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 SMP && PREEMPT 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_DEVMEM_IS_ALLOWED 63 select ARCH_HAS_ELF_RANDOMIZE 64 select ARCH_HAS_FORTIFY_SOURCE 65 select ARCH_HAS_GCOV_PROFILE_ALL 66 select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA 67 select ARCH_HAS_KCOV 68 select ARCH_HAS_PTE_SPECIAL 69 select ARCH_HAS_SET_MEMORY 70 select ARCH_HAS_STRICT_KERNEL_RWX 71 select ARCH_HAS_STRICT_MODULE_RWX 72 select ARCH_HAS_SYSCALL_WRAPPER 73 select ARCH_HAS_UBSAN_SANITIZE_ALL 74 select ARCH_HAVE_NMI_SAFE_CMPXCHG 75 select ARCH_INLINE_READ_LOCK 76 select ARCH_INLINE_READ_LOCK_BH 77 select ARCH_INLINE_READ_LOCK_IRQ 78 select ARCH_INLINE_READ_LOCK_IRQSAVE 79 select ARCH_INLINE_READ_TRYLOCK 80 select ARCH_INLINE_READ_UNLOCK 81 select ARCH_INLINE_READ_UNLOCK_BH 82 select ARCH_INLINE_READ_UNLOCK_IRQ 83 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE 84 select ARCH_INLINE_SPIN_LOCK 85 select ARCH_INLINE_SPIN_LOCK_BH 86 select ARCH_INLINE_SPIN_LOCK_IRQ 87 select ARCH_INLINE_SPIN_LOCK_IRQSAVE 88 select ARCH_INLINE_SPIN_TRYLOCK 89 select ARCH_INLINE_SPIN_TRYLOCK_BH 90 select ARCH_INLINE_SPIN_UNLOCK 91 select ARCH_INLINE_SPIN_UNLOCK_BH 92 select ARCH_INLINE_SPIN_UNLOCK_IRQ 93 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE 94 select ARCH_INLINE_WRITE_LOCK 95 select ARCH_INLINE_WRITE_LOCK_BH 96 select ARCH_INLINE_WRITE_LOCK_IRQ 97 select ARCH_INLINE_WRITE_LOCK_IRQSAVE 98 select ARCH_INLINE_WRITE_TRYLOCK 99 select ARCH_INLINE_WRITE_UNLOCK 100 select ARCH_INLINE_WRITE_UNLOCK_BH 101 select ARCH_INLINE_WRITE_UNLOCK_IRQ 102 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE 103 select ARCH_SAVE_PAGE_KEYS if HIBERNATION 104 select ARCH_SUPPORTS_ATOMIC_RMW 105 select ARCH_SUPPORTS_NUMA_BALANCING 106 select ARCH_USE_BUILTIN_BSWAP 107 select ARCH_USE_CMPXCHG_LOCKREF 108 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 109 select ARCH_WANT_IPC_PARSE_VERSION 110 select BUILDTIME_EXTABLE_SORT 111 select CLONE_BACKWARDS2 112 select DYNAMIC_FTRACE if FUNCTION_TRACER 113 select GENERIC_CLOCKEVENTS 114 select GENERIC_CPU_AUTOPROBE 115 select GENERIC_CPU_DEVICES if !SMP 116 select GENERIC_CPU_VULNERABILITIES 117 select GENERIC_FIND_FIRST_BIT 118 select GENERIC_SMP_IDLE_THREAD 119 select GENERIC_TIME_VSYSCALL 120 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 121 select HAVE_ARCH_AUDITSYSCALL 122 select HAVE_ARCH_JUMP_LABEL 123 select HAVE_ARCH_JUMP_LABEL_RELATIVE 124 select HAVE_ARCH_KASAN 125 select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES 126 select HAVE_ARCH_SECCOMP_FILTER 127 select HAVE_ARCH_SOFT_DIRTY 128 select HAVE_ARCH_TRACEHOOK 129 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 130 select HAVE_ARCH_VMAP_STACK 131 select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES 132 select HAVE_CMPXCHG_DOUBLE 133 select HAVE_CMPXCHG_LOCAL 134 select HAVE_COPY_THREAD_TLS 135 select HAVE_DEBUG_KMEMLEAK 136 select HAVE_DMA_CONTIGUOUS 137 select HAVE_DYNAMIC_FTRACE 138 select HAVE_DYNAMIC_FTRACE_WITH_REGS 139 select HAVE_EFFICIENT_UNALIGNED_ACCESS 140 select HAVE_FENTRY 141 select HAVE_FTRACE_MCOUNT_RECORD 142 select HAVE_FUNCTION_GRAPH_TRACER 143 select HAVE_FUNCTION_TRACER 144 select HAVE_FUTEX_CMPXCHG if FUTEX 145 select HAVE_GCC_PLUGINS 146 select HAVE_GENERIC_GUP 147 select HAVE_KERNEL_BZIP2 148 select HAVE_KERNEL_GZIP 149 select HAVE_KERNEL_LZ4 150 select HAVE_KERNEL_LZMA 151 select HAVE_KERNEL_LZO 152 select HAVE_KERNEL_UNCOMPRESSED 153 select HAVE_KERNEL_XZ 154 select HAVE_KPROBES 155 select HAVE_KRETPROBES 156 select HAVE_KVM 157 select HAVE_LIVEPATCH 158 select HAVE_PERF_REGS 159 select HAVE_PERF_USER_STACK_DUMP 160 select HAVE_MEMBLOCK_NODE_MAP 161 select HAVE_MEMBLOCK_PHYS_MAP 162 select HAVE_MMU_GATHER_NO_GATHER 163 select HAVE_MOD_ARCH_SPECIFIC 164 select HAVE_NOP_MCOUNT 165 select HAVE_OPROFILE 166 select HAVE_PCI 167 select HAVE_PERF_EVENTS 168 select HAVE_RCU_TABLE_FREE 169 select HAVE_REGS_AND_STACK_ACCESS_API 170 select HAVE_RSEQ 171 select HAVE_SYSCALL_TRACEPOINTS 172 select HAVE_VIRT_CPU_ACCOUNTING 173 select IOMMU_HELPER if PCI 174 select IOMMU_SUPPORT if PCI 175 select MODULES_USE_ELF_RELA 176 select NEED_DMA_MAP_STATE if PCI 177 select NEED_SG_DMA_LENGTH if PCI 178 select OLD_SIGACTION 179 select OLD_SIGSUSPEND3 180 select PCI_DOMAINS if PCI 181 select PCI_MSI if PCI 182 select SPARSE_IRQ 183 select SYSCTL_EXCEPTION_TRACE 184 select THREAD_INFO_IN_TASK 185 select TTY 186 select VIRT_CPU_ACCOUNTING 187 select ARCH_HAS_SCALED_CPUTIME 188 select HAVE_NMI 189 190 191config SCHED_OMIT_FRAME_POINTER 192 def_bool y 193 194config PGTABLE_LEVELS 195 int 196 default 5 197 198source "kernel/livepatch/Kconfig" 199 200menu "Processor type and features" 201 202config HAVE_MARCH_Z900_FEATURES 203 def_bool n 204 205config HAVE_MARCH_Z990_FEATURES 206 def_bool n 207 select HAVE_MARCH_Z900_FEATURES 208 209config HAVE_MARCH_Z9_109_FEATURES 210 def_bool n 211 select HAVE_MARCH_Z990_FEATURES 212 213config HAVE_MARCH_Z10_FEATURES 214 def_bool n 215 select HAVE_MARCH_Z9_109_FEATURES 216 217config HAVE_MARCH_Z196_FEATURES 218 def_bool n 219 select HAVE_MARCH_Z10_FEATURES 220 221config HAVE_MARCH_ZEC12_FEATURES 222 def_bool n 223 select HAVE_MARCH_Z196_FEATURES 224 225config HAVE_MARCH_Z13_FEATURES 226 def_bool n 227 select HAVE_MARCH_ZEC12_FEATURES 228 229config HAVE_MARCH_Z14_FEATURES 230 def_bool n 231 select HAVE_MARCH_Z13_FEATURES 232 233choice 234 prompt "Processor type" 235 default MARCH_Z196 236 237config MARCH_Z900 238 bool "IBM zSeries model z800 and z900" 239 depends on !CC_IS_CLANG 240 select HAVE_MARCH_Z900_FEATURES 241 help 242 Select this to enable optimizations for model z800/z900 (2064 and 243 2066 series). This will enable some optimizations that are not 244 available on older ESA/390 (31 Bit) only CPUs. 245 246config MARCH_Z990 247 bool "IBM zSeries model z890 and z990" 248 depends on !CC_IS_CLANG 249 select HAVE_MARCH_Z990_FEATURES 250 help 251 Select this to enable optimizations for model z890/z990 (2084 and 252 2086 series). The kernel will be slightly faster but will not work 253 on older machines. 254 255config MARCH_Z9_109 256 bool "IBM System z9" 257 depends on !CC_IS_CLANG 258 select HAVE_MARCH_Z9_109_FEATURES 259 help 260 Select this to enable optimizations for IBM System z9 (2094 and 261 2096 series). The kernel will be slightly faster but will not work 262 on older machines. 263 264config MARCH_Z10 265 bool "IBM System z10" 266 select HAVE_MARCH_Z10_FEATURES 267 help 268 Select this to enable optimizations for IBM System z10 (2097 and 269 2098 series). The kernel will be slightly faster but will not work 270 on older machines. 271 272config MARCH_Z196 273 bool "IBM zEnterprise 114 and 196" 274 select HAVE_MARCH_Z196_FEATURES 275 help 276 Select this to enable optimizations for IBM zEnterprise 114 and 196 277 (2818 and 2817 series). The kernel will be slightly faster but will 278 not work on older machines. 279 280config MARCH_ZEC12 281 bool "IBM zBC12 and zEC12" 282 select HAVE_MARCH_ZEC12_FEATURES 283 help 284 Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and 285 2827 series). The kernel will be slightly faster but will not work on 286 older machines. 287 288config MARCH_Z13 289 bool "IBM z13s and z13" 290 select HAVE_MARCH_Z13_FEATURES 291 help 292 Select this to enable optimizations for IBM z13s and z13 (2965 and 293 2964 series). The kernel will be slightly faster but will not work on 294 older machines. 295 296config MARCH_Z14 297 bool "IBM z14 ZR1 and z14" 298 select HAVE_MARCH_Z14_FEATURES 299 help 300 Select this to enable optimizations for IBM z14 ZR1 and z14 (3907 301 and 3906 series). The kernel will be slightly faster but will not 302 work on older machines. 303 304endchoice 305 306config MARCH_Z900_TUNE 307 def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT 308 309config MARCH_Z990_TUNE 310 def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT 311 312config MARCH_Z9_109_TUNE 313 def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT 314 315config MARCH_Z10_TUNE 316 def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT 317 318config MARCH_Z196_TUNE 319 def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT 320 321config MARCH_ZEC12_TUNE 322 def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT 323 324config MARCH_Z13_TUNE 325 def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT 326 327config MARCH_Z14_TUNE 328 def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT 329 330choice 331 prompt "Tune code generation" 332 default TUNE_DEFAULT 333 help 334 Cause the compiler to tune (-mtune) the generated code for a machine. 335 This will make the code run faster on the selected machine but 336 somewhat slower on other machines. 337 This option only changes how the compiler emits instructions, not the 338 selection of instructions itself, so the resulting kernel will run on 339 all other machines. 340 341config TUNE_DEFAULT 342 bool "Default" 343 help 344 Tune the generated code for the target processor for which the kernel 345 will be compiled. 346 347config TUNE_Z900 348 bool "IBM zSeries model z800 and z900" 349 depends on !CC_IS_CLANG 350 351config TUNE_Z990 352 bool "IBM zSeries model z890 and z990" 353 depends on !CC_IS_CLANG 354 355config TUNE_Z9_109 356 bool "IBM System z9" 357 depends on !CC_IS_CLANG 358 359config TUNE_Z10 360 bool "IBM System z10" 361 362config TUNE_Z196 363 bool "IBM zEnterprise 114 and 196" 364 365config TUNE_ZEC12 366 bool "IBM zBC12 and zEC12" 367 368config TUNE_Z13 369 bool "IBM z13" 370 371config TUNE_Z14 372 bool "IBM z14" 373 374endchoice 375 376config 64BIT 377 def_bool y 378 379config COMPAT 380 def_bool y 381 prompt "Kernel support for 31 bit emulation" 382 select COMPAT_BINFMT_ELF if BINFMT_ELF 383 select ARCH_WANT_OLD_COMPAT_IPC 384 select COMPAT_OLD_SIGACTION 385 select HAVE_UID16 386 depends on MULTIUSER 387 help 388 Select this option if you want to enable your system kernel to 389 handle system-calls from ELF binaries for 31 bit ESA. This option 390 (and some other stuff like libraries and such) is needed for 391 executing 31 bit applications. It is safe to say "Y". 392 393config COMPAT_VDSO 394 def_bool COMPAT && !CC_IS_CLANG 395 396config SYSVIPC_COMPAT 397 def_bool y if COMPAT && SYSVIPC 398 399config SMP 400 def_bool y 401 prompt "Symmetric multi-processing support" 402 ---help--- 403 This enables support for systems with more than one CPU. If you have 404 a system with only one CPU, like most personal computers, say N. If 405 you have a system with more than one CPU, say Y. 406 407 If you say N here, the kernel will run on uni- and multiprocessor 408 machines, but will use only one CPU of a multiprocessor machine. If 409 you say Y here, the kernel will run on many, but not all, 410 uniprocessor machines. On a uniprocessor machine, the kernel 411 will run faster if you say N here. 412 413 See also the SMP-HOWTO available at 414 <http://www.tldp.org/docs.html#howto>. 415 416 Even if you don't know what to do here, say Y. 417 418config NR_CPUS 419 int "Maximum number of CPUs (2-512)" 420 range 2 512 421 depends on SMP 422 default "64" 423 help 424 This allows you to specify the maximum number of CPUs which this 425 kernel will support. The maximum supported value is 512 and the 426 minimum value which makes sense is 2. 427 428 This is purely to save memory - each supported CPU adds 429 approximately sixteen kilobytes to the kernel image. 430 431config HOTPLUG_CPU 432 def_bool y 433 prompt "Support for hot-pluggable CPUs" 434 depends on SMP 435 help 436 Say Y here to be able to turn CPUs off and on. CPUs 437 can be controlled through /sys/devices/system/cpu/cpu#. 438 Say N if you want to disable CPU hotplug. 439 440# Some NUMA nodes have memory ranges that span 441# other nodes. Even though a pfn is valid and 442# between a node's start and end pfns, it may not 443# reside on that node. See memmap_init_zone() 444# for details. <- They meant memory holes! 445config NODES_SPAN_OTHER_NODES 446 def_bool NUMA 447 448config NUMA 449 bool "NUMA support" 450 depends on SMP && SCHED_TOPOLOGY 451 default n 452 help 453 Enable NUMA support 454 455 This option adds NUMA support to the kernel. 456 457 An operation mode can be selected by appending 458 numa=<method> to the kernel command line. 459 460 The default behaviour is identical to appending numa=plain to 461 the command line. This will create just one node with all 462 available memory and all CPUs in it. 463 464config NODES_SHIFT 465 int "Maximum NUMA nodes (as a power of 2)" 466 range 1 10 467 depends on NUMA 468 default "4" 469 help 470 Specify the maximum number of NUMA nodes available on the target 471 system. Increases memory reserved to accommodate various tables. 472 473menu "Select NUMA modes" 474 depends on NUMA 475 476config NUMA_EMU 477 bool "NUMA emulation" 478 default y 479 help 480 Numa emulation mode will split the available system memory into 481 equal chunks which then are distributed over the configured number 482 of nodes in a round-robin manner. 483 484 The number of fake nodes is limited by the number of available memory 485 chunks (i.e. memory size / fake size) and the number of supported 486 nodes in the kernel. 487 488 The CPUs are assigned to the nodes in a way that partially respects 489 the original machine topology (if supported by the machine). 490 Fair distribution of the CPUs is not guaranteed. 491 492config EMU_SIZE 493 hex "NUMA emulation memory chunk size" 494 default 0x10000000 495 range 0x400000 0x100000000 496 depends on NUMA_EMU 497 help 498 Select the default size by which the memory is chopped and then 499 assigned to emulated NUMA nodes. 500 501 This can be overridden by specifying 502 503 emu_size=<n> 504 505 on the kernel command line where also suffixes K, M, G, and T are 506 supported. 507 508endmenu 509 510config SCHED_SMT 511 def_bool n 512 513config SCHED_MC 514 def_bool n 515 516config SCHED_BOOK 517 def_bool n 518 519config SCHED_DRAWER 520 def_bool n 521 522config SCHED_TOPOLOGY 523 def_bool y 524 prompt "Topology scheduler support" 525 depends on SMP 526 select SCHED_SMT 527 select SCHED_MC 528 select SCHED_BOOK 529 select SCHED_DRAWER 530 help 531 Topology scheduler support improves the CPU scheduler's decision 532 making when dealing with machines that have multi-threading, 533 multiple cores or multiple books. 534 535source "kernel/Kconfig.hz" 536 537config KEXEC 538 def_bool y 539 select KEXEC_CORE 540 541config KEXEC_FILE 542 bool "kexec file based system call" 543 select KEXEC_CORE 544 select BUILD_BIN2C 545 depends on CRYPTO 546 depends on CRYPTO_SHA256 547 depends on CRYPTO_SHA256_S390 548 help 549 Enable the kexec file based system call. In contrast to the normal 550 kexec system call this system call takes file descriptors for the 551 kernel and initramfs as arguments. 552 553config ARCH_HAS_KEXEC_PURGATORY 554 def_bool y 555 depends on KEXEC_FILE 556 557config KEXEC_VERIFY_SIG 558 bool "Verify kernel signature during kexec_file_load() syscall" 559 depends on KEXEC_FILE && SYSTEM_DATA_VERIFICATION 560 help 561 This option makes kernel signature verification mandatory for 562 the kexec_file_load() syscall. 563 564 In addition to that option, you need to enable signature 565 verification for the corresponding kernel image type being 566 loaded in order for this to work. 567 568config ARCH_RANDOM 569 def_bool y 570 prompt "s390 architectural random number generation API" 571 help 572 Enable the s390 architectural random number generation API 573 to provide random data for all consumers within the Linux 574 kernel. 575 576 When enabled the arch_random_* functions declared in linux/random.h 577 are implemented. The implementation is based on the s390 CPACF 578 instruction subfunction TRNG which provides a real true random 579 number generator. 580 581 If unsure, say Y. 582 583config KERNEL_NOBP 584 def_bool n 585 prompt "Enable modified branch prediction for the kernel by default" 586 help 587 If this option is selected the kernel will switch to a modified 588 branch prediction mode if the firmware interface is available. 589 The modified branch prediction mode improves the behaviour in 590 regard to speculative execution. 591 592 With the option enabled the kernel parameter "nobp=0" or "nospec" 593 can be used to run the kernel in the normal branch prediction mode. 594 595 With the option disabled the modified branch prediction mode is 596 enabled with the "nobp=1" kernel parameter. 597 598 If unsure, say N. 599 600config EXPOLINE 601 def_bool n 602 prompt "Avoid speculative indirect branches in the kernel" 603 help 604 Compile the kernel with the expoline compiler options to guard 605 against kernel-to-user data leaks by avoiding speculative indirect 606 branches. 607 Requires a compiler with -mindirect-branch=thunk support for full 608 protection. The kernel may run slower. 609 610 If unsure, say N. 611 612choice 613 prompt "Expoline default" 614 depends on EXPOLINE 615 default EXPOLINE_FULL 616 617config EXPOLINE_OFF 618 bool "spectre_v2=off" 619 620config EXPOLINE_AUTO 621 bool "spectre_v2=auto" 622 623config EXPOLINE_FULL 624 bool "spectre_v2=on" 625 626endchoice 627 628config RELOCATABLE 629 bool "Build a relocatable kernel" 630 select MODULE_REL_CRCS if MODVERSIONS 631 default y 632 help 633 This builds a kernel image that retains relocation information 634 so it can be loaded at an arbitrary address. 635 The kernel is linked as a position-independent executable (PIE) 636 and contains dynamic relocations which are processed early in the 637 bootup process. 638 The relocations make the kernel image about 15% larger (compressed 639 10%), but are discarded at runtime. 640 641config RANDOMIZE_BASE 642 bool "Randomize the address of the kernel image (KASLR)" 643 depends on RELOCATABLE 644 default y 645 help 646 In support of Kernel Address Space Layout Randomization (KASLR), 647 this randomizes the address at which the kernel image is loaded, 648 as a security feature that deters exploit attempts relying on 649 knowledge of the location of kernel internals. 650 651endmenu 652 653menu "Memory setup" 654 655config ARCH_SPARSEMEM_ENABLE 656 def_bool y 657 select SPARSEMEM_VMEMMAP_ENABLE 658 select SPARSEMEM_VMEMMAP 659 660config ARCH_SPARSEMEM_DEFAULT 661 def_bool y 662 663config ARCH_SELECT_MEMORY_MODEL 664 def_bool y 665 666config ARCH_ENABLE_MEMORY_HOTPLUG 667 def_bool y if SPARSEMEM 668 669config ARCH_ENABLE_MEMORY_HOTREMOVE 670 def_bool y 671 672config ARCH_ENABLE_SPLIT_PMD_PTLOCK 673 def_bool y 674 675config FORCE_MAX_ZONEORDER 676 int 677 default "9" 678 679config MAX_PHYSMEM_BITS 680 int "Maximum size of supported physical memory in bits (42-53)" 681 range 42 53 682 default "46" 683 help 684 This option specifies the maximum supported size of physical memory 685 in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB). 686 Increasing the number of bits also increases the kernel image size. 687 By default 46 bits (64TB) are supported. 688 689config PACK_STACK 690 def_bool y 691 prompt "Pack kernel stack" 692 help 693 This option enables the compiler option -mkernel-backchain if it 694 is available. If the option is available the compiler supports 695 the new stack layout which dramatically reduces the minimum stack 696 frame size. With an old compiler a non-leaf function needs a 697 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With 698 -mkernel-backchain the minimum size drops to 16 byte on 31 bit 699 and 24 byte on 64 bit. 700 701 Say Y if you are unsure. 702 703config CHECK_STACK 704 def_bool y 705 depends on !VMAP_STACK 706 prompt "Detect kernel stack overflow" 707 help 708 This option enables the compiler option -mstack-guard and 709 -mstack-size if they are available. If the compiler supports them 710 it will emit additional code to each function prolog to trigger 711 an illegal operation if the kernel stack is about to overflow. 712 713 Say N if you are unsure. 714 715config STACK_GUARD 716 int "Size of the guard area (128-1024)" 717 range 128 1024 718 depends on CHECK_STACK 719 default "256" 720 help 721 This allows you to specify the size of the guard area at the lower 722 end of the kernel stack. If the kernel stack points into the guard 723 area on function entry an illegal operation is triggered. The size 724 needs to be a power of 2. Please keep in mind that the size of an 725 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit. 726 The minimum size for the stack guard should be 256 for 31 bit and 727 512 for 64 bit. 728 729config WARN_DYNAMIC_STACK 730 def_bool n 731 prompt "Emit compiler warnings for function with dynamic stack usage" 732 help 733 This option enables the compiler option -mwarn-dynamicstack. If the 734 compiler supports this options generates warnings for functions 735 that dynamically allocate stack space using alloca. 736 737 Say N if you are unsure. 738 739endmenu 740 741menu "I/O subsystem" 742 743config QDIO 744 def_tristate y 745 prompt "QDIO support" 746 ---help--- 747 This driver provides the Queued Direct I/O base support for 748 IBM System z. 749 750 To compile this driver as a module, choose M here: the 751 module will be called qdio. 752 753 If unsure, say Y. 754 755if PCI 756 757config PCI_NR_FUNCTIONS 758 int "Maximum number of PCI functions (1-4096)" 759 range 1 4096 760 default "128" 761 help 762 This allows you to specify the maximum number of PCI functions which 763 this kernel will support. 764 765endif # PCI 766 767config HAS_IOMEM 768 def_bool PCI 769 770config CHSC_SCH 771 def_tristate m 772 prompt "Support for CHSC subchannels" 773 help 774 This driver allows usage of CHSC subchannels. A CHSC subchannel 775 is usually present on LPAR only. 776 The driver creates a device /dev/chsc, which may be used to 777 obtain I/O configuration information about the machine and 778 to issue asynchronous chsc commands (DANGEROUS). 779 You will usually only want to use this interface on a special 780 LPAR designated for system management. 781 782 To compile this driver as a module, choose M here: the 783 module will be called chsc_sch. 784 785 If unsure, say N. 786 787config SCM_BUS 788 def_bool y 789 prompt "SCM bus driver" 790 help 791 Bus driver for Storage Class Memory. 792 793config EADM_SCH 794 def_tristate m 795 prompt "Support for EADM subchannels" 796 depends on SCM_BUS 797 help 798 This driver allows usage of EADM subchannels. EADM subchannels act 799 as a communication vehicle for SCM increments. 800 801 To compile this driver as a module, choose M here: the 802 module will be called eadm_sch. 803 804config VFIO_CCW 805 def_tristate n 806 prompt "Support for VFIO-CCW subchannels" 807 depends on S390_CCW_IOMMU && VFIO_MDEV 808 help 809 This driver allows usage of I/O subchannels via VFIO-CCW. 810 811 To compile this driver as a module, choose M here: the 812 module will be called vfio_ccw. 813 814config VFIO_AP 815 def_tristate n 816 prompt "VFIO support for AP devices" 817 depends on S390_AP_IOMMU && VFIO_MDEV_DEVICE && KVM 818 help 819 This driver grants access to Adjunct Processor (AP) devices 820 via the VFIO mediated device interface. 821 822 To compile this driver as a module, choose M here: the module 823 will be called vfio_ap. 824 825endmenu 826 827menu "Dump support" 828 829config CRASH_DUMP 830 bool "kernel crash dumps" 831 depends on SMP 832 select KEXEC 833 help 834 Generate crash dump after being started by kexec. 835 Crash dump kernels are loaded in the main kernel with kexec-tools 836 into a specially reserved region and then later executed after 837 a crash by kdump/kexec. 838 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this. 839 This option also enables s390 zfcpdump. 840 See also <file:Documentation/s390/zfcpdump.txt> 841 842endmenu 843 844config SECCOMP 845 def_bool y 846 prompt "Enable seccomp to safely compute untrusted bytecode" 847 depends on PROC_FS 848 help 849 This kernel feature is useful for number crunching applications 850 that may need to compute untrusted bytecode during their 851 execution. By using pipes or other transports made available to 852 the process as file descriptors supporting the read/write 853 syscalls, it's possible to isolate those applications in 854 their own address space using seccomp. Once seccomp is 855 enabled via /proc/<pid>/seccomp, it cannot be disabled 856 and the task is only allowed to execute a few safe syscalls 857 defined by each seccomp mode. 858 859 If unsure, say Y. 860 861menu "Power Management" 862 863config ARCH_HIBERNATION_POSSIBLE 864 def_bool y 865 866source "kernel/power/Kconfig" 867 868endmenu 869 870config CCW 871 def_bool y 872 873config HAVE_PNETID 874 tristate 875 default (SMC || CCWGROUP) 876 877menu "Virtualization" 878 879config PROTECTED_VIRTUALIZATION_GUEST 880 def_bool n 881 prompt "Protected virtualization guest support" 882 help 883 Select this option, if you want to be able to run this 884 kernel as a protected virtualization KVM guest. 885 Protected virtualization capable machines have a mini hypervisor 886 located at machine level (an ultravisor). With help of the 887 Ultravisor, KVM will be able to run "protected" VMs, special 888 VMs whose memory and management data are unavailable to KVM. 889 890config PFAULT 891 def_bool y 892 prompt "Pseudo page fault support" 893 help 894 Select this option, if you want to use PFAULT pseudo page fault 895 handling under VM. If running native or in LPAR, this option 896 has no effect. If your VM does not support PFAULT, PAGEEX 897 pseudo page fault handling will be used. 898 Note that VM 4.2 supports PFAULT but has a bug in its 899 implementation that causes some problems. 900 Everybody who wants to run Linux under VM != VM4.2 should select 901 this option. 902 903config CMM 904 def_tristate n 905 prompt "Cooperative memory management" 906 help 907 Select this option, if you want to enable the kernel interface 908 to reduce the memory size of the system. This is accomplished 909 by allocating pages of memory and put them "on hold". This only 910 makes sense for a system running under VM where the unused pages 911 will be reused by VM for other guest systems. The interface 912 allows an external monitor to balance memory of many systems. 913 Everybody who wants to run Linux under VM should select this 914 option. 915 916config CMM_IUCV 917 def_bool y 918 prompt "IUCV special message interface to cooperative memory management" 919 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV) 920 help 921 Select this option to enable the special message interface to 922 the cooperative memory management. 923 924config APPLDATA_BASE 925 def_bool n 926 prompt "Linux - VM Monitor Stream, base infrastructure" 927 depends on PROC_FS 928 help 929 This provides a kernel interface for creating and updating z/VM APPLDATA 930 monitor records. The monitor records are updated at certain time 931 intervals, once the timer is started. 932 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer, 933 i.e. enables or disables monitoring on the Linux side. 934 A custom interval value (in seconds) can be written to 935 /proc/appldata/interval. 936 937 Defaults are 60 seconds interval and timer off. 938 The /proc entries can also be read from, showing the current settings. 939 940config APPLDATA_MEM 941 def_tristate m 942 prompt "Monitor memory management statistics" 943 depends on APPLDATA_BASE && VM_EVENT_COUNTERS 944 help 945 This provides memory management related data to the Linux - VM Monitor 946 Stream, like paging/swapping rate, memory utilisation, etc. 947 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM 948 APPLDATA monitor record, i.e. enables or disables monitoring this record 949 on the z/VM side. 950 951 Default is disabled. 952 The /proc entry can also be read from, showing the current settings. 953 954 This can also be compiled as a module, which will be called 955 appldata_mem.o. 956 957config APPLDATA_OS 958 def_tristate m 959 prompt "Monitor OS statistics" 960 depends on APPLDATA_BASE 961 help 962 This provides OS related data to the Linux - VM Monitor Stream, like 963 CPU utilisation, etc. 964 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM 965 APPLDATA monitor record, i.e. enables or disables monitoring this record 966 on the z/VM side. 967 968 Default is disabled. 969 This can also be compiled as a module, which will be called 970 appldata_os.o. 971 972config APPLDATA_NET_SUM 973 def_tristate m 974 prompt "Monitor overall network statistics" 975 depends on APPLDATA_BASE && NET 976 help 977 This provides network related data to the Linux - VM Monitor Stream, 978 currently there is only a total sum of network I/O statistics, no 979 per-interface data. 980 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM 981 APPLDATA monitor record, i.e. enables or disables monitoring this record 982 on the z/VM side. 983 984 Default is disabled. 985 This can also be compiled as a module, which will be called 986 appldata_net_sum.o. 987 988config S390_HYPFS_FS 989 def_bool y 990 prompt "s390 hypervisor file system support" 991 select SYS_HYPERVISOR 992 help 993 This is a virtual file system intended to provide accounting 994 information in an s390 hypervisor environment. 995 996source "arch/s390/kvm/Kconfig" 997 998config S390_GUEST 999 def_bool y 1000 prompt "s390 support for virtio devices" 1001 select TTY 1002 select VIRTUALIZATION 1003 select VIRTIO 1004 select VIRTIO_CONSOLE 1005 help 1006 Enabling this option adds support for virtio based paravirtual device 1007 drivers on s390. 1008 1009 Select this option if you want to run the kernel as a guest under 1010 the KVM hypervisor. 1011 1012endmenu 1013