1b2441318SGreg Kroah-Hartman# SPDX-License-Identifier: GPL-2.0 2fb32e03fSMathieu Desnoyers# 3fb32e03fSMathieu Desnoyers# General architecture dependent options 4fb32e03fSMathieu Desnoyers# 5125e5645SMathieu Desnoyers 61572497cSChristoph Hellwig# 71572497cSChristoph Hellwig# Note: arch/$(SRCARCH)/Kconfig needs to be included first so that it can 81572497cSChristoph Hellwig# override the default values in this file. 91572497cSChristoph Hellwig# 101572497cSChristoph Hellwigsource "arch/$(SRCARCH)/Kconfig" 111572497cSChristoph Hellwig 1222471e13SRandy Dunlapmenu "General architecture-dependent options" 1322471e13SRandy Dunlap 14692f66f2SHari Bathiniconfig CRASH_CORE 15692f66f2SHari Bathini bool 16692f66f2SHari Bathini 172965faa5SDave Youngconfig KEXEC_CORE 18692f66f2SHari Bathini select CRASH_CORE 192965faa5SDave Young bool 202965faa5SDave Young 21175fca3bSSven Schnelleconfig KEXEC_ELF 22175fca3bSSven Schnelle bool 23175fca3bSSven Schnelle 24467d2782SThiago Jung Bauermannconfig HAVE_IMA_KEXEC 25467d2782SThiago Jung Bauermann bool 26467d2782SThiago Jung Bauermann 275e6e9852SChristoph Hellwigconfig SET_FS 285e6e9852SChristoph Hellwig bool 295e6e9852SChristoph Hellwig 3005736e4aSThomas Gleixnerconfig HOTPLUG_SMT 3105736e4aSThomas Gleixner bool 3205736e4aSThomas Gleixner 33142781e1SThomas Gleixnerconfig GENERIC_ENTRY 34142781e1SThomas Gleixner bool 35142781e1SThomas Gleixner 36125e5645SMathieu Desnoyersconfig OPROFILE 37b309a294SRobert Richter tristate "OProfile system profiling" 38125e5645SMathieu Desnoyers depends on PROFILING 39125e5645SMathieu Desnoyers depends on HAVE_OPROFILE 40d69d59f4SIngo Molnar select RING_BUFFER 419a5963ebSChristian Borntraeger select RING_BUFFER_ALLOW_SWAP 42125e5645SMathieu Desnoyers help 43125e5645SMathieu Desnoyers OProfile is a profiling system capable of profiling the 44125e5645SMathieu Desnoyers whole system, include the kernel, kernel modules, libraries, 45125e5645SMathieu Desnoyers and applications. 46125e5645SMathieu Desnoyers 47125e5645SMathieu Desnoyers If unsure, say N. 48125e5645SMathieu Desnoyers 494d4036e0SJason Yehconfig OPROFILE_EVENT_MULTIPLEX 504d4036e0SJason Yeh bool "OProfile multiplexing support (EXPERIMENTAL)" 514d4036e0SJason Yeh default n 524d4036e0SJason Yeh depends on OPROFILE && X86 534d4036e0SJason Yeh help 544d4036e0SJason Yeh The number of hardware counters is limited. The multiplexing 554d4036e0SJason Yeh feature enables OProfile to gather more events than counters 564d4036e0SJason Yeh are provided by the hardware. This is realized by switching 579332ef9dSMasahiro Yamada between events at a user specified time interval. 584d4036e0SJason Yeh 594d4036e0SJason Yeh If unsure, say N. 604d4036e0SJason Yeh 61125e5645SMathieu Desnoyersconfig HAVE_OPROFILE 629ba16087SJan Beulich bool 63125e5645SMathieu Desnoyers 64dcfce4a0SRobert Richterconfig OPROFILE_NMI_TIMER 65dcfce4a0SRobert Richter def_bool y 66af9feebeSAnton Blanchard depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64 67dcfce4a0SRobert Richter 68125e5645SMathieu Desnoyersconfig KPROBES 69125e5645SMathieu Desnoyers bool "Kprobes" 7005ed160eSMasami Hiramatsu depends on MODULES 71125e5645SMathieu Desnoyers depends on HAVE_KPROBES 7205ed160eSMasami Hiramatsu select KALLSYMS 73125e5645SMathieu Desnoyers help 74125e5645SMathieu Desnoyers Kprobes allows you to trap at almost any kernel address and 75125e5645SMathieu Desnoyers execute a callback function. register_kprobe() establishes 76125e5645SMathieu Desnoyers a probepoint and specifies the callback. Kprobes is useful 77125e5645SMathieu Desnoyers for kernel debugging, non-intrusive instrumentation and testing. 78125e5645SMathieu Desnoyers If in doubt, say "N". 79125e5645SMathieu Desnoyers 8045f81b1cSSteven Rostedtconfig JUMP_LABEL 81c5905afbSIngo Molnar bool "Optimize very unlikely/likely branches" 8245f81b1cSSteven Rostedt depends on HAVE_ARCH_JUMP_LABEL 83e9666d10SMasahiro Yamada depends on CC_HAS_ASM_GOTO 8445f81b1cSSteven Rostedt help 85c5905afbSIngo Molnar This option enables a transparent branch optimization that 86c5905afbSIngo Molnar makes certain almost-always-true or almost-always-false branch 87c5905afbSIngo Molnar conditions even cheaper to execute within the kernel. 8845f81b1cSSteven Rostedt 89c5905afbSIngo Molnar Certain performance-sensitive kernel code, such as trace points, 90c5905afbSIngo Molnar scheduler functionality, networking code and KVM have such 91c5905afbSIngo Molnar branches and include support for this optimization technique. 92c5905afbSIngo Molnar 93c5905afbSIngo Molnar If it is detected that the compiler has support for "asm goto", 94c5905afbSIngo Molnar the kernel will compile such branches with just a nop 95c5905afbSIngo Molnar instruction. When the condition flag is toggled to true, the 96c5905afbSIngo Molnar nop will be converted to a jump instruction to execute the 97c5905afbSIngo Molnar conditional block of instructions. 98c5905afbSIngo Molnar 99c5905afbSIngo Molnar This technique lowers overhead and stress on the branch prediction 100c5905afbSIngo Molnar of the processor and generally makes the kernel faster. The update 101c5905afbSIngo Molnar of the condition is slower, but those are always very rare. 102c5905afbSIngo Molnar 103c5905afbSIngo Molnar ( On 32-bit x86, the necessary options added to the compiler 104c5905afbSIngo Molnar flags may increase the size of the kernel slightly. ) 10545f81b1cSSteven Rostedt 1061987c947SPeter Zijlstraconfig STATIC_KEYS_SELFTEST 1071987c947SPeter Zijlstra bool "Static key selftest" 1081987c947SPeter Zijlstra depends on JUMP_LABEL 1091987c947SPeter Zijlstra help 1101987c947SPeter Zijlstra Boot time self-test of the branch patching code. 1111987c947SPeter Zijlstra 112f03c4129SPeter Zijlstraconfig STATIC_CALL_SELFTEST 113f03c4129SPeter Zijlstra bool "Static call selftest" 114f03c4129SPeter Zijlstra depends on HAVE_STATIC_CALL 115f03c4129SPeter Zijlstra help 116f03c4129SPeter Zijlstra Boot time self-test of the call patching code. 117f03c4129SPeter Zijlstra 118afd66255SMasami Hiramatsuconfig OPTPROBES 1195cc718b9SMasami Hiramatsu def_bool y 1205cc718b9SMasami Hiramatsu depends on KPROBES && HAVE_OPTPROBES 12101b1d88bSThomas Gleixner select TASKS_RCU if PREEMPTION 122afd66255SMasami Hiramatsu 123e7dbfe34SMasami Hiramatsuconfig KPROBES_ON_FTRACE 124e7dbfe34SMasami Hiramatsu def_bool y 125e7dbfe34SMasami Hiramatsu depends on KPROBES && HAVE_KPROBES_ON_FTRACE 126e7dbfe34SMasami Hiramatsu depends on DYNAMIC_FTRACE_WITH_REGS 127e7dbfe34SMasami Hiramatsu help 128e7dbfe34SMasami Hiramatsu If function tracer is enabled and the arch supports full 129e7dbfe34SMasami Hiramatsu passing of pt_regs to function tracing, then kprobes can 130e7dbfe34SMasami Hiramatsu optimize on top of function tracing. 131e7dbfe34SMasami Hiramatsu 1322b144498SSrikar Dronamrajuconfig UPROBES 13309294e31SDavid A. Long def_bool n 134e8f4aa60SAllen Pais depends on ARCH_SUPPORTS_UPROBES 1352b144498SSrikar Dronamraju help 1367b2d81d4SIngo Molnar Uprobes is the user-space counterpart to kprobes: they 1377b2d81d4SIngo Molnar enable instrumentation applications (such as 'perf probe') 1387b2d81d4SIngo Molnar to establish unintrusive probes in user-space binaries and 1397b2d81d4SIngo Molnar libraries, by executing handler functions when the probes 1407b2d81d4SIngo Molnar are hit by user-space applications. 1417b2d81d4SIngo Molnar 1427b2d81d4SIngo Molnar ( These probes come in the form of single-byte breakpoints, 1437b2d81d4SIngo Molnar managed by the kernel and kept transparent to the probed 1447b2d81d4SIngo Molnar application. ) 1452b144498SSrikar Dronamraju 14658340a07SJohannes Bergconfig HAVE_EFFICIENT_UNALIGNED_ACCESS 1479ba16087SJan Beulich bool 14858340a07SJohannes Berg help 14958340a07SJohannes Berg Some architectures are unable to perform unaligned accesses 15058340a07SJohannes Berg without the use of get_unaligned/put_unaligned. Others are 15158340a07SJohannes Berg unable to perform such accesses efficiently (e.g. trap on 15258340a07SJohannes Berg unaligned access and require fixing it up in the exception 15358340a07SJohannes Berg handler.) 15458340a07SJohannes Berg 15558340a07SJohannes Berg This symbol should be selected by an architecture if it can 15658340a07SJohannes Berg perform unaligned accesses efficiently to allow different 15758340a07SJohannes Berg code paths to be selected for these cases. Some network 15858340a07SJohannes Berg drivers, for example, could opt to not fix up alignment 15958340a07SJohannes Berg problems with received packets if doing so would not help 16058340a07SJohannes Berg much. 16158340a07SJohannes Berg 162c9b54d6fSMauro Carvalho Chehab See Documentation/core-api/unaligned-memory-access.rst for more 16358340a07SJohannes Berg information on the topic of unaligned memory accesses. 16458340a07SJohannes Berg 165cf66bb93SDavid Woodhouseconfig ARCH_USE_BUILTIN_BSWAP 166cf66bb93SDavid Woodhouse bool 167cf66bb93SDavid Woodhouse help 168cf66bb93SDavid Woodhouse Modern versions of GCC (since 4.4) have builtin functions 169cf66bb93SDavid Woodhouse for handling byte-swapping. Using these, instead of the old 170cf66bb93SDavid Woodhouse inline assembler that the architecture code provides in the 171cf66bb93SDavid Woodhouse __arch_bswapXX() macros, allows the compiler to see what's 172cf66bb93SDavid Woodhouse happening and offers more opportunity for optimisation. In 173cf66bb93SDavid Woodhouse particular, the compiler will be able to combine the byteswap 174cf66bb93SDavid Woodhouse with a nearby load or store and use load-and-swap or 175cf66bb93SDavid Woodhouse store-and-swap instructions if the architecture has them. It 176cf66bb93SDavid Woodhouse should almost *never* result in code which is worse than the 177cf66bb93SDavid Woodhouse hand-coded assembler in <asm/swab.h>. But just in case it 178cf66bb93SDavid Woodhouse does, the use of the builtins is optional. 179cf66bb93SDavid Woodhouse 180cf66bb93SDavid Woodhouse Any architecture with load-and-swap or store-and-swap 181cf66bb93SDavid Woodhouse instructions should set this. And it shouldn't hurt to set it 182cf66bb93SDavid Woodhouse on architectures that don't have such instructions. 183cf66bb93SDavid Woodhouse 1849edddaa2SAnanth N Mavinakayanahalliconfig KRETPROBES 1859edddaa2SAnanth N Mavinakayanahalli def_bool y 1869edddaa2SAnanth N Mavinakayanahalli depends on KPROBES && HAVE_KRETPROBES 1879edddaa2SAnanth N Mavinakayanahalli 1887c68af6eSAvi Kivityconfig USER_RETURN_NOTIFIER 1897c68af6eSAvi Kivity bool 1907c68af6eSAvi Kivity depends on HAVE_USER_RETURN_NOTIFIER 1917c68af6eSAvi Kivity help 1927c68af6eSAvi Kivity Provide a kernel-internal notification when a cpu is about to 1937c68af6eSAvi Kivity switch to user mode. 1947c68af6eSAvi Kivity 19528b2ee20SRik van Rielconfig HAVE_IOREMAP_PROT 1969ba16087SJan Beulich bool 19728b2ee20SRik van Riel 198125e5645SMathieu Desnoyersconfig HAVE_KPROBES 1999ba16087SJan Beulich bool 2009edddaa2SAnanth N Mavinakayanahalli 2019edddaa2SAnanth N Mavinakayanahalliconfig HAVE_KRETPROBES 2029ba16087SJan Beulich bool 20374bc7ceeSArthur Kepner 204afd66255SMasami Hiramatsuconfig HAVE_OPTPROBES 205afd66255SMasami Hiramatsu bool 206d314d74cSCong Wang 207e7dbfe34SMasami Hiramatsuconfig HAVE_KPROBES_ON_FTRACE 208e7dbfe34SMasami Hiramatsu bool 209e7dbfe34SMasami Hiramatsu 210540adea3SMasami Hiramatsuconfig HAVE_FUNCTION_ERROR_INJECTION 2119802d865SJosef Bacik bool 2129802d865SJosef Bacik 21342a0bb3fSPetr Mladekconfig HAVE_NMI 21442a0bb3fSPetr Mladek bool 21542a0bb3fSPetr Mladek 2161f5a4ad9SRoland McGrath# 2171f5a4ad9SRoland McGrath# An arch should select this if it provides all these things: 2181f5a4ad9SRoland McGrath# 2191f5a4ad9SRoland McGrath# task_pt_regs() in asm/processor.h or asm/ptrace.h 2201f5a4ad9SRoland McGrath# arch_has_single_step() if there is hardware single-step support 2211f5a4ad9SRoland McGrath# arch_has_block_step() if there is hardware block-step support 2221f5a4ad9SRoland McGrath# asm/syscall.h supplying asm-generic/syscall.h interface 2231f5a4ad9SRoland McGrath# linux/regset.h user_regset interfaces 2241f5a4ad9SRoland McGrath# CORE_DUMP_USE_REGSET #define'd in linux/elf.h 2251f5a4ad9SRoland McGrath# TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} 2261f5a4ad9SRoland McGrath# TIF_NOTIFY_RESUME calls tracehook_notify_resume() 2271f5a4ad9SRoland McGrath# signal delivery calls tracehook_signal_handler() 2281f5a4ad9SRoland McGrath# 2291f5a4ad9SRoland McGrathconfig HAVE_ARCH_TRACEHOOK 2309ba16087SJan Beulich bool 2311f5a4ad9SRoland McGrath 232c64be2bbSMarek Szyprowskiconfig HAVE_DMA_CONTIGUOUS 233c64be2bbSMarek Szyprowski bool 234c64be2bbSMarek Szyprowski 23529d5e047SThomas Gleixnerconfig GENERIC_SMP_IDLE_THREAD 23629d5e047SThomas Gleixner bool 23729d5e047SThomas Gleixner 238485cf5daSKevin Hilmanconfig GENERIC_IDLE_POLL_SETUP 239485cf5daSKevin Hilman bool 240485cf5daSKevin Hilman 2416974f0c4SDaniel Micayconfig ARCH_HAS_FORTIFY_SOURCE 2426974f0c4SDaniel Micay bool 2436974f0c4SDaniel Micay help 2446974f0c4SDaniel Micay An architecture should select this when it can successfully 2456974f0c4SDaniel Micay build and run with CONFIG_FORTIFY_SOURCE. 2466974f0c4SDaniel Micay 247d8ae8a37SChristoph Hellwig# 248d8ae8a37SChristoph Hellwig# Select if the arch provides a historic keepinit alias for the retain_initrd 249d8ae8a37SChristoph Hellwig# command line option 250d8ae8a37SChristoph Hellwig# 251d8ae8a37SChristoph Hellwigconfig ARCH_HAS_KEEPINITRD 252d8ae8a37SChristoph Hellwig bool 253d8ae8a37SChristoph Hellwig 254d2852a22SDaniel Borkmann# Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h 255d2852a22SDaniel Borkmannconfig ARCH_HAS_SET_MEMORY 256d2852a22SDaniel Borkmann bool 257d2852a22SDaniel Borkmann 258d253ca0cSRick Edgecombe# Select if arch has all set_direct_map_invalid/default() functions 259d253ca0cSRick Edgecombeconfig ARCH_HAS_SET_DIRECT_MAP 260d253ca0cSRick Edgecombe bool 261d253ca0cSRick Edgecombe 262c30700dbSChristoph Hellwig# 263fa7e2247SChristoph Hellwig# Select if the architecture provides the arch_dma_set_uncached symbol to 264fa7e2247SChristoph Hellwig# either provide an uncached segement alias for a DMA allocation, or 265fa7e2247SChristoph Hellwig# to remap the page tables in place. 266c30700dbSChristoph Hellwig# 267fa7e2247SChristoph Hellwigconfig ARCH_HAS_DMA_SET_UNCACHED 268c30700dbSChristoph Hellwig bool 269c30700dbSChristoph Hellwig 270999a5d12SChristoph Hellwig# 271999a5d12SChristoph Hellwig# Select if the architectures provides the arch_dma_clear_uncached symbol 272999a5d12SChristoph Hellwig# to undo an in-place page table remap for uncached access. 273999a5d12SChristoph Hellwig# 274999a5d12SChristoph Hellwigconfig ARCH_HAS_DMA_CLEAR_UNCACHED 275f5e10287SThomas Gleixner bool 276f5e10287SThomas Gleixner 2775905429aSKees Cook# Select if arch init_task must go in the __init_task_data section 2785905429aSKees Cookconfig ARCH_TASK_STRUCT_ON_STACK 2795905429aSKees Cook bool 2805905429aSKees Cook 2815905429aSKees Cook# Select if arch has its private alloc_task_struct() function 2825905429aSKees Cookconfig ARCH_TASK_STRUCT_ALLOCATOR 2835905429aSKees Cook bool 2845905429aSKees Cook 2855905429aSKees Cookconfig HAVE_ARCH_THREAD_STRUCT_WHITELIST 2865905429aSKees Cook bool 2875905429aSKees Cook depends on !ARCH_TASK_STRUCT_ALLOCATOR 288b235beeaSLinus Torvalds help 289b235beeaSLinus Torvalds An architecture should select this to provide hardened usercopy 290f5e10287SThomas Gleixner knowledge about what region of the thread_struct should be 291f5e10287SThomas Gleixner whitelisted for copying to userspace. Normally this is only the 2925aaeb5c0SIngo Molnar FPU registers. Specifically, arch_thread_struct_whitelist() 2935aaeb5c0SIngo Molnar should be implemented. Without this, the entire thread_struct 2945aaeb5c0SIngo Molnar field in task_struct will be left whitelisted. 2955aaeb5c0SIngo Molnar 296942fa985SYury Norov# Select if arch has its private alloc_thread_stack() function 297942fa985SYury Norovconfig ARCH_THREAD_STACK_ALLOCATOR 298942fa985SYury Norov bool 299942fa985SYury Norov 300942fa985SYury Norov# Select if arch wants to size task_struct dynamically via arch_task_struct_size: 301942fa985SYury Norovconfig ARCH_WANTS_DYNAMIC_TASK_STRUCT 302942fa985SYury Norov bool 303942fa985SYury Norov 304942fa985SYury Norovconfig ARCH_32BIT_OFF_T 305942fa985SYury Norov bool 306f850c30cSHeiko Carstens depends on !64BIT 307f850c30cSHeiko Carstens help 308e01292b1SHeiko Carstens All new 32-bit architectures should have 64-bit off_t type on 309e01292b1SHeiko Carstens userspace side which corresponds to the loff_t kernel type. This 310e01292b1SHeiko Carstens is the requirement for modern ABIs. Some existing architectures 311e01292b1SHeiko Carstens still support 32-bit off_t. This option is enabled for all such 312e01292b1SHeiko Carstens architectures explicitly. 313f850c30cSHeiko Carstens 3142ff2b7ecSMasahiro Yamadaconfig HAVE_ASM_MODVERSIONS 3152ff2b7ecSMasahiro Yamada bool 3162ff2b7ecSMasahiro Yamada help 3172ff2b7ecSMasahiro Yamada This symbol should be selected by an architecure if it provides 3182ff2b7ecSMasahiro Yamada <asm/asm-prototypes.h> to support the module versioning for symbols 3192ff2b7ecSMasahiro Yamada exported from assembly code. 3202ff2b7ecSMasahiro Yamada 3219483a578SDavid Brownellconfig HAVE_REGS_AND_STACK_ACCESS_API 3229ba16087SJan Beulich bool 3239483a578SDavid Brownell help 3249483a578SDavid Brownell This symbol should be selected by an architecure if it supports 3259483a578SDavid Brownell the API needed to access registers and stack entries from pt_regs, 3269483a578SDavid Brownell declared in asm/ptrace.h 3275ee00bd4SJoerg Roedel For example the kprobes-based event tracer needs this API. 3285ee00bd4SJoerg Roedel 329d7822b1eSMathieu Desnoyersconfig HAVE_RSEQ 330d7822b1eSMathieu Desnoyers bool 331d7822b1eSMathieu Desnoyers depends on HAVE_REGS_AND_STACK_ACCESS_API 332d7822b1eSMathieu Desnoyers help 333d7822b1eSMathieu Desnoyers This symbol should be selected by an architecture if it 334d7822b1eSMathieu Desnoyers supports an implementation of restartable sequences. 335d7822b1eSMathieu Desnoyers 3363c88ee19SMasami Hiramatsuconfig HAVE_FUNCTION_ARG_ACCESS_API 3373c88ee19SMasami Hiramatsu bool 3383c88ee19SMasami Hiramatsu help 3393c88ee19SMasami Hiramatsu This symbol should be selected by an architecure if it supports 3403c88ee19SMasami Hiramatsu the API needed to access function arguments from pt_regs, 3413c88ee19SMasami Hiramatsu declared in asm/ptrace.h 3423c88ee19SMasami Hiramatsu 34362a038d3SK.Prasadconfig HAVE_HW_BREAKPOINT 34462a038d3SK.Prasad bool 34599e8c5a3SFrederic Weisbecker depends on PERF_EVENTS 34662a038d3SK.Prasad 3470102752eSFrederic Weisbeckerconfig HAVE_MIXED_BREAKPOINTS_REGS 3480102752eSFrederic Weisbecker bool 3490102752eSFrederic Weisbecker depends on HAVE_HW_BREAKPOINT 3500102752eSFrederic Weisbecker help 3510102752eSFrederic Weisbecker Depending on the arch implementation of hardware breakpoints, 3520102752eSFrederic Weisbecker some of them have separate registers for data and instruction 3530102752eSFrederic Weisbecker breakpoints addresses, others have mixed registers to store 3540102752eSFrederic Weisbecker them but define the access type in a control register. 3550102752eSFrederic Weisbecker Select this option if your arch implements breakpoints under the 3560102752eSFrederic Weisbecker latter fashion. 3570102752eSFrederic Weisbecker 3587c68af6eSAvi Kivityconfig HAVE_USER_RETURN_NOTIFIER 3597c68af6eSAvi Kivity bool 360a1922ed6SIngo Molnar 361c01d4323SFrederic Weisbeckerconfig HAVE_PERF_EVENTS_NMI 362c01d4323SFrederic Weisbecker bool 36323637d47SFrederic Weisbecker help 36423637d47SFrederic Weisbecker System hardware can generate an NMI using the perf event 36523637d47SFrederic Weisbecker subsystem. Also has support for calculating CPU cycle events 36623637d47SFrederic Weisbecker to determine how many clock cycles in a given period. 367c01d4323SFrederic Weisbecker 36805a4a952SNicholas Pigginconfig HAVE_HARDLOCKUP_DETECTOR_PERF 36905a4a952SNicholas Piggin bool 37005a4a952SNicholas Piggin depends on HAVE_PERF_EVENTS_NMI 37105a4a952SNicholas Piggin help 37205a4a952SNicholas Piggin The arch chooses to use the generic perf-NMI-based hardlockup 37305a4a952SNicholas Piggin detector. Must define HAVE_PERF_EVENTS_NMI. 37405a4a952SNicholas Piggin 37505a4a952SNicholas Pigginconfig HAVE_NMI_WATCHDOG 37605a4a952SNicholas Piggin depends on HAVE_NMI 37705a4a952SNicholas Piggin bool 37805a4a952SNicholas Piggin help 37905a4a952SNicholas Piggin The arch provides a low level NMI watchdog. It provides 38005a4a952SNicholas Piggin asm/nmi.h, and defines its own arch_touch_nmi_watchdog(). 38105a4a952SNicholas Piggin 38205a4a952SNicholas Pigginconfig HAVE_HARDLOCKUP_DETECTOR_ARCH 38305a4a952SNicholas Piggin bool 38405a4a952SNicholas Piggin select HAVE_NMI_WATCHDOG 38505a4a952SNicholas Piggin help 38605a4a952SNicholas Piggin The arch chooses to provide its own hardlockup detector, which is 38705a4a952SNicholas Piggin a superset of the HAVE_NMI_WATCHDOG. It also conforms to config 38805a4a952SNicholas Piggin interfaces and parameters provided by hardlockup detector subsystem. 38905a4a952SNicholas Piggin 390c5e63197SJiri Olsaconfig HAVE_PERF_REGS 391c5e63197SJiri Olsa bool 392c5e63197SJiri Olsa help 393c5e63197SJiri Olsa Support selective register dumps for perf events. This includes 394c5e63197SJiri Olsa bit-mapping of each registers and a unique architecture id. 395c5e63197SJiri Olsa 396c5ebcedbSJiri Olsaconfig HAVE_PERF_USER_STACK_DUMP 397c5ebcedbSJiri Olsa bool 398c5ebcedbSJiri Olsa help 399c5ebcedbSJiri Olsa Support user stack dumps for perf event samples. This needs 400c5ebcedbSJiri Olsa access to the user stack pointer which is not unified across 401c5ebcedbSJiri Olsa architectures. 402c5ebcedbSJiri Olsa 403bf5438fcSJason Baronconfig HAVE_ARCH_JUMP_LABEL 404bf5438fcSJason Baron bool 405bf5438fcSJason Baron 40650ff18abSArd Biesheuvelconfig HAVE_ARCH_JUMP_LABEL_RELATIVE 40750ff18abSArd Biesheuvel bool 40850ff18abSArd Biesheuvel 4090d6e24d4SPeter Zijlstraconfig MMU_GATHER_TABLE_FREE 4100d6e24d4SPeter Zijlstra bool 4110d6e24d4SPeter Zijlstra 412ff2e6d72SPeter Zijlstraconfig MMU_GATHER_RCU_TABLE_FREE 41326723911SPeter Zijlstra bool 4140d6e24d4SPeter Zijlstra select MMU_GATHER_TABLE_FREE 41526723911SPeter Zijlstra 4163af4bd03SPeter Zijlstraconfig MMU_GATHER_PAGE_SIZE 417ed6a7935SPeter Zijlstra bool 418ed6a7935SPeter Zijlstra 41927796d03SPeter Zijlstraconfig MMU_GATHER_NO_RANGE 42027796d03SPeter Zijlstra bool 42127796d03SPeter Zijlstra 422580a586cSPeter Zijlstraconfig MMU_GATHER_NO_GATHER 423952a31c9SMartin Schwidefsky bool 4240d6e24d4SPeter Zijlstra depends on MMU_GATHER_TABLE_FREE 425952a31c9SMartin Schwidefsky 426d53c3dfbSNicholas Pigginconfig ARCH_WANT_IRQS_OFF_ACTIVATE_MM 427d53c3dfbSNicholas Piggin bool 428d53c3dfbSNicholas Piggin help 429d53c3dfbSNicholas Piggin Temporary select until all architectures can be converted to have 430d53c3dfbSNicholas Piggin irqs disabled over activate_mm. Architectures that do IPI based TLB 431d53c3dfbSNicholas Piggin shootdowns should enable this. 432d53c3dfbSNicholas Piggin 433df013ffbSHuang Yingconfig ARCH_HAVE_NMI_SAFE_CMPXCHG 434df013ffbSHuang Ying bool 435df013ffbSHuang Ying 43643570fd2SHeiko Carstensconfig HAVE_ALIGNED_STRUCT_PAGE 43743570fd2SHeiko Carstens bool 43843570fd2SHeiko Carstens help 43943570fd2SHeiko Carstens This makes sure that struct pages are double word aligned and that 44043570fd2SHeiko Carstens e.g. the SLUB allocator can perform double word atomic operations 44143570fd2SHeiko Carstens on a struct page for better performance. However selecting this 44243570fd2SHeiko Carstens might increase the size of a struct page by a word. 44343570fd2SHeiko Carstens 4444156153cSHeiko Carstensconfig HAVE_CMPXCHG_LOCAL 4454156153cSHeiko Carstens bool 4464156153cSHeiko Carstens 4472565409fSHeiko Carstensconfig HAVE_CMPXCHG_DOUBLE 4482565409fSHeiko Carstens bool 4492565409fSHeiko Carstens 45077e58496SPaul E. McKenneyconfig ARCH_WEAK_RELEASE_ACQUIRE 45177e58496SPaul E. McKenney bool 45277e58496SPaul E. McKenney 453c1d7e01dSWill Deaconconfig ARCH_WANT_IPC_PARSE_VERSION 454c1d7e01dSWill Deacon bool 455c1d7e01dSWill Deacon 456c1d7e01dSWill Deaconconfig ARCH_WANT_COMPAT_IPC_PARSE_VERSION 457c1d7e01dSWill Deacon bool 458c1d7e01dSWill Deacon 45948b25c43SChris Metcalfconfig ARCH_WANT_OLD_COMPAT_IPC 460c1d7e01dSWill Deacon select ARCH_WANT_COMPAT_IPC_PARSE_VERSION 46148b25c43SChris Metcalf bool 46248b25c43SChris Metcalf 463282a181bSYiFei Zhuconfig HAVE_ARCH_SECCOMP 464e2cfabdfSWill Drewry bool 465e2cfabdfSWill Drewry help 466282a181bSYiFei Zhu An arch should select this symbol to support seccomp mode 1 (the fixed 467282a181bSYiFei Zhu syscall policy), and must provide an overrides for __NR_seccomp_sigreturn, 468282a181bSYiFei Zhu and compat syscalls if the asm-generic/seccomp.h defaults need adjustment: 469282a181bSYiFei Zhu - __NR_seccomp_read_32 470282a181bSYiFei Zhu - __NR_seccomp_write_32 471282a181bSYiFei Zhu - __NR_seccomp_exit_32 472282a181bSYiFei Zhu - __NR_seccomp_sigreturn_32 473282a181bSYiFei Zhu 474282a181bSYiFei Zhuconfig HAVE_ARCH_SECCOMP_FILTER 475282a181bSYiFei Zhu bool 476282a181bSYiFei Zhu select HAVE_ARCH_SECCOMP 477282a181bSYiFei Zhu help 478fb0fadf9SWill Drewry An arch should select this symbol if it provides all of these things: 479282a181bSYiFei Zhu - all the requirements for HAVE_ARCH_SECCOMP 480bb6ea430SWill Drewry - syscall_get_arch() 481bb6ea430SWill Drewry - syscall_get_arguments() 482bb6ea430SWill Drewry - syscall_rollback() 483bb6ea430SWill Drewry - syscall_set_return_value() 484fb0fadf9SWill Drewry - SIGSYS siginfo_t support 485fb0fadf9SWill Drewry - secure_computing is called from a ptrace_event()-safe context 486fb0fadf9SWill Drewry - secure_computing return value is checked and a return value of -1 487fb0fadf9SWill Drewry results in the system call being skipped immediately. 48848dc92b9SKees Cook - seccomp syscall wired up 489e2cfabdfSWill Drewry 490282a181bSYiFei Zhuconfig SECCOMP 491282a181bSYiFei Zhu prompt "Enable seccomp to safely execute untrusted bytecode" 492282a181bSYiFei Zhu def_bool y 493282a181bSYiFei Zhu depends on HAVE_ARCH_SECCOMP 494282a181bSYiFei Zhu help 495282a181bSYiFei Zhu This kernel feature is useful for number crunching applications 496282a181bSYiFei Zhu that may need to handle untrusted bytecode during their 497282a181bSYiFei Zhu execution. By using pipes or other transports made available 498282a181bSYiFei Zhu to the process as file descriptors supporting the read/write 499282a181bSYiFei Zhu syscalls, it's possible to isolate those applications in their 500282a181bSYiFei Zhu own address space using seccomp. Once seccomp is enabled via 501282a181bSYiFei Zhu prctl(PR_SET_SECCOMP) or the seccomp() syscall, it cannot be 502282a181bSYiFei Zhu disabled and the task is only allowed to execute a few safe 503282a181bSYiFei Zhu syscalls defined by each seccomp mode. 504282a181bSYiFei Zhu 505282a181bSYiFei Zhu If unsure, say Y. 506282a181bSYiFei Zhu 507e2cfabdfSWill Drewryconfig SECCOMP_FILTER 508e2cfabdfSWill Drewry def_bool y 509e2cfabdfSWill Drewry depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET 510e2cfabdfSWill Drewry help 511e2cfabdfSWill Drewry Enable tasks to build secure computing environments defined 512e2cfabdfSWill Drewry in terms of Berkeley Packet Filter programs which implement 513e2cfabdfSWill Drewry task-defined system call filtering polices. 514e2cfabdfSWill Drewry 5155fb94e9cSMauro Carvalho Chehab See Documentation/userspace-api/seccomp_filter.rst for details. 516e2cfabdfSWill Drewry 517afaef01cSAlexander Popovconfig HAVE_ARCH_STACKLEAK 518afaef01cSAlexander Popov bool 519afaef01cSAlexander Popov help 520afaef01cSAlexander Popov An architecture should select this if it has the code which 521afaef01cSAlexander Popov fills the used part of the kernel stack with the STACKLEAK_POISON 522afaef01cSAlexander Popov value before returning from system calls. 523afaef01cSAlexander Popov 524d148eac0SMasahiro Yamadaconfig HAVE_STACKPROTECTOR 52519952a92SKees Cook bool 52619952a92SKees Cook help 52719952a92SKees Cook An arch should select this symbol if: 52819952a92SKees Cook - it has implemented a stack canary (e.g. __stack_chk_guard) 52919952a92SKees Cook 530050e9baaSLinus Torvaldsconfig STACKPROTECTOR 5312a61f474SMasahiro Yamada bool "Stack Protector buffer overflow detection" 532d148eac0SMasahiro Yamada depends on HAVE_STACKPROTECTOR 5332a61f474SMasahiro Yamada depends on $(cc-option,-fstack-protector) 5342a61f474SMasahiro Yamada default y 5358779657dSKees Cook help 5368779657dSKees Cook This option turns on the "stack-protector" GCC feature. This 53719952a92SKees Cook feature puts, at the beginning of functions, a canary value on 53819952a92SKees Cook the stack just before the return address, and validates 53919952a92SKees Cook the value just before actually returning. Stack based buffer 54019952a92SKees Cook overflows (that need to overwrite this return address) now also 54119952a92SKees Cook overwrite the canary, which gets detected and the attack is then 54219952a92SKees Cook neutralized via a kernel panic. 54319952a92SKees Cook 5448779657dSKees Cook Functions will have the stack-protector canary logic added if they 5458779657dSKees Cook have an 8-byte or larger character array on the stack. 5468779657dSKees Cook 54719952a92SKees Cook This feature requires gcc version 4.2 or above, or a distribution 5488779657dSKees Cook gcc with the feature backported ("-fstack-protector"). 5498779657dSKees Cook 5508779657dSKees Cook On an x86 "defconfig" build, this feature adds canary checks to 5518779657dSKees Cook about 3% of all kernel functions, which increases kernel code size 5528779657dSKees Cook by about 0.3%. 5538779657dSKees Cook 554050e9baaSLinus Torvaldsconfig STACKPROTECTOR_STRONG 5552a61f474SMasahiro Yamada bool "Strong Stack Protector" 556050e9baaSLinus Torvalds depends on STACKPROTECTOR 5572a61f474SMasahiro Yamada depends on $(cc-option,-fstack-protector-strong) 5582a61f474SMasahiro Yamada default y 5598779657dSKees Cook help 5608779657dSKees Cook Functions will have the stack-protector canary logic added in any 5618779657dSKees Cook of the following conditions: 5628779657dSKees Cook 5638779657dSKees Cook - local variable's address used as part of the right hand side of an 5648779657dSKees Cook assignment or function argument 5658779657dSKees Cook - local variable is an array (or union containing an array), 5668779657dSKees Cook regardless of array type or length 5678779657dSKees Cook - uses register local variables 5688779657dSKees Cook 5698779657dSKees Cook This feature requires gcc version 4.9 or above, or a distribution 5708779657dSKees Cook gcc with the feature backported ("-fstack-protector-strong"). 5718779657dSKees Cook 5728779657dSKees Cook On an x86 "defconfig" build, this feature adds canary checks to 5738779657dSKees Cook about 20% of all kernel functions, which increases the kernel code 5748779657dSKees Cook size by about 2%. 5758779657dSKees Cook 576d08b9f0cSSami Tolvanenconfig ARCH_SUPPORTS_SHADOW_CALL_STACK 577d08b9f0cSSami Tolvanen bool 578d08b9f0cSSami Tolvanen help 579d08b9f0cSSami Tolvanen An architecture should select this if it supports Clang's Shadow 580aa7a65aeSWill Deacon Call Stack and implements runtime support for shadow stack 581aa7a65aeSWill Deacon switching. 582d08b9f0cSSami Tolvanen 583d08b9f0cSSami Tolvanenconfig SHADOW_CALL_STACK 584d08b9f0cSSami Tolvanen bool "Clang Shadow Call Stack" 585d08b9f0cSSami Tolvanen depends on CC_IS_CLANG && ARCH_SUPPORTS_SHADOW_CALL_STACK 586ddc9863eSSami Tolvanen depends on DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER 587d08b9f0cSSami Tolvanen help 588d08b9f0cSSami Tolvanen This option enables Clang's Shadow Call Stack, which uses a 589d08b9f0cSSami Tolvanen shadow stack to protect function return addresses from being 590d08b9f0cSSami Tolvanen overwritten by an attacker. More information can be found in 591d08b9f0cSSami Tolvanen Clang's documentation: 592d08b9f0cSSami Tolvanen 593d08b9f0cSSami Tolvanen https://clang.llvm.org/docs/ShadowCallStack.html 594d08b9f0cSSami Tolvanen 595d08b9f0cSSami Tolvanen Note that security guarantees in the kernel differ from the 596d08b9f0cSSami Tolvanen ones documented for user space. The kernel must store addresses 597d08b9f0cSSami Tolvanen of shadow stacks in memory, which means an attacker capable of 598d08b9f0cSSami Tolvanen reading and writing arbitrary memory may be able to locate them 599d08b9f0cSSami Tolvanen and hijack control flow by modifying the stacks. 600d08b9f0cSSami Tolvanen 6010f60a8efSKees Cookconfig HAVE_ARCH_WITHIN_STACK_FRAMES 6020f60a8efSKees Cook bool 6030f60a8efSKees Cook help 6040f60a8efSKees Cook An architecture should select this if it can walk the kernel stack 6050f60a8efSKees Cook frames to determine if an object is part of either the arguments 6060f60a8efSKees Cook or local variables (i.e. that it excludes saved return addresses, 6070f60a8efSKees Cook and similar) by implementing an inline arch_within_stack_frames(), 6080f60a8efSKees Cook which is used by CONFIG_HARDENED_USERCOPY. 6090f60a8efSKees Cook 61091d1aa43SFrederic Weisbeckerconfig HAVE_CONTEXT_TRACKING 6112b1d5024SFrederic Weisbecker bool 6122b1d5024SFrederic Weisbecker help 61391d1aa43SFrederic Weisbecker Provide kernel/user boundaries probes necessary for subsystems 61491d1aa43SFrederic Weisbecker that need it, such as userspace RCU extended quiescent state. 615490f561bSFrederic Weisbecker Syscalls need to be wrapped inside user_exit()-user_enter(), either 616490f561bSFrederic Weisbecker optimized behind static key or through the slow path using TIF_NOHZ 617490f561bSFrederic Weisbecker flag. Exceptions handlers must be wrapped as well. Irqs are already 618490f561bSFrederic Weisbecker protected inside rcu_irq_enter/rcu_irq_exit() but preemption or signal 619490f561bSFrederic Weisbecker handling on irq exit still need to be protected. 620490f561bSFrederic Weisbecker 621*83c2da2eSFrederic Weisbeckerconfig HAVE_CONTEXT_TRACKING_OFFSTACK 622*83c2da2eSFrederic Weisbecker bool 623*83c2da2eSFrederic Weisbecker help 624*83c2da2eSFrederic Weisbecker Architecture neither relies on exception_enter()/exception_exit() 625*83c2da2eSFrederic Weisbecker nor on schedule_user(). Also preempt_schedule_notrace() and 626*83c2da2eSFrederic Weisbecker preempt_schedule_irq() can't be called in a preemptible section 627*83c2da2eSFrederic Weisbecker while context tracking is CONTEXT_USER. This feature reflects a sane 628*83c2da2eSFrederic Weisbecker entry implementation where the following requirements are met on 629*83c2da2eSFrederic Weisbecker critical entry code, ie: before user_exit() or after user_enter(): 630*83c2da2eSFrederic Weisbecker 631*83c2da2eSFrederic Weisbecker - Critical entry code isn't preemptible (or better yet: 632*83c2da2eSFrederic Weisbecker not interruptible). 633*83c2da2eSFrederic Weisbecker - No use of RCU read side critical sections, unless rcu_nmi_enter() 634*83c2da2eSFrederic Weisbecker got called. 635*83c2da2eSFrederic Weisbecker - No use of instrumentation, unless instrumentation_begin() got 636*83c2da2eSFrederic Weisbecker called. 637*83c2da2eSFrederic Weisbecker 638490f561bSFrederic Weisbeckerconfig HAVE_TIF_NOHZ 639490f561bSFrederic Weisbecker bool 640490f561bSFrederic Weisbecker help 641490f561bSFrederic Weisbecker Arch relies on TIF_NOHZ and syscall slow path to implement context 642490f561bSFrederic Weisbecker tracking calls to user_enter()/user_exit(). 6432b1d5024SFrederic Weisbecker 644b952741cSFrederic Weisbeckerconfig HAVE_VIRT_CPU_ACCOUNTING 645b952741cSFrederic Weisbecker bool 646b952741cSFrederic Weisbecker 64740565b5aSStanislaw Gruszkaconfig ARCH_HAS_SCALED_CPUTIME 64840565b5aSStanislaw Gruszka bool 64940565b5aSStanislaw Gruszka 650554b0004SKevin Hilmanconfig HAVE_VIRT_CPU_ACCOUNTING_GEN 651554b0004SKevin Hilman bool 652554b0004SKevin Hilman default y if 64BIT 653554b0004SKevin Hilman help 654554b0004SKevin Hilman With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. 655554b0004SKevin Hilman Before enabling this option, arch code must be audited 656554b0004SKevin Hilman to ensure there are no races in concurrent read/write of 657554b0004SKevin Hilman cputime_t. For example, reading/writing 64-bit cputime_t on 658554b0004SKevin Hilman some 32-bit arches may require multiple accesses, so proper 659554b0004SKevin Hilman locking is needed to protect against concurrent accesses. 660554b0004SKevin Hilman 661554b0004SKevin Hilman 662fdf9c356SFrederic Weisbeckerconfig HAVE_IRQ_TIME_ACCOUNTING 663fdf9c356SFrederic Weisbecker bool 664fdf9c356SFrederic Weisbecker help 665fdf9c356SFrederic Weisbecker Archs need to ensure they use a high enough resolution clock to 666fdf9c356SFrederic Weisbecker support irq time accounting and then call enable_sched_clock_irqtime(). 667fdf9c356SFrederic Weisbecker 6682c91bd4aSJoel Fernandes (Google)config HAVE_MOVE_PMD 6692c91bd4aSJoel Fernandes (Google) bool 6702c91bd4aSJoel Fernandes (Google) help 6712c91bd4aSJoel Fernandes (Google) Archs that select this are able to move page tables at the PMD level. 6722c91bd4aSJoel Fernandes (Google) 67315626062SGerald Schaeferconfig HAVE_ARCH_TRANSPARENT_HUGEPAGE 67415626062SGerald Schaefer bool 67515626062SGerald Schaefer 676a00cc7d9SMatthew Wilcoxconfig HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 677a00cc7d9SMatthew Wilcox bool 678a00cc7d9SMatthew Wilcox 6790ddab1d2SToshi Kaniconfig HAVE_ARCH_HUGE_VMAP 6800ddab1d2SToshi Kani bool 6810ddab1d2SToshi Kani 6823876d4a3SAlexandre Ghiticonfig ARCH_WANT_HUGE_PMD_SHARE 6833876d4a3SAlexandre Ghiti bool 6843876d4a3SAlexandre Ghiti 6850f8975ecSPavel Emelyanovconfig HAVE_ARCH_SOFT_DIRTY 6860f8975ecSPavel Emelyanov bool 6870f8975ecSPavel Emelyanov 688786d35d4SDavid Howellsconfig HAVE_MOD_ARCH_SPECIFIC 689786d35d4SDavid Howells bool 690786d35d4SDavid Howells help 691786d35d4SDavid Howells The arch uses struct mod_arch_specific to store data. Many arches 692786d35d4SDavid Howells just need a simple module loader without arch specific data - those 693786d35d4SDavid Howells should not enable this. 694786d35d4SDavid Howells 695786d35d4SDavid Howellsconfig MODULES_USE_ELF_RELA 696786d35d4SDavid Howells bool 697786d35d4SDavid Howells help 698786d35d4SDavid Howells Modules only use ELF RELA relocations. Modules with ELF REL 699786d35d4SDavid Howells relocations will give an error. 700786d35d4SDavid Howells 701786d35d4SDavid Howellsconfig MODULES_USE_ELF_REL 702786d35d4SDavid Howells bool 703786d35d4SDavid Howells help 704786d35d4SDavid Howells Modules only use ELF REL relocations. Modules with ELF RELA 705786d35d4SDavid Howells relocations will give an error. 706786d35d4SDavid Howells 707cc1f0274SFrederic Weisbeckerconfig HAVE_IRQ_EXIT_ON_IRQ_STACK 708cc1f0274SFrederic Weisbecker bool 709cc1f0274SFrederic Weisbecker help 710cc1f0274SFrederic Weisbecker Architecture doesn't only execute the irq handler on the irq stack 711cc1f0274SFrederic Weisbecker but also irq_exit(). This way we can process softirqs on this irq 712cc1f0274SFrederic Weisbecker stack instead of switching to a new one when we call __do_softirq() 713cc1f0274SFrederic Weisbecker in the end of an hardirq. 714cc1f0274SFrederic Weisbecker This spares a stack switch and improves cache usage on softirq 715cc1f0274SFrederic Weisbecker processing. 716cc1f0274SFrederic Weisbecker 717235a8f02SKirill A. Shutemovconfig PGTABLE_LEVELS 718235a8f02SKirill A. Shutemov int 719235a8f02SKirill A. Shutemov default 2 720235a8f02SKirill A. Shutemov 7212b68f6caSKees Cookconfig ARCH_HAS_ELF_RANDOMIZE 7222b68f6caSKees Cook bool 7232b68f6caSKees Cook help 7242b68f6caSKees Cook An architecture supports choosing randomized locations for 7252b68f6caSKees Cook stack, mmap, brk, and ET_DYN. Defined functions: 7262b68f6caSKees Cook - arch_mmap_rnd() 727204db6edSKees Cook - arch_randomize_brk() 7282b68f6caSKees Cook 729d07e2259SDaniel Cashmanconfig HAVE_ARCH_MMAP_RND_BITS 730d07e2259SDaniel Cashman bool 731d07e2259SDaniel Cashman help 732d07e2259SDaniel Cashman An arch should select this symbol if it supports setting a variable 733d07e2259SDaniel Cashman number of bits for use in establishing the base address for mmap 734d07e2259SDaniel Cashman allocations, has MMU enabled and provides values for both: 735d07e2259SDaniel Cashman - ARCH_MMAP_RND_BITS_MIN 736d07e2259SDaniel Cashman - ARCH_MMAP_RND_BITS_MAX 737d07e2259SDaniel Cashman 7385f56a5dfSJiri Slabyconfig HAVE_EXIT_THREAD 7395f56a5dfSJiri Slaby bool 7405f56a5dfSJiri Slaby help 7415f56a5dfSJiri Slaby An architecture implements exit_thread. 7425f56a5dfSJiri Slaby 743d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 744d07e2259SDaniel Cashman int 745d07e2259SDaniel Cashman 746d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 747d07e2259SDaniel Cashman int 748d07e2259SDaniel Cashman 749d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS_DEFAULT 750d07e2259SDaniel Cashman int 751d07e2259SDaniel Cashman 752d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS 753d07e2259SDaniel Cashman int "Number of bits to use for ASLR of mmap base address" if EXPERT 754d07e2259SDaniel Cashman range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX 755d07e2259SDaniel Cashman default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT 756d07e2259SDaniel Cashman default ARCH_MMAP_RND_BITS_MIN 757d07e2259SDaniel Cashman depends on HAVE_ARCH_MMAP_RND_BITS 758d07e2259SDaniel Cashman help 759d07e2259SDaniel Cashman This value can be used to select the number of bits to use to 760d07e2259SDaniel Cashman determine the random offset to the base address of vma regions 761d07e2259SDaniel Cashman resulting from mmap allocations. This value will be bounded 762d07e2259SDaniel Cashman by the architecture's minimum and maximum supported values. 763d07e2259SDaniel Cashman 764d07e2259SDaniel Cashman This value can be changed after boot using the 765d07e2259SDaniel Cashman /proc/sys/vm/mmap_rnd_bits tunable 766d07e2259SDaniel Cashman 767d07e2259SDaniel Cashmanconfig HAVE_ARCH_MMAP_RND_COMPAT_BITS 768d07e2259SDaniel Cashman bool 769d07e2259SDaniel Cashman help 770d07e2259SDaniel Cashman An arch should select this symbol if it supports running applications 771d07e2259SDaniel Cashman in compatibility mode, supports setting a variable number of bits for 772d07e2259SDaniel Cashman use in establishing the base address for mmap allocations, has MMU 773d07e2259SDaniel Cashman enabled and provides values for both: 774d07e2259SDaniel Cashman - ARCH_MMAP_RND_COMPAT_BITS_MIN 775d07e2259SDaniel Cashman - ARCH_MMAP_RND_COMPAT_BITS_MAX 776d07e2259SDaniel Cashman 777d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 778d07e2259SDaniel Cashman int 779d07e2259SDaniel Cashman 780d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 781d07e2259SDaniel Cashman int 782d07e2259SDaniel Cashman 783d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 784d07e2259SDaniel Cashman int 785d07e2259SDaniel Cashman 786d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS 787d07e2259SDaniel Cashman int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT 788d07e2259SDaniel Cashman range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX 789d07e2259SDaniel Cashman default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 790d07e2259SDaniel Cashman default ARCH_MMAP_RND_COMPAT_BITS_MIN 791d07e2259SDaniel Cashman depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS 792d07e2259SDaniel Cashman help 793d07e2259SDaniel Cashman This value can be used to select the number of bits to use to 794d07e2259SDaniel Cashman determine the random offset to the base address of vma regions 795d07e2259SDaniel Cashman resulting from mmap allocations for compatible applications This 796d07e2259SDaniel Cashman value will be bounded by the architecture's minimum and maximum 797d07e2259SDaniel Cashman supported values. 798d07e2259SDaniel Cashman 799d07e2259SDaniel Cashman This value can be changed after boot using the 800d07e2259SDaniel Cashman /proc/sys/vm/mmap_rnd_compat_bits tunable 801d07e2259SDaniel Cashman 8021b028f78SDmitry Safonovconfig HAVE_ARCH_COMPAT_MMAP_BASES 8031b028f78SDmitry Safonov bool 8041b028f78SDmitry Safonov help 8051b028f78SDmitry Safonov This allows 64bit applications to invoke 32-bit mmap() syscall 8061b028f78SDmitry Safonov and vice-versa 32-bit applications to call 64-bit mmap(). 8071b028f78SDmitry Safonov Required for applications doing different bitness syscalls. 8081b028f78SDmitry Safonov 80967f3977fSAlexandre Ghiti# This allows to use a set of generic functions to determine mmap base 81067f3977fSAlexandre Ghiti# address by giving priority to top-down scheme only if the process 81167f3977fSAlexandre Ghiti# is not in legacy mode (compat task, unlimited stack size or 81267f3977fSAlexandre Ghiti# sysctl_legacy_va_layout). 81367f3977fSAlexandre Ghiti# Architecture that selects this option can provide its own version of: 81467f3977fSAlexandre Ghiti# - STACK_RND_MASK 81567f3977fSAlexandre Ghiticonfig ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 81667f3977fSAlexandre Ghiti bool 81767f3977fSAlexandre Ghiti depends on MMU 818e7142bf5SAlexandre Ghiti select ARCH_HAS_ELF_RANDOMIZE 81967f3977fSAlexandre Ghiti 820b9ab5ebbSJosh Poimboeufconfig HAVE_STACK_VALIDATION 821b9ab5ebbSJosh Poimboeuf bool 822b9ab5ebbSJosh Poimboeuf help 823b9ab5ebbSJosh Poimboeuf Architecture supports the 'objtool check' host tool command, which 824b9ab5ebbSJosh Poimboeuf performs compile-time stack metadata validation. 825b9ab5ebbSJosh Poimboeuf 826af085d90SJosh Poimboeufconfig HAVE_RELIABLE_STACKTRACE 827af085d90SJosh Poimboeuf bool 828af085d90SJosh Poimboeuf help 829140d7e88SMiroslav Benes Architecture has either save_stack_trace_tsk_reliable() or 830140d7e88SMiroslav Benes arch_stack_walk_reliable() function which only returns a stack trace 831140d7e88SMiroslav Benes if it can guarantee the trace is reliable. 832af085d90SJosh Poimboeuf 833468a9428SGeorge Spelvinconfig HAVE_ARCH_HASH 834468a9428SGeorge Spelvin bool 835468a9428SGeorge Spelvin default n 836468a9428SGeorge Spelvin help 837468a9428SGeorge Spelvin If this is set, the architecture provides an <asm/hash.h> 838468a9428SGeorge Spelvin file which provides platform-specific implementations of some 839468a9428SGeorge Spelvin functions in <linux/hash.h> or fs/namei.c. 840468a9428SGeorge Spelvin 841666047feSFinn Thainconfig HAVE_ARCH_NVRAM_OPS 842666047feSFinn Thain bool 843666047feSFinn Thain 8443a495511SWilliam Breathitt Grayconfig ISA_BUS_API 8453a495511SWilliam Breathitt Gray def_bool ISA 8463a495511SWilliam Breathitt Gray 847d2125043SAl Viro# 848d2125043SAl Viro# ABI hall of shame 849d2125043SAl Viro# 850d2125043SAl Viroconfig CLONE_BACKWARDS 851d2125043SAl Viro bool 852d2125043SAl Viro help 853d2125043SAl Viro Architecture has tls passed as the 4th argument of clone(2), 854d2125043SAl Viro not the 5th one. 855d2125043SAl Viro 856d2125043SAl Viroconfig CLONE_BACKWARDS2 857d2125043SAl Viro bool 858d2125043SAl Viro help 859d2125043SAl Viro Architecture has the first two arguments of clone(2) swapped. 860d2125043SAl Viro 861dfa9771aSMichal Simekconfig CLONE_BACKWARDS3 862dfa9771aSMichal Simek bool 863dfa9771aSMichal Simek help 864dfa9771aSMichal Simek Architecture has tls passed as the 3rd argument of clone(2), 865dfa9771aSMichal Simek not the 5th one. 866dfa9771aSMichal Simek 867eaca6eaeSAl Viroconfig ODD_RT_SIGACTION 868eaca6eaeSAl Viro bool 869eaca6eaeSAl Viro help 870eaca6eaeSAl Viro Architecture has unusual rt_sigaction(2) arguments 871eaca6eaeSAl Viro 8720a0e8cdfSAl Viroconfig OLD_SIGSUSPEND 8730a0e8cdfSAl Viro bool 8740a0e8cdfSAl Viro help 8750a0e8cdfSAl Viro Architecture has old sigsuspend(2) syscall, of one-argument variety 8760a0e8cdfSAl Viro 8770a0e8cdfSAl Viroconfig OLD_SIGSUSPEND3 8780a0e8cdfSAl Viro bool 8790a0e8cdfSAl Viro help 8800a0e8cdfSAl Viro Even weirder antique ABI - three-argument sigsuspend(2) 8810a0e8cdfSAl Viro 882495dfbf7SAl Viroconfig OLD_SIGACTION 883495dfbf7SAl Viro bool 884495dfbf7SAl Viro help 885495dfbf7SAl Viro Architecture has old sigaction(2) syscall. Nope, not the same 886495dfbf7SAl Viro as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), 887495dfbf7SAl Viro but fairly different variant of sigaction(2), thanks to OSF/1 888495dfbf7SAl Viro compatibility... 889495dfbf7SAl Viro 890495dfbf7SAl Viroconfig COMPAT_OLD_SIGACTION 891495dfbf7SAl Viro bool 892495dfbf7SAl Viro 89317435e5fSDeepa Dinamaniconfig COMPAT_32BIT_TIME 894942437c9SArnd Bergmann bool "Provide system calls for 32-bit time_t" 895942437c9SArnd Bergmann default !64BIT || COMPAT 89617435e5fSDeepa Dinamani help 89717435e5fSDeepa Dinamani This enables 32 bit time_t support in addition to 64 bit time_t support. 89817435e5fSDeepa Dinamani This is relevant on all 32-bit architectures, and 64-bit architectures 89917435e5fSDeepa Dinamani as part of compat syscall handling. 90017435e5fSDeepa Dinamani 90187a4c375SChristoph Hellwigconfig ARCH_NO_PREEMPT 90287a4c375SChristoph Hellwig bool 90387a4c375SChristoph Hellwig 904a50a3f4bSThomas Gleixnerconfig ARCH_SUPPORTS_RT 905a50a3f4bSThomas Gleixner bool 906a50a3f4bSThomas Gleixner 907fff7fb0bSZhaoxiu Zengconfig CPU_NO_EFFICIENT_FFS 908fff7fb0bSZhaoxiu Zeng def_bool n 909fff7fb0bSZhaoxiu Zeng 910ba14a194SAndy Lutomirskiconfig HAVE_ARCH_VMAP_STACK 911ba14a194SAndy Lutomirski def_bool n 912ba14a194SAndy Lutomirski help 913ba14a194SAndy Lutomirski An arch should select this symbol if it can support kernel stacks 914ba14a194SAndy Lutomirski in vmalloc space. This means: 915ba14a194SAndy Lutomirski 916ba14a194SAndy Lutomirski - vmalloc space must be large enough to hold many kernel stacks. 917ba14a194SAndy Lutomirski This may rule out many 32-bit architectures. 918ba14a194SAndy Lutomirski 919ba14a194SAndy Lutomirski - Stacks in vmalloc space need to work reliably. For example, if 920ba14a194SAndy Lutomirski vmap page tables are created on demand, either this mechanism 921ba14a194SAndy Lutomirski needs to work while the stack points to a virtual address with 922ba14a194SAndy Lutomirski unpopulated page tables or arch code (switch_to() and switch_mm(), 923ba14a194SAndy Lutomirski most likely) needs to ensure that the stack's page table entries 924ba14a194SAndy Lutomirski are populated before running on a possibly unpopulated stack. 925ba14a194SAndy Lutomirski 926ba14a194SAndy Lutomirski - If the stack overflows into a guard page, something reasonable 927ba14a194SAndy Lutomirski should happen. The definition of "reasonable" is flexible, but 928ba14a194SAndy Lutomirski instantly rebooting without logging anything would be unfriendly. 929ba14a194SAndy Lutomirski 930ba14a194SAndy Lutomirskiconfig VMAP_STACK 931ba14a194SAndy Lutomirski default y 932ba14a194SAndy Lutomirski bool "Use a virtually-mapped stack" 933eafb149eSDaniel Axtens depends on HAVE_ARCH_VMAP_STACK 934eafb149eSDaniel Axtens depends on !KASAN || KASAN_VMALLOC 935a7f7f624SMasahiro Yamada help 936ba14a194SAndy Lutomirski Enable this if you want the use virtually-mapped kernel stacks 937ba14a194SAndy Lutomirski with guard pages. This causes kernel stack overflows to be 938ba14a194SAndy Lutomirski caught immediately rather than causing difficult-to-diagnose 939ba14a194SAndy Lutomirski corruption. 940ba14a194SAndy Lutomirski 941eafb149eSDaniel Axtens To use this with KASAN, the architecture must support backing 942eafb149eSDaniel Axtens virtual mappings with real shadow memory, and KASAN_VMALLOC must 943eafb149eSDaniel Axtens be enabled. 944ba14a194SAndy Lutomirski 945ad21fc4fSLaura Abbottconfig ARCH_OPTIONAL_KERNEL_RWX 946ad21fc4fSLaura Abbott def_bool n 947ad21fc4fSLaura Abbott 948ad21fc4fSLaura Abbottconfig ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 949ad21fc4fSLaura Abbott def_bool n 950ad21fc4fSLaura Abbott 951ad21fc4fSLaura Abbottconfig ARCH_HAS_STRICT_KERNEL_RWX 952ad21fc4fSLaura Abbott def_bool n 953ad21fc4fSLaura Abbott 9540f5bf6d0SLaura Abbottconfig STRICT_KERNEL_RWX 955ad21fc4fSLaura Abbott bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX 956ad21fc4fSLaura Abbott depends on ARCH_HAS_STRICT_KERNEL_RWX 957ad21fc4fSLaura Abbott default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 958ad21fc4fSLaura Abbott help 959ad21fc4fSLaura Abbott If this is set, kernel text and rodata memory will be made read-only, 960ad21fc4fSLaura Abbott and non-text memory will be made non-executable. This provides 961ad21fc4fSLaura Abbott protection against certain security exploits (e.g. executing the heap 962ad21fc4fSLaura Abbott or modifying text) 963ad21fc4fSLaura Abbott 964ad21fc4fSLaura Abbott These features are considered standard security practice these days. 965ad21fc4fSLaura Abbott You should say Y here in almost all cases. 966ad21fc4fSLaura Abbott 967ad21fc4fSLaura Abbottconfig ARCH_HAS_STRICT_MODULE_RWX 968ad21fc4fSLaura Abbott def_bool n 969ad21fc4fSLaura Abbott 9700f5bf6d0SLaura Abbottconfig STRICT_MODULE_RWX 971ad21fc4fSLaura Abbott bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX 972ad21fc4fSLaura Abbott depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES 973ad21fc4fSLaura Abbott default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 974ad21fc4fSLaura Abbott help 975ad21fc4fSLaura Abbott If this is set, module text and rodata memory will be made read-only, 976ad21fc4fSLaura Abbott and non-text memory will be made non-executable. This provides 977ad21fc4fSLaura Abbott protection against certain security exploits (e.g. writing to text) 978ad21fc4fSLaura Abbott 979ea8c64acSChristoph Hellwig# select if the architecture provides an asm/dma-direct.h header 980ea8c64acSChristoph Hellwigconfig ARCH_HAS_PHYS_TO_DMA 981ea8c64acSChristoph Hellwig bool 982ea8c64acSChristoph Hellwig 98304f264d3SPaul Burtonconfig HAVE_ARCH_COMPILER_H 98404f264d3SPaul Burton bool 98504f264d3SPaul Burton help 98604f264d3SPaul Burton An architecture can select this if it provides an 98704f264d3SPaul Burton asm/compiler.h header that should be included after 98804f264d3SPaul Burton linux/compiler-*.h in order to override macro definitions that those 98904f264d3SPaul Burton headers generally provide. 99004f264d3SPaul Burton 991271ca788SArd Biesheuvelconfig HAVE_ARCH_PREL32_RELOCATIONS 992271ca788SArd Biesheuvel bool 993271ca788SArd Biesheuvel help 994271ca788SArd Biesheuvel May be selected by an architecture if it supports place-relative 995271ca788SArd Biesheuvel 32-bit relocations, both in the toolchain and in the module loader, 996271ca788SArd Biesheuvel in which case relative references can be used in special sections 997271ca788SArd Biesheuvel for PCI fixup, initcalls etc which are only half the size on 64 bit 998271ca788SArd Biesheuvel architectures, and don't require runtime relocation on relocatable 999271ca788SArd Biesheuvel kernels. 1000271ca788SArd Biesheuvel 1001ce9084baSArd Biesheuvelconfig ARCH_USE_MEMREMAP_PROT 1002ce9084baSArd Biesheuvel bool 1003ce9084baSArd Biesheuvel 1004fb346fd9SWaiman Longconfig LOCK_EVENT_COUNTS 1005fb346fd9SWaiman Long bool "Locking event counts collection" 1006fb346fd9SWaiman Long depends on DEBUG_FS 1007a7f7f624SMasahiro Yamada help 1008fb346fd9SWaiman Long Enable light-weight counting of various locking related events 1009fb346fd9SWaiman Long in the system with minimal performance impact. This reduces 1010fb346fd9SWaiman Long the chance of application behavior change because of timing 1011fb346fd9SWaiman Long differences. The counts are reported via debugfs. 1012fb346fd9SWaiman Long 10135cf896fbSPeter Collingbourne# Select if the architecture has support for applying RELR relocations. 10145cf896fbSPeter Collingbourneconfig ARCH_HAS_RELR 10155cf896fbSPeter Collingbourne bool 10165cf896fbSPeter Collingbourne 10175cf896fbSPeter Collingbourneconfig RELR 10185cf896fbSPeter Collingbourne bool "Use RELR relocation packing" 10195cf896fbSPeter Collingbourne depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR 10205cf896fbSPeter Collingbourne default y 10215cf896fbSPeter Collingbourne help 10225cf896fbSPeter Collingbourne Store the kernel's dynamic relocations in the RELR relocation packing 10235cf896fbSPeter Collingbourne format. Requires a compatible linker (LLD supports this feature), as 10245cf896fbSPeter Collingbourne well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy 10255cf896fbSPeter Collingbourne are compatible). 10265cf896fbSPeter Collingbourne 10270c9c1d56SThiago Jung Bauermannconfig ARCH_HAS_MEM_ENCRYPT 10280c9c1d56SThiago Jung Bauermann bool 10290c9c1d56SThiago Jung Bauermann 10300e242208SHassan Naveedconfig HAVE_SPARSE_SYSCALL_NR 10310e242208SHassan Naveed bool 10320e242208SHassan Naveed help 10330e242208SHassan Naveed An architecture should select this if its syscall numbering is sparse 10340e242208SHassan Naveed to save space. For example, MIPS architecture has a syscall array with 10350e242208SHassan Naveed entries at 4000, 5000 and 6000 locations. This option turns on syscall 10360e242208SHassan Naveed related optimizations for a given architecture. 10370e242208SHassan Naveed 1038d60d7de3SSven Schnelleconfig ARCH_HAS_VDSO_DATA 1039d60d7de3SSven Schnelle bool 1040d60d7de3SSven Schnelle 1041115284d8SJosh Poimboeufconfig HAVE_STATIC_CALL 1042115284d8SJosh Poimboeuf bool 1043115284d8SJosh Poimboeuf 10449183c3f9SJosh Poimboeufconfig HAVE_STATIC_CALL_INLINE 10459183c3f9SJosh Poimboeuf bool 10469183c3f9SJosh Poimboeuf depends on HAVE_STATIC_CALL 10479183c3f9SJosh Poimboeuf 10482521f2c2SPeter Oberparleitersource "kernel/gcov/Kconfig" 104945332b1bSMasahiro Yamada 105045332b1bSMasahiro Yamadasource "scripts/gcc-plugins/Kconfig" 1051fa1b5d09SLinus Torvalds 105222471e13SRandy Dunlapendmenu 1053