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