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 21467d2782SThiago Jung Bauermannconfig HAVE_IMA_KEXEC 22467d2782SThiago Jung Bauermann bool 23467d2782SThiago Jung Bauermann 2405736e4aSThomas Gleixnerconfig HOTPLUG_SMT 2505736e4aSThomas Gleixner bool 2605736e4aSThomas Gleixner 27125e5645SMathieu Desnoyersconfig OPROFILE 28b309a294SRobert Richter tristate "OProfile system profiling" 29125e5645SMathieu Desnoyers depends on PROFILING 30125e5645SMathieu Desnoyers depends on HAVE_OPROFILE 31d69d59f4SIngo Molnar select RING_BUFFER 329a5963ebSChristian Borntraeger select RING_BUFFER_ALLOW_SWAP 33125e5645SMathieu Desnoyers help 34125e5645SMathieu Desnoyers OProfile is a profiling system capable of profiling the 35125e5645SMathieu Desnoyers whole system, include the kernel, kernel modules, libraries, 36125e5645SMathieu Desnoyers and applications. 37125e5645SMathieu Desnoyers 38125e5645SMathieu Desnoyers If unsure, say N. 39125e5645SMathieu Desnoyers 404d4036e0SJason Yehconfig OPROFILE_EVENT_MULTIPLEX 414d4036e0SJason Yeh bool "OProfile multiplexing support (EXPERIMENTAL)" 424d4036e0SJason Yeh default n 434d4036e0SJason Yeh depends on OPROFILE && X86 444d4036e0SJason Yeh help 454d4036e0SJason Yeh The number of hardware counters is limited. The multiplexing 464d4036e0SJason Yeh feature enables OProfile to gather more events than counters 474d4036e0SJason Yeh are provided by the hardware. This is realized by switching 489332ef9dSMasahiro Yamada between events at a user specified time interval. 494d4036e0SJason Yeh 504d4036e0SJason Yeh If unsure, say N. 514d4036e0SJason Yeh 52125e5645SMathieu Desnoyersconfig HAVE_OPROFILE 539ba16087SJan Beulich bool 54125e5645SMathieu Desnoyers 55dcfce4a0SRobert Richterconfig OPROFILE_NMI_TIMER 56dcfce4a0SRobert Richter def_bool y 57af9feebeSAnton Blanchard depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64 58dcfce4a0SRobert Richter 59125e5645SMathieu Desnoyersconfig KPROBES 60125e5645SMathieu Desnoyers bool "Kprobes" 6105ed160eSMasami Hiramatsu depends on MODULES 62125e5645SMathieu Desnoyers depends on HAVE_KPROBES 6305ed160eSMasami Hiramatsu select KALLSYMS 64125e5645SMathieu Desnoyers help 65125e5645SMathieu Desnoyers Kprobes allows you to trap at almost any kernel address and 66125e5645SMathieu Desnoyers execute a callback function. register_kprobe() establishes 67125e5645SMathieu Desnoyers a probepoint and specifies the callback. Kprobes is useful 68125e5645SMathieu Desnoyers for kernel debugging, non-intrusive instrumentation and testing. 69125e5645SMathieu Desnoyers If in doubt, say "N". 70125e5645SMathieu Desnoyers 7145f81b1cSSteven Rostedtconfig JUMP_LABEL 72c5905afbSIngo Molnar bool "Optimize very unlikely/likely branches" 7345f81b1cSSteven Rostedt depends on HAVE_ARCH_JUMP_LABEL 74e9666d10SMasahiro Yamada depends on CC_HAS_ASM_GOTO 7545f81b1cSSteven Rostedt help 76c5905afbSIngo Molnar This option enables a transparent branch optimization that 77c5905afbSIngo Molnar makes certain almost-always-true or almost-always-false branch 78c5905afbSIngo Molnar conditions even cheaper to execute within the kernel. 7945f81b1cSSteven Rostedt 80c5905afbSIngo Molnar Certain performance-sensitive kernel code, such as trace points, 81c5905afbSIngo Molnar scheduler functionality, networking code and KVM have such 82c5905afbSIngo Molnar branches and include support for this optimization technique. 83c5905afbSIngo Molnar 84c5905afbSIngo Molnar If it is detected that the compiler has support for "asm goto", 85c5905afbSIngo Molnar the kernel will compile such branches with just a nop 86c5905afbSIngo Molnar instruction. When the condition flag is toggled to true, the 87c5905afbSIngo Molnar nop will be converted to a jump instruction to execute the 88c5905afbSIngo Molnar conditional block of instructions. 89c5905afbSIngo Molnar 90c5905afbSIngo Molnar This technique lowers overhead and stress on the branch prediction 91c5905afbSIngo Molnar of the processor and generally makes the kernel faster. The update 92c5905afbSIngo Molnar of the condition is slower, but those are always very rare. 93c5905afbSIngo Molnar 94c5905afbSIngo Molnar ( On 32-bit x86, the necessary options added to the compiler 95c5905afbSIngo Molnar flags may increase the size of the kernel slightly. ) 9645f81b1cSSteven Rostedt 971987c947SPeter Zijlstraconfig STATIC_KEYS_SELFTEST 981987c947SPeter Zijlstra bool "Static key selftest" 991987c947SPeter Zijlstra depends on JUMP_LABEL 1001987c947SPeter Zijlstra help 1011987c947SPeter Zijlstra Boot time self-test of the branch patching code. 1021987c947SPeter Zijlstra 103afd66255SMasami Hiramatsuconfig OPTPROBES 1045cc718b9SMasami Hiramatsu def_bool y 1055cc718b9SMasami Hiramatsu depends on KPROBES && HAVE_OPTPROBES 106a30b85dfSMasami Hiramatsu select TASKS_RCU if PREEMPT 107afd66255SMasami Hiramatsu 108e7dbfe34SMasami Hiramatsuconfig KPROBES_ON_FTRACE 109e7dbfe34SMasami Hiramatsu def_bool y 110e7dbfe34SMasami Hiramatsu depends on KPROBES && HAVE_KPROBES_ON_FTRACE 111e7dbfe34SMasami Hiramatsu depends on DYNAMIC_FTRACE_WITH_REGS 112e7dbfe34SMasami Hiramatsu help 113e7dbfe34SMasami Hiramatsu If function tracer is enabled and the arch supports full 114e7dbfe34SMasami Hiramatsu passing of pt_regs to function tracing, then kprobes can 115e7dbfe34SMasami Hiramatsu optimize on top of function tracing. 116e7dbfe34SMasami Hiramatsu 1172b144498SSrikar Dronamrajuconfig UPROBES 11809294e31SDavid A. Long def_bool n 119e8f4aa60SAllen Pais depends on ARCH_SUPPORTS_UPROBES 1202b144498SSrikar Dronamraju help 1217b2d81d4SIngo Molnar Uprobes is the user-space counterpart to kprobes: they 1227b2d81d4SIngo Molnar enable instrumentation applications (such as 'perf probe') 1237b2d81d4SIngo Molnar to establish unintrusive probes in user-space binaries and 1247b2d81d4SIngo Molnar libraries, by executing handler functions when the probes 1257b2d81d4SIngo Molnar are hit by user-space applications. 1267b2d81d4SIngo Molnar 1277b2d81d4SIngo Molnar ( These probes come in the form of single-byte breakpoints, 1287b2d81d4SIngo Molnar managed by the kernel and kept transparent to the probed 1297b2d81d4SIngo Molnar application. ) 1302b144498SSrikar Dronamraju 13158340a07SJohannes Bergconfig HAVE_EFFICIENT_UNALIGNED_ACCESS 1329ba16087SJan Beulich bool 13358340a07SJohannes Berg help 13458340a07SJohannes Berg Some architectures are unable to perform unaligned accesses 13558340a07SJohannes Berg without the use of get_unaligned/put_unaligned. Others are 13658340a07SJohannes Berg unable to perform such accesses efficiently (e.g. trap on 13758340a07SJohannes Berg unaligned access and require fixing it up in the exception 13858340a07SJohannes Berg handler.) 13958340a07SJohannes Berg 14058340a07SJohannes Berg This symbol should be selected by an architecture if it can 14158340a07SJohannes Berg perform unaligned accesses efficiently to allow different 14258340a07SJohannes Berg code paths to be selected for these cases. Some network 14358340a07SJohannes Berg drivers, for example, could opt to not fix up alignment 14458340a07SJohannes Berg problems with received packets if doing so would not help 14558340a07SJohannes Berg much. 14658340a07SJohannes Berg 14758340a07SJohannes Berg See Documentation/unaligned-memory-access.txt for more 14858340a07SJohannes Berg information on the topic of unaligned memory accesses. 14958340a07SJohannes Berg 150cf66bb93SDavid Woodhouseconfig ARCH_USE_BUILTIN_BSWAP 151cf66bb93SDavid Woodhouse bool 152cf66bb93SDavid Woodhouse help 153cf66bb93SDavid Woodhouse Modern versions of GCC (since 4.4) have builtin functions 154cf66bb93SDavid Woodhouse for handling byte-swapping. Using these, instead of the old 155cf66bb93SDavid Woodhouse inline assembler that the architecture code provides in the 156cf66bb93SDavid Woodhouse __arch_bswapXX() macros, allows the compiler to see what's 157cf66bb93SDavid Woodhouse happening and offers more opportunity for optimisation. In 158cf66bb93SDavid Woodhouse particular, the compiler will be able to combine the byteswap 159cf66bb93SDavid Woodhouse with a nearby load or store and use load-and-swap or 160cf66bb93SDavid Woodhouse store-and-swap instructions if the architecture has them. It 161cf66bb93SDavid Woodhouse should almost *never* result in code which is worse than the 162cf66bb93SDavid Woodhouse hand-coded assembler in <asm/swab.h>. But just in case it 163cf66bb93SDavid Woodhouse does, the use of the builtins is optional. 164cf66bb93SDavid Woodhouse 165cf66bb93SDavid Woodhouse Any architecture with load-and-swap or store-and-swap 166cf66bb93SDavid Woodhouse instructions should set this. And it shouldn't hurt to set it 167cf66bb93SDavid Woodhouse on architectures that don't have such instructions. 168cf66bb93SDavid Woodhouse 1699edddaa2SAnanth N Mavinakayanahalliconfig KRETPROBES 1709edddaa2SAnanth N Mavinakayanahalli def_bool y 1719edddaa2SAnanth N Mavinakayanahalli depends on KPROBES && HAVE_KRETPROBES 1729edddaa2SAnanth N Mavinakayanahalli 1737c68af6eSAvi Kivityconfig USER_RETURN_NOTIFIER 1747c68af6eSAvi Kivity bool 1757c68af6eSAvi Kivity depends on HAVE_USER_RETURN_NOTIFIER 1767c68af6eSAvi Kivity help 1777c68af6eSAvi Kivity Provide a kernel-internal notification when a cpu is about to 1787c68af6eSAvi Kivity switch to user mode. 1797c68af6eSAvi Kivity 18028b2ee20SRik van Rielconfig HAVE_IOREMAP_PROT 1819ba16087SJan Beulich bool 18228b2ee20SRik van Riel 183125e5645SMathieu Desnoyersconfig HAVE_KPROBES 1849ba16087SJan Beulich bool 1859edddaa2SAnanth N Mavinakayanahalli 1869edddaa2SAnanth N Mavinakayanahalliconfig HAVE_KRETPROBES 1879ba16087SJan Beulich bool 18874bc7ceeSArthur Kepner 189afd66255SMasami Hiramatsuconfig HAVE_OPTPROBES 190afd66255SMasami Hiramatsu bool 191d314d74cSCong Wang 192e7dbfe34SMasami Hiramatsuconfig HAVE_KPROBES_ON_FTRACE 193e7dbfe34SMasami Hiramatsu bool 194e7dbfe34SMasami Hiramatsu 195540adea3SMasami Hiramatsuconfig HAVE_FUNCTION_ERROR_INJECTION 1969802d865SJosef Bacik bool 1979802d865SJosef Bacik 19842a0bb3fSPetr Mladekconfig HAVE_NMI 19942a0bb3fSPetr Mladek bool 20042a0bb3fSPetr Mladek 2011f5a4ad9SRoland McGrath# 2021f5a4ad9SRoland McGrath# An arch should select this if it provides all these things: 2031f5a4ad9SRoland McGrath# 2041f5a4ad9SRoland McGrath# task_pt_regs() in asm/processor.h or asm/ptrace.h 2051f5a4ad9SRoland McGrath# arch_has_single_step() if there is hardware single-step support 2061f5a4ad9SRoland McGrath# arch_has_block_step() if there is hardware block-step support 2071f5a4ad9SRoland McGrath# asm/syscall.h supplying asm-generic/syscall.h interface 2081f5a4ad9SRoland McGrath# linux/regset.h user_regset interfaces 2091f5a4ad9SRoland McGrath# CORE_DUMP_USE_REGSET #define'd in linux/elf.h 2101f5a4ad9SRoland McGrath# TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} 2111f5a4ad9SRoland McGrath# TIF_NOTIFY_RESUME calls tracehook_notify_resume() 2121f5a4ad9SRoland McGrath# signal delivery calls tracehook_signal_handler() 2131f5a4ad9SRoland McGrath# 2141f5a4ad9SRoland McGrathconfig HAVE_ARCH_TRACEHOOK 2159ba16087SJan Beulich bool 2161f5a4ad9SRoland McGrath 217c64be2bbSMarek Szyprowskiconfig HAVE_DMA_CONTIGUOUS 218c64be2bbSMarek Szyprowski bool 219c64be2bbSMarek Szyprowski 22029d5e047SThomas Gleixnerconfig GENERIC_SMP_IDLE_THREAD 22129d5e047SThomas Gleixner bool 22229d5e047SThomas Gleixner 223485cf5daSKevin Hilmanconfig GENERIC_IDLE_POLL_SETUP 224485cf5daSKevin Hilman bool 225485cf5daSKevin Hilman 2266974f0c4SDaniel Micayconfig ARCH_HAS_FORTIFY_SOURCE 2276974f0c4SDaniel Micay bool 2286974f0c4SDaniel Micay help 2296974f0c4SDaniel Micay An architecture should select this when it can successfully 2306974f0c4SDaniel Micay build and run with CONFIG_FORTIFY_SOURCE. 2316974f0c4SDaniel Micay 232d8ae8a37SChristoph Hellwig# 233d8ae8a37SChristoph Hellwig# Select if the arch provides a historic keepinit alias for the retain_initrd 234d8ae8a37SChristoph Hellwig# command line option 235d8ae8a37SChristoph Hellwig# 236d8ae8a37SChristoph Hellwigconfig ARCH_HAS_KEEPINITRD 237d8ae8a37SChristoph Hellwig bool 238d8ae8a37SChristoph Hellwig 239d2852a22SDaniel Borkmann# Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h 240d2852a22SDaniel Borkmannconfig ARCH_HAS_SET_MEMORY 241d2852a22SDaniel Borkmann bool 242d2852a22SDaniel Borkmann 243d253ca0cSRick Edgecombe# Select if arch has all set_direct_map_invalid/default() functions 244d253ca0cSRick Edgecombeconfig ARCH_HAS_SET_DIRECT_MAP 245d253ca0cSRick Edgecombe bool 246d253ca0cSRick Edgecombe 247c30700dbSChristoph Hellwig# 248c30700dbSChristoph Hellwig# Select if arch has an uncached kernel segment and provides the 249c30700dbSChristoph Hellwig# uncached_kernel_address / cached_kernel_address symbols to use it 250c30700dbSChristoph Hellwig# 251c30700dbSChristoph Hellwigconfig ARCH_HAS_UNCACHED_SEGMENT 252c30700dbSChristoph Hellwig select ARCH_HAS_DMA_PREP_COHERENT 253c30700dbSChristoph Hellwig bool 254c30700dbSChristoph Hellwig 2550500871fSDavid Howells# Select if arch init_task must go in the __init_task_data section 2560500871fSDavid Howellsconfig ARCH_TASK_STRUCT_ON_STACK 257a4a2eb49SThomas Gleixner bool 258a4a2eb49SThomas Gleixner 259f5e10287SThomas Gleixner# Select if arch has its private alloc_task_struct() function 260f5e10287SThomas Gleixnerconfig ARCH_TASK_STRUCT_ALLOCATOR 261f5e10287SThomas Gleixner bool 262f5e10287SThomas Gleixner 2635905429aSKees Cookconfig HAVE_ARCH_THREAD_STRUCT_WHITELIST 2645905429aSKees Cook bool 2655905429aSKees Cook depends on !ARCH_TASK_STRUCT_ALLOCATOR 2665905429aSKees Cook help 2675905429aSKees Cook An architecture should select this to provide hardened usercopy 2685905429aSKees Cook knowledge about what region of the thread_struct should be 2695905429aSKees Cook whitelisted for copying to userspace. Normally this is only the 2705905429aSKees Cook FPU registers. Specifically, arch_thread_struct_whitelist() 2715905429aSKees Cook should be implemented. Without this, the entire thread_struct 2725905429aSKees Cook field in task_struct will be left whitelisted. 2735905429aSKees Cook 274b235beeaSLinus Torvalds# Select if arch has its private alloc_thread_stack() function 275b235beeaSLinus Torvaldsconfig ARCH_THREAD_STACK_ALLOCATOR 276f5e10287SThomas Gleixner bool 277f5e10287SThomas Gleixner 2785aaeb5c0SIngo Molnar# Select if arch wants to size task_struct dynamically via arch_task_struct_size: 2795aaeb5c0SIngo Molnarconfig ARCH_WANTS_DYNAMIC_TASK_STRUCT 2805aaeb5c0SIngo Molnar bool 2815aaeb5c0SIngo Molnar 282942fa985SYury Norovconfig ARCH_32BIT_OFF_T 283942fa985SYury Norov bool 284942fa985SYury Norov depends on !64BIT 285942fa985SYury Norov help 286942fa985SYury Norov All new 32-bit architectures should have 64-bit off_t type on 287942fa985SYury Norov userspace side which corresponds to the loff_t kernel type. This 288942fa985SYury Norov is the requirement for modern ABIs. Some existing architectures 289942fa985SYury Norov still support 32-bit off_t. This option is enabled for all such 290942fa985SYury Norov architectures explicitly. 291942fa985SYury Norov 2922ff2b7ecSMasahiro Yamadaconfig HAVE_ASM_MODVERSIONS 2932ff2b7ecSMasahiro Yamada bool 2942ff2b7ecSMasahiro Yamada help 2952ff2b7ecSMasahiro Yamada This symbol should be selected by an architecure if it provides 2962ff2b7ecSMasahiro Yamada <asm/asm-prototypes.h> to support the module versioning for symbols 2972ff2b7ecSMasahiro Yamada exported from assembly code. 2982ff2b7ecSMasahiro Yamada 299f850c30cSHeiko Carstensconfig HAVE_REGS_AND_STACK_ACCESS_API 300f850c30cSHeiko Carstens bool 301e01292b1SHeiko Carstens help 302e01292b1SHeiko Carstens This symbol should be selected by an architecure if it supports 303e01292b1SHeiko Carstens the API needed to access registers and stack entries from pt_regs, 304e01292b1SHeiko Carstens declared in asm/ptrace.h 305e01292b1SHeiko Carstens For example the kprobes-based event tracer needs this API. 306f850c30cSHeiko Carstens 307d7822b1eSMathieu Desnoyersconfig HAVE_RSEQ 308d7822b1eSMathieu Desnoyers bool 309d7822b1eSMathieu Desnoyers depends on HAVE_REGS_AND_STACK_ACCESS_API 310d7822b1eSMathieu Desnoyers help 311d7822b1eSMathieu Desnoyers This symbol should be selected by an architecture if it 312d7822b1eSMathieu Desnoyers supports an implementation of restartable sequences. 313d7822b1eSMathieu Desnoyers 3143c88ee19SMasami Hiramatsuconfig HAVE_FUNCTION_ARG_ACCESS_API 3153c88ee19SMasami Hiramatsu bool 3163c88ee19SMasami Hiramatsu help 3173c88ee19SMasami Hiramatsu This symbol should be selected by an architecure if it supports 3183c88ee19SMasami Hiramatsu the API needed to access function arguments from pt_regs, 3193c88ee19SMasami Hiramatsu declared in asm/ptrace.h 3203c88ee19SMasami Hiramatsu 3219483a578SDavid Brownellconfig HAVE_CLK 3229ba16087SJan Beulich bool 3239483a578SDavid Brownell help 3249483a578SDavid Brownell The <linux/clk.h> calls support software clock gating and 3259483a578SDavid Brownell thus are a key power management tool on many systems. 3269483a578SDavid Brownell 32762a038d3SK.Prasadconfig HAVE_HW_BREAKPOINT 32862a038d3SK.Prasad bool 32999e8c5a3SFrederic Weisbecker depends on PERF_EVENTS 33062a038d3SK.Prasad 3310102752eSFrederic Weisbeckerconfig HAVE_MIXED_BREAKPOINTS_REGS 3320102752eSFrederic Weisbecker bool 3330102752eSFrederic Weisbecker depends on HAVE_HW_BREAKPOINT 3340102752eSFrederic Weisbecker help 3350102752eSFrederic Weisbecker Depending on the arch implementation of hardware breakpoints, 3360102752eSFrederic Weisbecker some of them have separate registers for data and instruction 3370102752eSFrederic Weisbecker breakpoints addresses, others have mixed registers to store 3380102752eSFrederic Weisbecker them but define the access type in a control register. 3390102752eSFrederic Weisbecker Select this option if your arch implements breakpoints under the 3400102752eSFrederic Weisbecker latter fashion. 3410102752eSFrederic Weisbecker 3427c68af6eSAvi Kivityconfig HAVE_USER_RETURN_NOTIFIER 3437c68af6eSAvi Kivity bool 344a1922ed6SIngo Molnar 345c01d4323SFrederic Weisbeckerconfig HAVE_PERF_EVENTS_NMI 346c01d4323SFrederic Weisbecker bool 34723637d47SFrederic Weisbecker help 34823637d47SFrederic Weisbecker System hardware can generate an NMI using the perf event 34923637d47SFrederic Weisbecker subsystem. Also has support for calculating CPU cycle events 35023637d47SFrederic Weisbecker to determine how many clock cycles in a given period. 351c01d4323SFrederic Weisbecker 35205a4a952SNicholas Pigginconfig HAVE_HARDLOCKUP_DETECTOR_PERF 35305a4a952SNicholas Piggin bool 35405a4a952SNicholas Piggin depends on HAVE_PERF_EVENTS_NMI 35505a4a952SNicholas Piggin help 35605a4a952SNicholas Piggin The arch chooses to use the generic perf-NMI-based hardlockup 35705a4a952SNicholas Piggin detector. Must define HAVE_PERF_EVENTS_NMI. 35805a4a952SNicholas Piggin 35905a4a952SNicholas Pigginconfig HAVE_NMI_WATCHDOG 36005a4a952SNicholas Piggin depends on HAVE_NMI 36105a4a952SNicholas Piggin bool 36205a4a952SNicholas Piggin help 36305a4a952SNicholas Piggin The arch provides a low level NMI watchdog. It provides 36405a4a952SNicholas Piggin asm/nmi.h, and defines its own arch_touch_nmi_watchdog(). 36505a4a952SNicholas Piggin 36605a4a952SNicholas Pigginconfig HAVE_HARDLOCKUP_DETECTOR_ARCH 36705a4a952SNicholas Piggin bool 36805a4a952SNicholas Piggin select HAVE_NMI_WATCHDOG 36905a4a952SNicholas Piggin help 37005a4a952SNicholas Piggin The arch chooses to provide its own hardlockup detector, which is 37105a4a952SNicholas Piggin a superset of the HAVE_NMI_WATCHDOG. It also conforms to config 37205a4a952SNicholas Piggin interfaces and parameters provided by hardlockup detector subsystem. 37305a4a952SNicholas Piggin 374c5e63197SJiri Olsaconfig HAVE_PERF_REGS 375c5e63197SJiri Olsa bool 376c5e63197SJiri Olsa help 377c5e63197SJiri Olsa Support selective register dumps for perf events. This includes 378c5e63197SJiri Olsa bit-mapping of each registers and a unique architecture id. 379c5e63197SJiri Olsa 380c5ebcedbSJiri Olsaconfig HAVE_PERF_USER_STACK_DUMP 381c5ebcedbSJiri Olsa bool 382c5ebcedbSJiri Olsa help 383c5ebcedbSJiri Olsa Support user stack dumps for perf event samples. This needs 384c5ebcedbSJiri Olsa access to the user stack pointer which is not unified across 385c5ebcedbSJiri Olsa architectures. 386c5ebcedbSJiri Olsa 387bf5438fcSJason Baronconfig HAVE_ARCH_JUMP_LABEL 388bf5438fcSJason Baron bool 389bf5438fcSJason Baron 39050ff18abSArd Biesheuvelconfig HAVE_ARCH_JUMP_LABEL_RELATIVE 39150ff18abSArd Biesheuvel bool 39250ff18abSArd Biesheuvel 39326723911SPeter Zijlstraconfig HAVE_RCU_TABLE_FREE 39426723911SPeter Zijlstra bool 39526723911SPeter Zijlstra 39696bc9567SPeter Zijlstraconfig HAVE_RCU_TABLE_NO_INVALIDATE 397d86564a2SPeter Zijlstra bool 398d86564a2SPeter Zijlstra 399ed6a7935SPeter Zijlstraconfig HAVE_MMU_GATHER_PAGE_SIZE 400ed6a7935SPeter Zijlstra bool 401ed6a7935SPeter Zijlstra 402952a31c9SMartin Schwidefskyconfig HAVE_MMU_GATHER_NO_GATHER 403952a31c9SMartin Schwidefsky bool 404952a31c9SMartin Schwidefsky 405df013ffbSHuang Yingconfig ARCH_HAVE_NMI_SAFE_CMPXCHG 406df013ffbSHuang Ying bool 407df013ffbSHuang Ying 40843570fd2SHeiko Carstensconfig HAVE_ALIGNED_STRUCT_PAGE 40943570fd2SHeiko Carstens bool 41043570fd2SHeiko Carstens help 41143570fd2SHeiko Carstens This makes sure that struct pages are double word aligned and that 41243570fd2SHeiko Carstens e.g. the SLUB allocator can perform double word atomic operations 41343570fd2SHeiko Carstens on a struct page for better performance. However selecting this 41443570fd2SHeiko Carstens might increase the size of a struct page by a word. 41543570fd2SHeiko Carstens 4164156153cSHeiko Carstensconfig HAVE_CMPXCHG_LOCAL 4174156153cSHeiko Carstens bool 4184156153cSHeiko Carstens 4192565409fSHeiko Carstensconfig HAVE_CMPXCHG_DOUBLE 4202565409fSHeiko Carstens bool 4212565409fSHeiko Carstens 42277e58496SPaul E. McKenneyconfig ARCH_WEAK_RELEASE_ACQUIRE 42377e58496SPaul E. McKenney bool 42477e58496SPaul E. McKenney 425c1d7e01dSWill Deaconconfig ARCH_WANT_IPC_PARSE_VERSION 426c1d7e01dSWill Deacon bool 427c1d7e01dSWill Deacon 428c1d7e01dSWill Deaconconfig ARCH_WANT_COMPAT_IPC_PARSE_VERSION 429c1d7e01dSWill Deacon bool 430c1d7e01dSWill Deacon 43148b25c43SChris Metcalfconfig ARCH_WANT_OLD_COMPAT_IPC 432c1d7e01dSWill Deacon select ARCH_WANT_COMPAT_IPC_PARSE_VERSION 43348b25c43SChris Metcalf bool 43448b25c43SChris Metcalf 435e2cfabdfSWill Drewryconfig HAVE_ARCH_SECCOMP_FILTER 436e2cfabdfSWill Drewry bool 437e2cfabdfSWill Drewry help 438fb0fadf9SWill Drewry An arch should select this symbol if it provides all of these things: 439bb6ea430SWill Drewry - syscall_get_arch() 440bb6ea430SWill Drewry - syscall_get_arguments() 441bb6ea430SWill Drewry - syscall_rollback() 442bb6ea430SWill Drewry - syscall_set_return_value() 443fb0fadf9SWill Drewry - SIGSYS siginfo_t support 444fb0fadf9SWill Drewry - secure_computing is called from a ptrace_event()-safe context 445fb0fadf9SWill Drewry - secure_computing return value is checked and a return value of -1 446fb0fadf9SWill Drewry results in the system call being skipped immediately. 44748dc92b9SKees Cook - seccomp syscall wired up 448e2cfabdfSWill Drewry 449e2cfabdfSWill Drewryconfig SECCOMP_FILTER 450e2cfabdfSWill Drewry def_bool y 451e2cfabdfSWill Drewry depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET 452e2cfabdfSWill Drewry help 453e2cfabdfSWill Drewry Enable tasks to build secure computing environments defined 454e2cfabdfSWill Drewry in terms of Berkeley Packet Filter programs which implement 455e2cfabdfSWill Drewry task-defined system call filtering polices. 456e2cfabdfSWill Drewry 4575fb94e9cSMauro Carvalho Chehab See Documentation/userspace-api/seccomp_filter.rst for details. 458e2cfabdfSWill Drewry 459afaef01cSAlexander Popovconfig HAVE_ARCH_STACKLEAK 460afaef01cSAlexander Popov bool 461afaef01cSAlexander Popov help 462afaef01cSAlexander Popov An architecture should select this if it has the code which 463afaef01cSAlexander Popov fills the used part of the kernel stack with the STACKLEAK_POISON 464afaef01cSAlexander Popov value before returning from system calls. 465afaef01cSAlexander Popov 466d148eac0SMasahiro Yamadaconfig HAVE_STACKPROTECTOR 46719952a92SKees Cook bool 46819952a92SKees Cook help 46919952a92SKees Cook An arch should select this symbol if: 47019952a92SKees Cook - it has implemented a stack canary (e.g. __stack_chk_guard) 47119952a92SKees Cook 4722a61f474SMasahiro Yamadaconfig CC_HAS_STACKPROTECTOR_NONE 4732a61f474SMasahiro Yamada def_bool $(cc-option,-fno-stack-protector) 4742a61f474SMasahiro Yamada 475050e9baaSLinus Torvaldsconfig STACKPROTECTOR 4762a61f474SMasahiro Yamada bool "Stack Protector buffer overflow detection" 477d148eac0SMasahiro Yamada depends on HAVE_STACKPROTECTOR 4782a61f474SMasahiro Yamada depends on $(cc-option,-fstack-protector) 4792a61f474SMasahiro Yamada default y 4808779657dSKees Cook help 4818779657dSKees Cook This option turns on the "stack-protector" GCC feature. This 48219952a92SKees Cook feature puts, at the beginning of functions, a canary value on 48319952a92SKees Cook the stack just before the return address, and validates 48419952a92SKees Cook the value just before actually returning. Stack based buffer 48519952a92SKees Cook overflows (that need to overwrite this return address) now also 48619952a92SKees Cook overwrite the canary, which gets detected and the attack is then 48719952a92SKees Cook neutralized via a kernel panic. 48819952a92SKees Cook 4898779657dSKees Cook Functions will have the stack-protector canary logic added if they 4908779657dSKees Cook have an 8-byte or larger character array on the stack. 4918779657dSKees Cook 49219952a92SKees Cook This feature requires gcc version 4.2 or above, or a distribution 4938779657dSKees Cook gcc with the feature backported ("-fstack-protector"). 4948779657dSKees Cook 4958779657dSKees Cook On an x86 "defconfig" build, this feature adds canary checks to 4968779657dSKees Cook about 3% of all kernel functions, which increases kernel code size 4978779657dSKees Cook by about 0.3%. 4988779657dSKees Cook 499050e9baaSLinus Torvaldsconfig STACKPROTECTOR_STRONG 5002a61f474SMasahiro Yamada bool "Strong Stack Protector" 501050e9baaSLinus Torvalds depends on STACKPROTECTOR 5022a61f474SMasahiro Yamada depends on $(cc-option,-fstack-protector-strong) 5032a61f474SMasahiro Yamada default y 5048779657dSKees Cook help 5058779657dSKees Cook Functions will have the stack-protector canary logic added in any 5068779657dSKees Cook of the following conditions: 5078779657dSKees Cook 5088779657dSKees Cook - local variable's address used as part of the right hand side of an 5098779657dSKees Cook assignment or function argument 5108779657dSKees Cook - local variable is an array (or union containing an array), 5118779657dSKees Cook regardless of array type or length 5128779657dSKees Cook - uses register local variables 5138779657dSKees Cook 5148779657dSKees Cook This feature requires gcc version 4.9 or above, or a distribution 5158779657dSKees Cook gcc with the feature backported ("-fstack-protector-strong"). 5168779657dSKees Cook 5178779657dSKees Cook On an x86 "defconfig" build, this feature adds canary checks to 5188779657dSKees Cook about 20% of all kernel functions, which increases the kernel code 5198779657dSKees Cook size by about 2%. 5208779657dSKees Cook 5210f60a8efSKees Cookconfig HAVE_ARCH_WITHIN_STACK_FRAMES 5220f60a8efSKees Cook bool 5230f60a8efSKees Cook help 5240f60a8efSKees Cook An architecture should select this if it can walk the kernel stack 5250f60a8efSKees Cook frames to determine if an object is part of either the arguments 5260f60a8efSKees Cook or local variables (i.e. that it excludes saved return addresses, 5270f60a8efSKees Cook and similar) by implementing an inline arch_within_stack_frames(), 5280f60a8efSKees Cook which is used by CONFIG_HARDENED_USERCOPY. 5290f60a8efSKees Cook 53091d1aa43SFrederic Weisbeckerconfig HAVE_CONTEXT_TRACKING 5312b1d5024SFrederic Weisbecker bool 5322b1d5024SFrederic Weisbecker help 53391d1aa43SFrederic Weisbecker Provide kernel/user boundaries probes necessary for subsystems 53491d1aa43SFrederic Weisbecker that need it, such as userspace RCU extended quiescent state. 53591d1aa43SFrederic Weisbecker Syscalls need to be wrapped inside user_exit()-user_enter() through 53691d1aa43SFrederic Weisbecker the slow path using TIF_NOHZ flag. Exceptions handlers must be 53791d1aa43SFrederic Weisbecker wrapped as well. Irqs are already protected inside 53891d1aa43SFrederic Weisbecker rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on 53991d1aa43SFrederic Weisbecker irq exit still need to be protected. 5402b1d5024SFrederic Weisbecker 541b952741cSFrederic Weisbeckerconfig HAVE_VIRT_CPU_ACCOUNTING 542b952741cSFrederic Weisbecker bool 543b952741cSFrederic Weisbecker 54440565b5aSStanislaw Gruszkaconfig ARCH_HAS_SCALED_CPUTIME 54540565b5aSStanislaw Gruszka bool 54640565b5aSStanislaw Gruszka 547554b0004SKevin Hilmanconfig HAVE_VIRT_CPU_ACCOUNTING_GEN 548554b0004SKevin Hilman bool 549554b0004SKevin Hilman default y if 64BIT 550554b0004SKevin Hilman help 551554b0004SKevin Hilman With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. 552554b0004SKevin Hilman Before enabling this option, arch code must be audited 553554b0004SKevin Hilman to ensure there are no races in concurrent read/write of 554554b0004SKevin Hilman cputime_t. For example, reading/writing 64-bit cputime_t on 555554b0004SKevin Hilman some 32-bit arches may require multiple accesses, so proper 556554b0004SKevin Hilman locking is needed to protect against concurrent accesses. 557554b0004SKevin Hilman 558554b0004SKevin Hilman 559fdf9c356SFrederic Weisbeckerconfig HAVE_IRQ_TIME_ACCOUNTING 560fdf9c356SFrederic Weisbecker bool 561fdf9c356SFrederic Weisbecker help 562fdf9c356SFrederic Weisbecker Archs need to ensure they use a high enough resolution clock to 563fdf9c356SFrederic Weisbecker support irq time accounting and then call enable_sched_clock_irqtime(). 564fdf9c356SFrederic Weisbecker 5652c91bd4aSJoel Fernandes (Google)config HAVE_MOVE_PMD 5662c91bd4aSJoel Fernandes (Google) bool 5672c91bd4aSJoel Fernandes (Google) help 5682c91bd4aSJoel Fernandes (Google) Archs that select this are able to move page tables at the PMD level. 5692c91bd4aSJoel Fernandes (Google) 57015626062SGerald Schaeferconfig HAVE_ARCH_TRANSPARENT_HUGEPAGE 57115626062SGerald Schaefer bool 57215626062SGerald Schaefer 573a00cc7d9SMatthew Wilcoxconfig HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 574a00cc7d9SMatthew Wilcox bool 575a00cc7d9SMatthew Wilcox 5760ddab1d2SToshi Kaniconfig HAVE_ARCH_HUGE_VMAP 5770ddab1d2SToshi Kani bool 5780ddab1d2SToshi Kani 5793876d4a3SAlexandre Ghiticonfig ARCH_WANT_HUGE_PMD_SHARE 5803876d4a3SAlexandre Ghiti bool 5813876d4a3SAlexandre Ghiti 5820f8975ecSPavel Emelyanovconfig HAVE_ARCH_SOFT_DIRTY 5830f8975ecSPavel Emelyanov bool 5840f8975ecSPavel Emelyanov 585786d35d4SDavid Howellsconfig HAVE_MOD_ARCH_SPECIFIC 586786d35d4SDavid Howells bool 587786d35d4SDavid Howells help 588786d35d4SDavid Howells The arch uses struct mod_arch_specific to store data. Many arches 589786d35d4SDavid Howells just need a simple module loader without arch specific data - those 590786d35d4SDavid Howells should not enable this. 591786d35d4SDavid Howells 592786d35d4SDavid Howellsconfig MODULES_USE_ELF_RELA 593786d35d4SDavid Howells bool 594786d35d4SDavid Howells help 595786d35d4SDavid Howells Modules only use ELF RELA relocations. Modules with ELF REL 596786d35d4SDavid Howells relocations will give an error. 597786d35d4SDavid Howells 598786d35d4SDavid Howellsconfig MODULES_USE_ELF_REL 599786d35d4SDavid Howells bool 600786d35d4SDavid Howells help 601786d35d4SDavid Howells Modules only use ELF REL relocations. Modules with ELF RELA 602786d35d4SDavid Howells relocations will give an error. 603786d35d4SDavid Howells 604cc1f0274SFrederic Weisbeckerconfig HAVE_IRQ_EXIT_ON_IRQ_STACK 605cc1f0274SFrederic Weisbecker bool 606cc1f0274SFrederic Weisbecker help 607cc1f0274SFrederic Weisbecker Architecture doesn't only execute the irq handler on the irq stack 608cc1f0274SFrederic Weisbecker but also irq_exit(). This way we can process softirqs on this irq 609cc1f0274SFrederic Weisbecker stack instead of switching to a new one when we call __do_softirq() 610cc1f0274SFrederic Weisbecker in the end of an hardirq. 611cc1f0274SFrederic Weisbecker This spares a stack switch and improves cache usage on softirq 612cc1f0274SFrederic Weisbecker processing. 613cc1f0274SFrederic Weisbecker 614235a8f02SKirill A. Shutemovconfig PGTABLE_LEVELS 615235a8f02SKirill A. Shutemov int 616235a8f02SKirill A. Shutemov default 2 617235a8f02SKirill A. Shutemov 6182b68f6caSKees Cookconfig ARCH_HAS_ELF_RANDOMIZE 6192b68f6caSKees Cook bool 6202b68f6caSKees Cook help 6212b68f6caSKees Cook An architecture supports choosing randomized locations for 6222b68f6caSKees Cook stack, mmap, brk, and ET_DYN. Defined functions: 6232b68f6caSKees Cook - arch_mmap_rnd() 624204db6edSKees Cook - arch_randomize_brk() 6252b68f6caSKees Cook 626d07e2259SDaniel Cashmanconfig HAVE_ARCH_MMAP_RND_BITS 627d07e2259SDaniel Cashman bool 628d07e2259SDaniel Cashman help 629d07e2259SDaniel Cashman An arch should select this symbol if it supports setting a variable 630d07e2259SDaniel Cashman number of bits for use in establishing the base address for mmap 631d07e2259SDaniel Cashman allocations, has MMU enabled and provides values for both: 632d07e2259SDaniel Cashman - ARCH_MMAP_RND_BITS_MIN 633d07e2259SDaniel Cashman - ARCH_MMAP_RND_BITS_MAX 634d07e2259SDaniel Cashman 6355f56a5dfSJiri Slabyconfig HAVE_EXIT_THREAD 6365f56a5dfSJiri Slaby bool 6375f56a5dfSJiri Slaby help 6385f56a5dfSJiri Slaby An architecture implements exit_thread. 6395f56a5dfSJiri Slaby 640d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 641d07e2259SDaniel Cashman int 642d07e2259SDaniel Cashman 643d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 644d07e2259SDaniel Cashman int 645d07e2259SDaniel Cashman 646d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS_DEFAULT 647d07e2259SDaniel Cashman int 648d07e2259SDaniel Cashman 649d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS 650d07e2259SDaniel Cashman int "Number of bits to use for ASLR of mmap base address" if EXPERT 651d07e2259SDaniel Cashman range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX 652d07e2259SDaniel Cashman default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT 653d07e2259SDaniel Cashman default ARCH_MMAP_RND_BITS_MIN 654d07e2259SDaniel Cashman depends on HAVE_ARCH_MMAP_RND_BITS 655d07e2259SDaniel Cashman help 656d07e2259SDaniel Cashman This value can be used to select the number of bits to use to 657d07e2259SDaniel Cashman determine the random offset to the base address of vma regions 658d07e2259SDaniel Cashman resulting from mmap allocations. This value will be bounded 659d07e2259SDaniel Cashman by the architecture's minimum and maximum supported values. 660d07e2259SDaniel Cashman 661d07e2259SDaniel Cashman This value can be changed after boot using the 662d07e2259SDaniel Cashman /proc/sys/vm/mmap_rnd_bits tunable 663d07e2259SDaniel Cashman 664d07e2259SDaniel Cashmanconfig HAVE_ARCH_MMAP_RND_COMPAT_BITS 665d07e2259SDaniel Cashman bool 666d07e2259SDaniel Cashman help 667d07e2259SDaniel Cashman An arch should select this symbol if it supports running applications 668d07e2259SDaniel Cashman in compatibility mode, supports setting a variable number of bits for 669d07e2259SDaniel Cashman use in establishing the base address for mmap allocations, has MMU 670d07e2259SDaniel Cashman enabled and provides values for both: 671d07e2259SDaniel Cashman - ARCH_MMAP_RND_COMPAT_BITS_MIN 672d07e2259SDaniel Cashman - ARCH_MMAP_RND_COMPAT_BITS_MAX 673d07e2259SDaniel Cashman 674d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 675d07e2259SDaniel Cashman int 676d07e2259SDaniel Cashman 677d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 678d07e2259SDaniel Cashman int 679d07e2259SDaniel Cashman 680d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 681d07e2259SDaniel Cashman int 682d07e2259SDaniel Cashman 683d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS 684d07e2259SDaniel Cashman int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT 685d07e2259SDaniel Cashman range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX 686d07e2259SDaniel Cashman default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 687d07e2259SDaniel Cashman default ARCH_MMAP_RND_COMPAT_BITS_MIN 688d07e2259SDaniel Cashman depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS 689d07e2259SDaniel Cashman help 690d07e2259SDaniel Cashman This value can be used to select the number of bits to use to 691d07e2259SDaniel Cashman determine the random offset to the base address of vma regions 692d07e2259SDaniel Cashman resulting from mmap allocations for compatible applications This 693d07e2259SDaniel Cashman value will be bounded by the architecture's minimum and maximum 694d07e2259SDaniel Cashman supported values. 695d07e2259SDaniel Cashman 696d07e2259SDaniel Cashman This value can be changed after boot using the 697d07e2259SDaniel Cashman /proc/sys/vm/mmap_rnd_compat_bits tunable 698d07e2259SDaniel Cashman 6991b028f78SDmitry Safonovconfig HAVE_ARCH_COMPAT_MMAP_BASES 7001b028f78SDmitry Safonov bool 7011b028f78SDmitry Safonov help 7021b028f78SDmitry Safonov This allows 64bit applications to invoke 32-bit mmap() syscall 7031b028f78SDmitry Safonov and vice-versa 32-bit applications to call 64-bit mmap(). 7041b028f78SDmitry Safonov Required for applications doing different bitness syscalls. 7051b028f78SDmitry Safonov 7063033f14aSJosh Triplettconfig HAVE_COPY_THREAD_TLS 7073033f14aSJosh Triplett bool 7083033f14aSJosh Triplett help 7093033f14aSJosh Triplett Architecture provides copy_thread_tls to accept tls argument via 7103033f14aSJosh Triplett normal C parameter passing, rather than extracting the syscall 7113033f14aSJosh Triplett argument from pt_regs. 7123033f14aSJosh Triplett 713b9ab5ebbSJosh Poimboeufconfig HAVE_STACK_VALIDATION 714b9ab5ebbSJosh Poimboeuf bool 715b9ab5ebbSJosh Poimboeuf help 716b9ab5ebbSJosh Poimboeuf Architecture supports the 'objtool check' host tool command, which 717b9ab5ebbSJosh Poimboeuf performs compile-time stack metadata validation. 718b9ab5ebbSJosh Poimboeuf 719af085d90SJosh Poimboeufconfig HAVE_RELIABLE_STACKTRACE 720af085d90SJosh Poimboeuf bool 721af085d90SJosh Poimboeuf help 722af085d90SJosh Poimboeuf Architecture has a save_stack_trace_tsk_reliable() function which 723af085d90SJosh Poimboeuf only returns a stack trace if it can guarantee the trace is reliable. 724af085d90SJosh Poimboeuf 725468a9428SGeorge Spelvinconfig HAVE_ARCH_HASH 726468a9428SGeorge Spelvin bool 727468a9428SGeorge Spelvin default n 728468a9428SGeorge Spelvin help 729468a9428SGeorge Spelvin If this is set, the architecture provides an <asm/hash.h> 730468a9428SGeorge Spelvin file which provides platform-specific implementations of some 731468a9428SGeorge Spelvin functions in <linux/hash.h> or fs/namei.c. 732468a9428SGeorge Spelvin 733666047feSFinn Thainconfig HAVE_ARCH_NVRAM_OPS 734666047feSFinn Thain bool 735666047feSFinn Thain 7363a495511SWilliam Breathitt Grayconfig ISA_BUS_API 7373a495511SWilliam Breathitt Gray def_bool ISA 7383a495511SWilliam Breathitt Gray 739d2125043SAl Viro# 740d2125043SAl Viro# ABI hall of shame 741d2125043SAl Viro# 742d2125043SAl Viroconfig CLONE_BACKWARDS 743d2125043SAl Viro bool 744d2125043SAl Viro help 745d2125043SAl Viro Architecture has tls passed as the 4th argument of clone(2), 746d2125043SAl Viro not the 5th one. 747d2125043SAl Viro 748d2125043SAl Viroconfig CLONE_BACKWARDS2 749d2125043SAl Viro bool 750d2125043SAl Viro help 751d2125043SAl Viro Architecture has the first two arguments of clone(2) swapped. 752d2125043SAl Viro 753dfa9771aSMichal Simekconfig CLONE_BACKWARDS3 754dfa9771aSMichal Simek bool 755dfa9771aSMichal Simek help 756dfa9771aSMichal Simek Architecture has tls passed as the 3rd argument of clone(2), 757dfa9771aSMichal Simek not the 5th one. 758dfa9771aSMichal Simek 759eaca6eaeSAl Viroconfig ODD_RT_SIGACTION 760eaca6eaeSAl Viro bool 761eaca6eaeSAl Viro help 762eaca6eaeSAl Viro Architecture has unusual rt_sigaction(2) arguments 763eaca6eaeSAl Viro 7640a0e8cdfSAl Viroconfig OLD_SIGSUSPEND 7650a0e8cdfSAl Viro bool 7660a0e8cdfSAl Viro help 7670a0e8cdfSAl Viro Architecture has old sigsuspend(2) syscall, of one-argument variety 7680a0e8cdfSAl Viro 7690a0e8cdfSAl Viroconfig OLD_SIGSUSPEND3 7700a0e8cdfSAl Viro bool 7710a0e8cdfSAl Viro help 7720a0e8cdfSAl Viro Even weirder antique ABI - three-argument sigsuspend(2) 7730a0e8cdfSAl Viro 774495dfbf7SAl Viroconfig OLD_SIGACTION 775495dfbf7SAl Viro bool 776495dfbf7SAl Viro help 777495dfbf7SAl Viro Architecture has old sigaction(2) syscall. Nope, not the same 778495dfbf7SAl Viro as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), 779495dfbf7SAl Viro but fairly different variant of sigaction(2), thanks to OSF/1 780495dfbf7SAl Viro compatibility... 781495dfbf7SAl Viro 782495dfbf7SAl Viroconfig COMPAT_OLD_SIGACTION 783495dfbf7SAl Viro bool 784495dfbf7SAl Viro 785d4703ddaSDeepa Dinamaniconfig 64BIT_TIME 786f3d96467SArnd Bergmann def_bool y 787d4703ddaSDeepa Dinamani help 788d4703ddaSDeepa Dinamani This should be selected by all architectures that need to support 789d4703ddaSDeepa Dinamani new system calls with a 64-bit time_t. This is relevant on all 32-bit 790d4703ddaSDeepa Dinamani architectures, and 64-bit architectures as part of compat syscall 791d4703ddaSDeepa Dinamani handling. 792d4703ddaSDeepa Dinamani 79317435e5fSDeepa Dinamaniconfig COMPAT_32BIT_TIME 79400bf25d6SArnd Bergmann def_bool !64BIT || COMPAT 79517435e5fSDeepa Dinamani help 79617435e5fSDeepa Dinamani This enables 32 bit time_t support in addition to 64 bit time_t support. 79717435e5fSDeepa Dinamani This is relevant on all 32-bit architectures, and 64-bit architectures 79817435e5fSDeepa Dinamani as part of compat syscall handling. 79917435e5fSDeepa Dinamani 8000d4a619bSChristoph Hellwigconfig ARCH_NO_COHERENT_DMA_MMAP 8010d4a619bSChristoph Hellwig bool 8020d4a619bSChristoph Hellwig 80387a4c375SChristoph Hellwigconfig ARCH_NO_PREEMPT 80487a4c375SChristoph Hellwig bool 80587a4c375SChristoph Hellwig 806a50a3f4bSThomas Gleixnerconfig ARCH_SUPPORTS_RT 807a50a3f4bSThomas Gleixner bool 808a50a3f4bSThomas Gleixner 809fff7fb0bSZhaoxiu Zengconfig CPU_NO_EFFICIENT_FFS 810fff7fb0bSZhaoxiu Zeng def_bool n 811fff7fb0bSZhaoxiu Zeng 812ba14a194SAndy Lutomirskiconfig HAVE_ARCH_VMAP_STACK 813ba14a194SAndy Lutomirski def_bool n 814ba14a194SAndy Lutomirski help 815ba14a194SAndy Lutomirski An arch should select this symbol if it can support kernel stacks 816ba14a194SAndy Lutomirski in vmalloc space. This means: 817ba14a194SAndy Lutomirski 818ba14a194SAndy Lutomirski - vmalloc space must be large enough to hold many kernel stacks. 819ba14a194SAndy Lutomirski This may rule out many 32-bit architectures. 820ba14a194SAndy Lutomirski 821ba14a194SAndy Lutomirski - Stacks in vmalloc space need to work reliably. For example, if 822ba14a194SAndy Lutomirski vmap page tables are created on demand, either this mechanism 823ba14a194SAndy Lutomirski needs to work while the stack points to a virtual address with 824ba14a194SAndy Lutomirski unpopulated page tables or arch code (switch_to() and switch_mm(), 825ba14a194SAndy Lutomirski most likely) needs to ensure that the stack's page table entries 826ba14a194SAndy Lutomirski are populated before running on a possibly unpopulated stack. 827ba14a194SAndy Lutomirski 828ba14a194SAndy Lutomirski - If the stack overflows into a guard page, something reasonable 829ba14a194SAndy Lutomirski should happen. The definition of "reasonable" is flexible, but 830ba14a194SAndy Lutomirski instantly rebooting without logging anything would be unfriendly. 831ba14a194SAndy Lutomirski 832ba14a194SAndy Lutomirskiconfig VMAP_STACK 833ba14a194SAndy Lutomirski default y 834ba14a194SAndy Lutomirski bool "Use a virtually-mapped stack" 835ba14a194SAndy Lutomirski depends on HAVE_ARCH_VMAP_STACK && !KASAN 836ba14a194SAndy Lutomirski ---help--- 837ba14a194SAndy Lutomirski Enable this if you want the use virtually-mapped kernel stacks 838ba14a194SAndy Lutomirski with guard pages. This causes kernel stack overflows to be 839ba14a194SAndy Lutomirski caught immediately rather than causing difficult-to-diagnose 840ba14a194SAndy Lutomirski corruption. 841ba14a194SAndy Lutomirski 842ba14a194SAndy Lutomirski This is presently incompatible with KASAN because KASAN expects 843ba14a194SAndy Lutomirski the stack to map directly to the KASAN shadow map using a formula 844ba14a194SAndy Lutomirski that is incorrect if the stack is in vmalloc space. 845ba14a194SAndy Lutomirski 846ad21fc4fSLaura Abbottconfig ARCH_OPTIONAL_KERNEL_RWX 847ad21fc4fSLaura Abbott def_bool n 848ad21fc4fSLaura Abbott 849ad21fc4fSLaura Abbottconfig ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 850ad21fc4fSLaura Abbott def_bool n 851ad21fc4fSLaura Abbott 852ad21fc4fSLaura Abbottconfig ARCH_HAS_STRICT_KERNEL_RWX 853ad21fc4fSLaura Abbott def_bool n 854ad21fc4fSLaura Abbott 8550f5bf6d0SLaura Abbottconfig STRICT_KERNEL_RWX 856ad21fc4fSLaura Abbott bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX 857ad21fc4fSLaura Abbott depends on ARCH_HAS_STRICT_KERNEL_RWX 858ad21fc4fSLaura Abbott default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 859ad21fc4fSLaura Abbott help 860ad21fc4fSLaura Abbott If this is set, kernel text and rodata memory will be made read-only, 861ad21fc4fSLaura Abbott and non-text memory will be made non-executable. This provides 862ad21fc4fSLaura Abbott protection against certain security exploits (e.g. executing the heap 863ad21fc4fSLaura Abbott or modifying text) 864ad21fc4fSLaura Abbott 865ad21fc4fSLaura Abbott These features are considered standard security practice these days. 866ad21fc4fSLaura Abbott You should say Y here in almost all cases. 867ad21fc4fSLaura Abbott 868ad21fc4fSLaura Abbottconfig ARCH_HAS_STRICT_MODULE_RWX 869ad21fc4fSLaura Abbott def_bool n 870ad21fc4fSLaura Abbott 8710f5bf6d0SLaura Abbottconfig STRICT_MODULE_RWX 872ad21fc4fSLaura Abbott bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX 873ad21fc4fSLaura Abbott depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES 874ad21fc4fSLaura Abbott default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 875ad21fc4fSLaura Abbott help 876ad21fc4fSLaura Abbott If this is set, module text and rodata memory will be made read-only, 877ad21fc4fSLaura Abbott and non-text memory will be made non-executable. This provides 878ad21fc4fSLaura Abbott protection against certain security exploits (e.g. writing to text) 879ad21fc4fSLaura Abbott 880ea8c64acSChristoph Hellwig# select if the architecture provides an asm/dma-direct.h header 881ea8c64acSChristoph Hellwigconfig ARCH_HAS_PHYS_TO_DMA 882ea8c64acSChristoph Hellwig bool 883ea8c64acSChristoph Hellwig 8847a46ec0eSKees Cookconfig ARCH_HAS_REFCOUNT 8857a46ec0eSKees Cook bool 8867a46ec0eSKees Cook help 8877a46ec0eSKees Cook An architecture selects this when it has implemented refcount_t 8887a46ec0eSKees Cook using open coded assembly primitives that provide an optimized 8897a46ec0eSKees Cook refcount_t implementation, possibly at the expense of some full 8907a46ec0eSKees Cook refcount state checks of CONFIG_REFCOUNT_FULL=y. 8917a46ec0eSKees Cook 8927a46ec0eSKees Cook The refcount overflow check behavior, however, must be retained. 8937a46ec0eSKees Cook Catching overflows is the primary security concern for protecting 8947a46ec0eSKees Cook against bugs in reference counts. 8957a46ec0eSKees Cook 896fd25d19fSKees Cookconfig REFCOUNT_FULL 897fd25d19fSKees Cook bool "Perform full reference count validation at the expense of speed" 898fd25d19fSKees Cook help 899fd25d19fSKees Cook Enabling this switches the refcounting infrastructure from a fast 900fd25d19fSKees Cook unchecked atomic_t implementation to a fully state checked 901fd25d19fSKees Cook implementation, which can be (slightly) slower but provides protections 902fd25d19fSKees Cook against various use-after-free conditions that can be used in 903fd25d19fSKees Cook security flaw exploits. 904fd25d19fSKees Cook 90504f264d3SPaul Burtonconfig HAVE_ARCH_COMPILER_H 90604f264d3SPaul Burton bool 90704f264d3SPaul Burton help 90804f264d3SPaul Burton An architecture can select this if it provides an 90904f264d3SPaul Burton asm/compiler.h header that should be included after 91004f264d3SPaul Burton linux/compiler-*.h in order to override macro definitions that those 91104f264d3SPaul Burton headers generally provide. 91204f264d3SPaul Burton 913271ca788SArd Biesheuvelconfig HAVE_ARCH_PREL32_RELOCATIONS 914271ca788SArd Biesheuvel bool 915271ca788SArd Biesheuvel help 916271ca788SArd Biesheuvel May be selected by an architecture if it supports place-relative 917271ca788SArd Biesheuvel 32-bit relocations, both in the toolchain and in the module loader, 918271ca788SArd Biesheuvel in which case relative references can be used in special sections 919271ca788SArd Biesheuvel for PCI fixup, initcalls etc which are only half the size on 64 bit 920271ca788SArd Biesheuvel architectures, and don't require runtime relocation on relocatable 921271ca788SArd Biesheuvel kernels. 922271ca788SArd Biesheuvel 923ce9084baSArd Biesheuvelconfig ARCH_USE_MEMREMAP_PROT 924ce9084baSArd Biesheuvel bool 925ce9084baSArd Biesheuvel 926fb346fd9SWaiman Longconfig LOCK_EVENT_COUNTS 927fb346fd9SWaiman Long bool "Locking event counts collection" 928fb346fd9SWaiman Long depends on DEBUG_FS 929fb346fd9SWaiman Long ---help--- 930fb346fd9SWaiman Long Enable light-weight counting of various locking related events 931fb346fd9SWaiman Long in the system with minimal performance impact. This reduces 932fb346fd9SWaiman Long the chance of application behavior change because of timing 933fb346fd9SWaiman Long differences. The counts are reported via debugfs. 934fb346fd9SWaiman Long 9352521f2c2SPeter Oberparleitersource "kernel/gcov/Kconfig" 93645332b1bSMasahiro Yamada 93745332b1bSMasahiro Yamadasource "scripts/gcc-plugins/Kconfig" 938fa1b5d09SLinus Torvalds 93922471e13SRandy Dunlapendmenu 940