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 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_KEEP_MEMBLOCK 104 select ARCH_SAVE_PAGE_KEYS if HIBERNATION 105 select ARCH_SUPPORTS_ATOMIC_RMW 106 select ARCH_SUPPORTS_NUMA_BALANCING 107 select ARCH_USE_BUILTIN_BSWAP 108 select ARCH_USE_CMPXCHG_LOCKREF 109 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 110 select ARCH_WANT_IPC_PARSE_VERSION 111 select BUILDTIME_EXTABLE_SORT 112 select CLONE_BACKWARDS2 113 select DYNAMIC_FTRACE if FUNCTION_TRACER 114 select GENERIC_CLOCKEVENTS 115 select GENERIC_CPU_AUTOPROBE 116 select GENERIC_CPU_DEVICES if !SMP 117 select GENERIC_CPU_VULNERABILITIES 118 select GENERIC_FIND_FIRST_BIT 119 select GENERIC_SMP_IDLE_THREAD 120 select GENERIC_TIME_VSYSCALL 121 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 122 select HAVE_ARCH_AUDITSYSCALL 123 select HAVE_ARCH_JUMP_LABEL 124 select HAVE_ARCH_JUMP_LABEL_RELATIVE 125 select HAVE_ARCH_KASAN 126 select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES 127 select HAVE_ARCH_SECCOMP_FILTER 128 select HAVE_ARCH_SOFT_DIRTY 129 select HAVE_ARCH_TRACEHOOK 130 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 131 select HAVE_ARCH_VMAP_STACK 132 select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES 133 select HAVE_CMPXCHG_DOUBLE 134 select HAVE_CMPXCHG_LOCAL 135 select HAVE_COPY_THREAD_TLS 136 select HAVE_DEBUG_KMEMLEAK 137 select HAVE_DMA_CONTIGUOUS 138 select HAVE_DYNAMIC_FTRACE 139 select HAVE_DYNAMIC_FTRACE_WITH_REGS 140 select HAVE_EFFICIENT_UNALIGNED_ACCESS 141 select HAVE_FENTRY 142 select HAVE_FTRACE_MCOUNT_RECORD 143 select HAVE_FUNCTION_GRAPH_TRACER 144 select HAVE_FUNCTION_TRACER 145 select HAVE_FUTEX_CMPXCHG if FUTEX 146 select HAVE_GCC_PLUGINS 147 select HAVE_GENERIC_GUP 148 select HAVE_KERNEL_BZIP2 149 select HAVE_KERNEL_GZIP 150 select HAVE_KERNEL_LZ4 151 select HAVE_KERNEL_LZMA 152 select HAVE_KERNEL_LZO 153 select HAVE_KERNEL_UNCOMPRESSED 154 select HAVE_KERNEL_XZ 155 select HAVE_KPROBES 156 select HAVE_KRETPROBES 157 select HAVE_KVM 158 select HAVE_LIVEPATCH 159 select HAVE_PERF_REGS 160 select HAVE_PERF_USER_STACK_DUMP 161 select HAVE_MEMBLOCK_NODE_MAP 162 select HAVE_MEMBLOCK_PHYS_MAP 163 select HAVE_MMU_GATHER_NO_GATHER 164 select HAVE_MOD_ARCH_SPECIFIC 165 select HAVE_NOP_MCOUNT 166 select HAVE_OPROFILE 167 select HAVE_PCI 168 select HAVE_PERF_EVENTS 169 select HAVE_RCU_TABLE_FREE 170 select HAVE_REGS_AND_STACK_ACCESS_API 171 select HAVE_RSEQ 172 select HAVE_SYSCALL_TRACEPOINTS 173 select HAVE_VIRT_CPU_ACCOUNTING 174 select IOMMU_HELPER if PCI 175 select IOMMU_SUPPORT if PCI 176 select MODULES_USE_ELF_RELA 177 select NEED_DMA_MAP_STATE if PCI 178 select NEED_SG_DMA_LENGTH if PCI 179 select OLD_SIGACTION 180 select OLD_SIGSUSPEND3 181 select PCI_DOMAINS if PCI 182 select PCI_MSI if PCI 183 select SPARSE_IRQ 184 select SYSCTL_EXCEPTION_TRACE 185 select THREAD_INFO_IN_TASK 186 select TTY 187 select VIRT_CPU_ACCOUNTING 188 select ARCH_HAS_SCALED_CPUTIME 189 select HAVE_NMI 190 191 192config SCHED_OMIT_FRAME_POINTER 193 def_bool y 194 195config PGTABLE_LEVELS 196 int 197 default 5 198 199source "kernel/livepatch/Kconfig" 200 201menu "Processor type and features" 202 203config HAVE_MARCH_Z900_FEATURES 204 def_bool n 205 206config HAVE_MARCH_Z990_FEATURES 207 def_bool n 208 select HAVE_MARCH_Z900_FEATURES 209 210config HAVE_MARCH_Z9_109_FEATURES 211 def_bool n 212 select HAVE_MARCH_Z990_FEATURES 213 214config HAVE_MARCH_Z10_FEATURES 215 def_bool n 216 select HAVE_MARCH_Z9_109_FEATURES 217 218config HAVE_MARCH_Z196_FEATURES 219 def_bool n 220 select HAVE_MARCH_Z10_FEATURES 221 222config HAVE_MARCH_ZEC12_FEATURES 223 def_bool n 224 select HAVE_MARCH_Z196_FEATURES 225 226config HAVE_MARCH_Z13_FEATURES 227 def_bool n 228 select HAVE_MARCH_ZEC12_FEATURES 229 230config HAVE_MARCH_Z14_FEATURES 231 def_bool n 232 select HAVE_MARCH_Z13_FEATURES 233 234choice 235 prompt "Processor type" 236 default MARCH_Z196 237 238config MARCH_Z900 239 bool "IBM zSeries model z800 and z900" 240 depends on !CC_IS_CLANG 241 select HAVE_MARCH_Z900_FEATURES 242 help 243 Select this to enable optimizations for model z800/z900 (2064 and 244 2066 series). This will enable some optimizations that are not 245 available on older ESA/390 (31 Bit) only CPUs. 246 247config MARCH_Z990 248 bool "IBM zSeries model z890 and z990" 249 depends on !CC_IS_CLANG 250 select HAVE_MARCH_Z990_FEATURES 251 help 252 Select this to enable optimizations for model z890/z990 (2084 and 253 2086 series). The kernel will be slightly faster but will not work 254 on older machines. 255 256config MARCH_Z9_109 257 bool "IBM System z9" 258 depends on !CC_IS_CLANG 259 select HAVE_MARCH_Z9_109_FEATURES 260 help 261 Select this to enable optimizations for IBM System z9 (2094 and 262 2096 series). The kernel will be slightly faster but will not work 263 on older machines. 264 265config MARCH_Z10 266 bool "IBM System z10" 267 select HAVE_MARCH_Z10_FEATURES 268 help 269 Select this to enable optimizations for IBM System z10 (2097 and 270 2098 series). The kernel will be slightly faster but will not work 271 on older machines. 272 273config MARCH_Z196 274 bool "IBM zEnterprise 114 and 196" 275 select HAVE_MARCH_Z196_FEATURES 276 help 277 Select this to enable optimizations for IBM zEnterprise 114 and 196 278 (2818 and 2817 series). The kernel will be slightly faster but will 279 not work on older machines. 280 281config MARCH_ZEC12 282 bool "IBM zBC12 and zEC12" 283 select HAVE_MARCH_ZEC12_FEATURES 284 help 285 Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and 286 2827 series). The kernel will be slightly faster but will not work on 287 older machines. 288 289config MARCH_Z13 290 bool "IBM z13s and z13" 291 select HAVE_MARCH_Z13_FEATURES 292 help 293 Select this to enable optimizations for IBM z13s and z13 (2965 and 294 2964 series). The kernel will be slightly faster but will not work on 295 older machines. 296 297config MARCH_Z14 298 bool "IBM z14 ZR1 and z14" 299 select HAVE_MARCH_Z14_FEATURES 300 help 301 Select this to enable optimizations for IBM z14 ZR1 and z14 (3907 302 and 3906 series). The kernel will be slightly faster but will not 303 work on older machines. 304 305endchoice 306 307config MARCH_Z900_TUNE 308 def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT 309 310config MARCH_Z990_TUNE 311 def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT 312 313config MARCH_Z9_109_TUNE 314 def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT 315 316config MARCH_Z10_TUNE 317 def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT 318 319config MARCH_Z196_TUNE 320 def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT 321 322config MARCH_ZEC12_TUNE 323 def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT 324 325config MARCH_Z13_TUNE 326 def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT 327 328config MARCH_Z14_TUNE 329 def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT 330 331choice 332 prompt "Tune code generation" 333 default TUNE_DEFAULT 334 help 335 Cause the compiler to tune (-mtune) the generated code for a machine. 336 This will make the code run faster on the selected machine but 337 somewhat slower on other machines. 338 This option only changes how the compiler emits instructions, not the 339 selection of instructions itself, so the resulting kernel will run on 340 all other machines. 341 342config TUNE_DEFAULT 343 bool "Default" 344 help 345 Tune the generated code for the target processor for which the kernel 346 will be compiled. 347 348config TUNE_Z900 349 bool "IBM zSeries model z800 and z900" 350 depends on !CC_IS_CLANG 351 352config TUNE_Z990 353 bool "IBM zSeries model z890 and z990" 354 depends on !CC_IS_CLANG 355 356config TUNE_Z9_109 357 bool "IBM System z9" 358 depends on !CC_IS_CLANG 359 360config TUNE_Z10 361 bool "IBM System z10" 362 363config TUNE_Z196 364 bool "IBM zEnterprise 114 and 196" 365 366config TUNE_ZEC12 367 bool "IBM zBC12 and zEC12" 368 369config TUNE_Z13 370 bool "IBM z13" 371 372config TUNE_Z14 373 bool "IBM z14" 374 375endchoice 376 377config 64BIT 378 def_bool y 379 380config COMPAT 381 def_bool y 382 prompt "Kernel support for 31 bit emulation" 383 select COMPAT_BINFMT_ELF if BINFMT_ELF 384 select ARCH_WANT_OLD_COMPAT_IPC 385 select COMPAT_OLD_SIGACTION 386 select HAVE_UID16 387 depends on MULTIUSER 388 help 389 Select this option if you want to enable your system kernel to 390 handle system-calls from ELF binaries for 31 bit ESA. This option 391 (and some other stuff like libraries and such) is needed for 392 executing 31 bit applications. It is safe to say "Y". 393 394config COMPAT_VDSO 395 def_bool COMPAT && !CC_IS_CLANG 396 397config SYSVIPC_COMPAT 398 def_bool y if COMPAT && SYSVIPC 399 400config SMP 401 def_bool y 402 prompt "Symmetric multi-processing support" 403 ---help--- 404 This enables support for systems with more than one CPU. If you have 405 a system with only one CPU, like most personal computers, say N. If 406 you have a system with more than one CPU, say Y. 407 408 If you say N here, the kernel will run on uni- and multiprocessor 409 machines, but will use only one CPU of a multiprocessor machine. If 410 you say Y here, the kernel will run on many, but not all, 411 uniprocessor machines. On a uniprocessor machine, the kernel 412 will run faster if you say N here. 413 414 See also the SMP-HOWTO available at 415 <http://www.tldp.org/docs.html#howto>. 416 417 Even if you don't know what to do here, say Y. 418 419config NR_CPUS 420 int "Maximum number of CPUs (2-512)" 421 range 2 512 422 depends on SMP 423 default "64" 424 help 425 This allows you to specify the maximum number of CPUs which this 426 kernel will support. The maximum supported value is 512 and the 427 minimum value which makes sense is 2. 428 429 This is purely to save memory - each supported CPU adds 430 approximately sixteen kilobytes to the kernel image. 431 432config HOTPLUG_CPU 433 def_bool y 434 prompt "Support for hot-pluggable CPUs" 435 depends on SMP 436 help 437 Say Y here to be able to turn CPUs off and on. CPUs 438 can be controlled through /sys/devices/system/cpu/cpu#. 439 Say N if you want to disable CPU hotplug. 440 441# Some NUMA nodes have memory ranges that span 442# other nodes. Even though a pfn is valid and 443# between a node's start and end pfns, it may not 444# reside on that node. See memmap_init_zone() 445# for details. <- They meant memory holes! 446config NODES_SPAN_OTHER_NODES 447 def_bool NUMA 448 449config NUMA 450 bool "NUMA support" 451 depends on SMP && SCHED_TOPOLOGY 452 default n 453 help 454 Enable NUMA support 455 456 This option adds NUMA support to the kernel. 457 458 An operation mode can be selected by appending 459 numa=<method> to the kernel command line. 460 461 The default behaviour is identical to appending numa=plain to 462 the command line. This will create just one node with all 463 available memory and all CPUs in it. 464 465config NODES_SHIFT 466 int "Maximum NUMA nodes (as a power of 2)" 467 range 1 10 468 depends on NUMA 469 default "4" 470 help 471 Specify the maximum number of NUMA nodes available on the target 472 system. Increases memory reserved to accommodate various tables. 473 474menu "Select NUMA modes" 475 depends on NUMA 476 477config NUMA_EMU 478 bool "NUMA emulation" 479 default y 480 help 481 Numa emulation mode will split the available system memory into 482 equal chunks which then are distributed over the configured number 483 of nodes in a round-robin manner. 484 485 The number of fake nodes is limited by the number of available memory 486 chunks (i.e. memory size / fake size) and the number of supported 487 nodes in the kernel. 488 489 The CPUs are assigned to the nodes in a way that partially respects 490 the original machine topology (if supported by the machine). 491 Fair distribution of the CPUs is not guaranteed. 492 493config EMU_SIZE 494 hex "NUMA emulation memory chunk size" 495 default 0x10000000 496 range 0x400000 0x100000000 497 depends on NUMA_EMU 498 help 499 Select the default size by which the memory is chopped and then 500 assigned to emulated NUMA nodes. 501 502 This can be overridden by specifying 503 504 emu_size=<n> 505 506 on the kernel command line where also suffixes K, M, G, and T are 507 supported. 508 509endmenu 510 511config SCHED_SMT 512 def_bool n 513 514config SCHED_MC 515 def_bool n 516 517config SCHED_BOOK 518 def_bool n 519 520config SCHED_DRAWER 521 def_bool n 522 523config SCHED_TOPOLOGY 524 def_bool y 525 prompt "Topology scheduler support" 526 depends on SMP 527 select SCHED_SMT 528 select SCHED_MC 529 select SCHED_BOOK 530 select SCHED_DRAWER 531 help 532 Topology scheduler support improves the CPU scheduler's decision 533 making when dealing with machines that have multi-threading, 534 multiple cores or multiple books. 535 536source "kernel/Kconfig.hz" 537 538config KEXEC 539 def_bool y 540 select KEXEC_CORE 541 542config KEXEC_FILE 543 bool "kexec file based system call" 544 select KEXEC_CORE 545 select BUILD_BIN2C 546 depends on CRYPTO 547 depends on CRYPTO_SHA256 548 depends on CRYPTO_SHA256_S390 549 help 550 Enable the kexec file based system call. In contrast to the normal 551 kexec system call this system call takes file descriptors for the 552 kernel and initramfs as arguments. 553 554config ARCH_HAS_KEXEC_PURGATORY 555 def_bool y 556 depends on KEXEC_FILE 557 558config KEXEC_VERIFY_SIG 559 bool "Verify kernel signature during kexec_file_load() syscall" 560 depends on KEXEC_FILE && SYSTEM_DATA_VERIFICATION 561 help 562 This option makes kernel signature verification mandatory for 563 the kexec_file_load() syscall. 564 565 In addition to that option, you need to enable signature 566 verification for the corresponding kernel image type being 567 loaded in order for this to work. 568 569config ARCH_RANDOM 570 def_bool y 571 prompt "s390 architectural random number generation API" 572 help 573 Enable the s390 architectural random number generation API 574 to provide random data for all consumers within the Linux 575 kernel. 576 577 When enabled the arch_random_* functions declared in linux/random.h 578 are implemented. The implementation is based on the s390 CPACF 579 instruction subfunction TRNG which provides a real true random 580 number generator. 581 582 If unsure, say Y. 583 584config KERNEL_NOBP 585 def_bool n 586 prompt "Enable modified branch prediction for the kernel by default" 587 help 588 If this option is selected the kernel will switch to a modified 589 branch prediction mode if the firmware interface is available. 590 The modified branch prediction mode improves the behaviour in 591 regard to speculative execution. 592 593 With the option enabled the kernel parameter "nobp=0" or "nospec" 594 can be used to run the kernel in the normal branch prediction mode. 595 596 With the option disabled the modified branch prediction mode is 597 enabled with the "nobp=1" kernel parameter. 598 599 If unsure, say N. 600 601config EXPOLINE 602 def_bool n 603 prompt "Avoid speculative indirect branches in the kernel" 604 help 605 Compile the kernel with the expoline compiler options to guard 606 against kernel-to-user data leaks by avoiding speculative indirect 607 branches. 608 Requires a compiler with -mindirect-branch=thunk support for full 609 protection. The kernel may run slower. 610 611 If unsure, say N. 612 613choice 614 prompt "Expoline default" 615 depends on EXPOLINE 616 default EXPOLINE_FULL 617 618config EXPOLINE_OFF 619 bool "spectre_v2=off" 620 621config EXPOLINE_AUTO 622 bool "spectre_v2=auto" 623 624config EXPOLINE_FULL 625 bool "spectre_v2=on" 626 627endchoice 628 629config RELOCATABLE 630 bool "Build a relocatable kernel" 631 select MODULE_REL_CRCS if MODVERSIONS 632 default y 633 help 634 This builds a kernel image that retains relocation information 635 so it can be loaded at an arbitrary address. 636 The kernel is linked as a position-independent executable (PIE) 637 and contains dynamic relocations which are processed early in the 638 bootup process. 639 The relocations make the kernel image about 15% larger (compressed 640 10%), but are discarded at runtime. 641 642config RANDOMIZE_BASE 643 bool "Randomize the address of the kernel image (KASLR)" 644 depends on RELOCATABLE 645 default y 646 help 647 In support of Kernel Address Space Layout Randomization (KASLR), 648 this randomizes the address at which the kernel image is loaded, 649 as a security feature that deters exploit attempts relying on 650 knowledge of the location of kernel internals. 651 652endmenu 653 654menu "Memory setup" 655 656config ARCH_SPARSEMEM_ENABLE 657 def_bool y 658 select SPARSEMEM_VMEMMAP_ENABLE 659 select SPARSEMEM_VMEMMAP 660 661config ARCH_SPARSEMEM_DEFAULT 662 def_bool y 663 664config ARCH_SELECT_MEMORY_MODEL 665 def_bool y 666 667config ARCH_ENABLE_MEMORY_HOTPLUG 668 def_bool y if SPARSEMEM 669 670config ARCH_ENABLE_MEMORY_HOTREMOVE 671 def_bool y 672 673config ARCH_ENABLE_SPLIT_PMD_PTLOCK 674 def_bool y 675 676config FORCE_MAX_ZONEORDER 677 int 678 default "9" 679 680config MAX_PHYSMEM_BITS 681 int "Maximum size of supported physical memory in bits (42-53)" 682 range 42 53 683 default "46" 684 help 685 This option specifies the maximum supported size of physical memory 686 in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB). 687 Increasing the number of bits also increases the kernel image size. 688 By default 46 bits (64TB) are supported. 689 690config PACK_STACK 691 def_bool y 692 prompt "Pack kernel stack" 693 help 694 This option enables the compiler option -mkernel-backchain if it 695 is available. If the option is available the compiler supports 696 the new stack layout which dramatically reduces the minimum stack 697 frame size. With an old compiler a non-leaf function needs a 698 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With 699 -mkernel-backchain the minimum size drops to 16 byte on 31 bit 700 and 24 byte on 64 bit. 701 702 Say Y if you are unsure. 703 704config CHECK_STACK 705 def_bool y 706 depends on !VMAP_STACK 707 prompt "Detect kernel stack overflow" 708 help 709 This option enables the compiler option -mstack-guard and 710 -mstack-size if they are available. If the compiler supports them 711 it will emit additional code to each function prolog to trigger 712 an illegal operation if the kernel stack is about to overflow. 713 714 Say N if you are unsure. 715 716config STACK_GUARD 717 int "Size of the guard area (128-1024)" 718 range 128 1024 719 depends on CHECK_STACK 720 default "256" 721 help 722 This allows you to specify the size of the guard area at the lower 723 end of the kernel stack. If the kernel stack points into the guard 724 area on function entry an illegal operation is triggered. The size 725 needs to be a power of 2. Please keep in mind that the size of an 726 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit. 727 The minimum size for the stack guard should be 256 for 31 bit and 728 512 for 64 bit. 729 730config WARN_DYNAMIC_STACK 731 def_bool n 732 prompt "Emit compiler warnings for function with dynamic stack usage" 733 help 734 This option enables the compiler option -mwarn-dynamicstack. If the 735 compiler supports this options generates warnings for functions 736 that dynamically allocate stack space using alloca. 737 738 Say N if you are unsure. 739 740endmenu 741 742menu "I/O subsystem" 743 744config QDIO 745 def_tristate y 746 prompt "QDIO support" 747 ---help--- 748 This driver provides the Queued Direct I/O base support for 749 IBM System z. 750 751 To compile this driver as a module, choose M here: the 752 module will be called qdio. 753 754 If unsure, say Y. 755 756if PCI 757 758config PCI_NR_FUNCTIONS 759 int "Maximum number of PCI functions (1-4096)" 760 range 1 4096 761 default "128" 762 help 763 This allows you to specify the maximum number of PCI functions which 764 this kernel will support. 765 766endif # PCI 767 768config HAS_IOMEM 769 def_bool PCI 770 771config CHSC_SCH 772 def_tristate m 773 prompt "Support for CHSC subchannels" 774 help 775 This driver allows usage of CHSC subchannels. A CHSC subchannel 776 is usually present on LPAR only. 777 The driver creates a device /dev/chsc, which may be used to 778 obtain I/O configuration information about the machine and 779 to issue asynchronous chsc commands (DANGEROUS). 780 You will usually only want to use this interface on a special 781 LPAR designated for system management. 782 783 To compile this driver as a module, choose M here: the 784 module will be called chsc_sch. 785 786 If unsure, say N. 787 788config SCM_BUS 789 def_bool y 790 prompt "SCM bus driver" 791 help 792 Bus driver for Storage Class Memory. 793 794config EADM_SCH 795 def_tristate m 796 prompt "Support for EADM subchannels" 797 depends on SCM_BUS 798 help 799 This driver allows usage of EADM subchannels. EADM subchannels act 800 as a communication vehicle for SCM increments. 801 802 To compile this driver as a module, choose M here: the 803 module will be called eadm_sch. 804 805config VFIO_CCW 806 def_tristate n 807 prompt "Support for VFIO-CCW subchannels" 808 depends on S390_CCW_IOMMU && VFIO_MDEV 809 help 810 This driver allows usage of I/O subchannels via VFIO-CCW. 811 812 To compile this driver as a module, choose M here: the 813 module will be called vfio_ccw. 814 815config VFIO_AP 816 def_tristate n 817 prompt "VFIO support for AP devices" 818 depends on S390_AP_IOMMU && VFIO_MDEV_DEVICE && KVM 819 help 820 This driver grants access to Adjunct Processor (AP) devices 821 via the VFIO mediated device interface. 822 823 To compile this driver as a module, choose M here: the module 824 will be called vfio_ap. 825 826endmenu 827 828menu "Dump support" 829 830config CRASH_DUMP 831 bool "kernel crash dumps" 832 depends on SMP 833 select KEXEC 834 help 835 Generate crash dump after being started by kexec. 836 Crash dump kernels are loaded in the main kernel with kexec-tools 837 into a specially reserved region and then later executed after 838 a crash by kdump/kexec. 839 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this. 840 This option also enables s390 zfcpdump. 841 See also <file:Documentation/s390/zfcpdump.txt> 842 843endmenu 844 845config SECCOMP 846 def_bool y 847 prompt "Enable seccomp to safely compute untrusted bytecode" 848 depends on PROC_FS 849 help 850 This kernel feature is useful for number crunching applications 851 that may need to compute untrusted bytecode during their 852 execution. By using pipes or other transports made available to 853 the process as file descriptors supporting the read/write 854 syscalls, it's possible to isolate those applications in 855 their own address space using seccomp. Once seccomp is 856 enabled via /proc/<pid>/seccomp, it cannot be disabled 857 and the task is only allowed to execute a few safe syscalls 858 defined by each seccomp mode. 859 860 If unsure, say Y. 861 862menu "Power Management" 863 864config ARCH_HIBERNATION_POSSIBLE 865 def_bool y 866 867source "kernel/power/Kconfig" 868 869endmenu 870 871config CCW 872 def_bool y 873 874config HAVE_PNETID 875 tristate 876 default (SMC || CCWGROUP) 877 878menu "Virtualization" 879 880config PROTECTED_VIRTUALIZATION_GUEST 881 def_bool n 882 prompt "Protected virtualization guest support" 883 help 884 Select this option, if you want to be able to run this 885 kernel as a protected virtualization KVM guest. 886 Protected virtualization capable machines have a mini hypervisor 887 located at machine level (an ultravisor). With help of the 888 Ultravisor, KVM will be able to run "protected" VMs, special 889 VMs whose memory and management data are unavailable to KVM. 890 891config PFAULT 892 def_bool y 893 prompt "Pseudo page fault support" 894 help 895 Select this option, if you want to use PFAULT pseudo page fault 896 handling under VM. If running native or in LPAR, this option 897 has no effect. If your VM does not support PFAULT, PAGEEX 898 pseudo page fault handling will be used. 899 Note that VM 4.2 supports PFAULT but has a bug in its 900 implementation that causes some problems. 901 Everybody who wants to run Linux under VM != VM4.2 should select 902 this option. 903 904config CMM 905 def_tristate n 906 prompt "Cooperative memory management" 907 help 908 Select this option, if you want to enable the kernel interface 909 to reduce the memory size of the system. This is accomplished 910 by allocating pages of memory and put them "on hold". This only 911 makes sense for a system running under VM where the unused pages 912 will be reused by VM for other guest systems. The interface 913 allows an external monitor to balance memory of many systems. 914 Everybody who wants to run Linux under VM should select this 915 option. 916 917config CMM_IUCV 918 def_bool y 919 prompt "IUCV special message interface to cooperative memory management" 920 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV) 921 help 922 Select this option to enable the special message interface to 923 the cooperative memory management. 924 925config APPLDATA_BASE 926 def_bool n 927 prompt "Linux - VM Monitor Stream, base infrastructure" 928 depends on PROC_FS 929 help 930 This provides a kernel interface for creating and updating z/VM APPLDATA 931 monitor records. The monitor records are updated at certain time 932 intervals, once the timer is started. 933 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer, 934 i.e. enables or disables monitoring on the Linux side. 935 A custom interval value (in seconds) can be written to 936 /proc/appldata/interval. 937 938 Defaults are 60 seconds interval and timer off. 939 The /proc entries can also be read from, showing the current settings. 940 941config APPLDATA_MEM 942 def_tristate m 943 prompt "Monitor memory management statistics" 944 depends on APPLDATA_BASE && VM_EVENT_COUNTERS 945 help 946 This provides memory management related data to the Linux - VM Monitor 947 Stream, like paging/swapping rate, memory utilisation, etc. 948 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM 949 APPLDATA monitor record, i.e. enables or disables monitoring this record 950 on the z/VM side. 951 952 Default is disabled. 953 The /proc entry can also be read from, showing the current settings. 954 955 This can also be compiled as a module, which will be called 956 appldata_mem.o. 957 958config APPLDATA_OS 959 def_tristate m 960 prompt "Monitor OS statistics" 961 depends on APPLDATA_BASE 962 help 963 This provides OS related data to the Linux - VM Monitor Stream, like 964 CPU utilisation, etc. 965 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM 966 APPLDATA monitor record, i.e. enables or disables monitoring this record 967 on the z/VM side. 968 969 Default is disabled. 970 This can also be compiled as a module, which will be called 971 appldata_os.o. 972 973config APPLDATA_NET_SUM 974 def_tristate m 975 prompt "Monitor overall network statistics" 976 depends on APPLDATA_BASE && NET 977 help 978 This provides network related data to the Linux - VM Monitor Stream, 979 currently there is only a total sum of network I/O statistics, no 980 per-interface data. 981 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM 982 APPLDATA monitor record, i.e. enables or disables monitoring this record 983 on the z/VM side. 984 985 Default is disabled. 986 This can also be compiled as a module, which will be called 987 appldata_net_sum.o. 988 989config S390_HYPFS_FS 990 def_bool y 991 prompt "s390 hypervisor file system support" 992 select SYS_HYPERVISOR 993 help 994 This is a virtual file system intended to provide accounting 995 information in an s390 hypervisor environment. 996 997source "arch/s390/kvm/Kconfig" 998 999config S390_GUEST 1000 def_bool y 1001 prompt "s390 support for virtio devices" 1002 select TTY 1003 select VIRTUALIZATION 1004 select VIRTIO 1005 select VIRTIO_CONSOLE 1006 help 1007 Enabling this option adds support for virtio based paravirtual device 1008 drivers on s390. 1009 1010 Select this option if you want to run the kernel as a guest under 1011 the KVM hypervisor. 1012 1013endmenu 1014