Adjunct Processor (AP) devices 777 via the VFIO mediated device interface. 778 779 To compile this driver as a module, choose M here: the module 780 will be called vfio_ap. 781 782endmenu 783 784menu "Dump support" 785 786config CRASH_DUMP 787 bool "kernel crash dumps" 788 select KEXEC 789 help 790 Generate crash dump after being started by kexec. 791 Crash dump kernels are loaded in the main kernel with kexec-tools 792 into a specially reserved region and then later executed after 793 a crash by kdump/kexec. 794 Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this. 795 This option also enables s390 zfcpdump. 796 See also <file:Documentation/s390/zfcpdump.rst> 797 798endmenu 799 800config CCW 801 def_bool y 802 803config HAVE_PNETID 804 tristate 805 default (SMC || CCWGROUP) 806 807menu "Virtualization" 808 809config PROTECTED_VIRTUALIZATION_GUEST 810 def_bool n 811 prompt "Protected virtualization guest support" 812 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 813 help 814 Select this option, if you want to be able to run this 815 kernel as a protected virtualization KVM guest. 816 Protected virtualization capable machines have a mini hypervisor 817 located at machine level (an ultravisor). With help of the 818 Ultravisor, KVM will be able to run "protected" VMs, special 819 VMs whose memory and management data are unavailable to KVM. 820 821config PFAULT 822 def_bool y 823 prompt "Pseudo page fault support" 824 help 825 Select this option, if you want to use PFAULT pseudo page fault 826 handling under VM. If running native or in LPAR, this option 827 has no effect. If your VM does not support PFAULT, PAGEEX 828 pseudo page fault handling will be used. 829 Note that VM 4.2 supports PFAULT but has a bug in its 830 implementation that causes some problems. 831 Everybody who wants to run Linux under VM != VM4.2 should select 832 this option. 833 834config CMM 835 def_tristate n 836 prompt "Cooperative memory management" 837 help 838 Select this option, if you want to enable the kernel interface 839 to reduce the memory size of the system. This is accomplished 840 by allocating pages of memory and put them "on hold". This only 841 makes sense for a system running under VM where the unused pages 842 will be reused by VM for other guest systems. The interface 843 allows an external monitor to balance memory of many systems. 844 Everybody who wants to run Linux under VM should select this 845 option. 846 847config CMM_IUCV 848 def_bool y 849 prompt "IUCV special message interface to cooperative memory management" 850 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV) 851 help 852 Select this option to enable the special message interface to 853 the cooperative memory management. 854 855config APPLDATA_BASE 856 def_bool n 857 prompt "Linux - VM Monitor Stream, base infrastructure" 858 depends on PROC_FS 859 help 860 This provides a kernel interface for creating and updating z/VM APPLDATA 861 monitor records. The monitor records are updated at certain time 862 intervals, once the timer is started. 863 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer, 864 i.e. enables or disables monitoring on the Linux side. 865 A custom interval value (in seconds) can be written to 866 /proc/appldata/interval. 867 868 Defaults are 60 seconds interval and timer off. 869 The /proc entries can also be read from, showing the current settings. 870 871config APPLDATA_MEM 872 def_tristate m 873 prompt "Monitor memory management statistics" 874 depends on APPLDATA_BASE && VM_EVENT_COUNTERS 875 help 876 This provides memory management related data to the Linux - VM Monitor 877 Stream, like paging/swapping rate, memory utilisation, etc. 878 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM 879 APPLDATA monitor record, i.e. enables or disables monitoring this record 880 on the z/VM side. 881 882 Default is disabled. 883 The /proc entry can also be read from, showing the current settings. 884 885 This can also be compiled as a module, which will be called 886 appldata_mem.o. 887 888config APPLDATA_OS 889 def_tristate m 890 prompt "Monitor OS statistics" 891 depends on APPLDATA_BASE 892 help 893 This provides OS related data to the Linux - VM Monitor Stream, like 894 CPU utilisation, etc. 895 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM 896 APPLDATA monitor record, i.e. enables or disables monitoring this record 897 on the z/VM side. 898 899 Default is disabled. 900 This can also be compiled as a module, which will be called 901 appldata_os.o. 902 903config APPLDATA_NET_SUM 904 def_tristate m 905 prompt "Monitor overall network statistics" 906 depends on APPLDATA_BASE && NET 907 help 908 This provides network related data to the Linux - VM Monitor Stream, 909 currently there is only a total sum of network I/O statistics, no 910 per-interface data. 911 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM 912 APPLDATA monitor record, i.e. enables or disables monitoring this record 913 on the z/VM side. 914 915 Default is disabled. 916 This can also be compiled as a module, which will be called 917 appldata_net_sum.o. 918 919config S390_HYPFS_FS 920 def_bool y 921 prompt "s390 hypervisor file system support" 922 select SYS_HYPERVISOR 923 help 924 This is a virtual file system intended to provide accounting 925 information in an s390 hypervisor environment. 926 927source "arch/s390/kvm/Kconfig" 928 929config S390_GUEST 930 def_bool y 931 prompt "s390 support for virtio devices" 932 select TTY 933 select VIRTUALIZATION 934 select VIRTIO 935 help 936 Enabling this option adds support for virtio based paravirtual device 937 drivers on s390. 938 939 Select this option if you want to run the kernel as a guest under 940 the KVM hypervisor. 941 942endmenu 943 944menu "Selftests" 945 946config S390_UNWIND_SELFTEST 947 def_tristate n 948 prompt "Test unwind functions" 949 help 950 This option enables s390 specific stack unwinder testing kernel 951 module. This option is not useful for distributions or general 952 kernels, but only for kernel developers working on architecture code. 953 954 Say N if you are unsure. 955 956endmenu 957