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 27da32b581SCatalin Marinasconfig ARCH_HAS_SUBPAGE_FAULTS 28da32b581SCatalin Marinas bool 29da32b581SCatalin Marinas help 30da32b581SCatalin Marinas Select if the architecture can check permissions at sub-page 31da32b581SCatalin Marinas granularity (e.g. arm64 MTE). The probe_user_*() functions 32da32b581SCatalin Marinas must be implemented. 33da32b581SCatalin Marinas 3405736e4aSThomas Gleixnerconfig HOTPLUG_SMT 3505736e4aSThomas Gleixner bool 3605736e4aSThomas Gleixner 37142781e1SThomas Gleixnerconfig GENERIC_ENTRY 38142781e1SThomas Gleixner bool 39142781e1SThomas Gleixner 40125e5645SMathieu Desnoyersconfig KPROBES 41125e5645SMathieu Desnoyers bool "Kprobes" 4205ed160eSMasami Hiramatsu depends on MODULES 43125e5645SMathieu Desnoyers depends on HAVE_KPROBES 4405ed160eSMasami Hiramatsu select KALLSYMS 45835f14edSPaul E. McKenney select TASKS_RCU if PREEMPTION 46125e5645SMathieu Desnoyers help 47125e5645SMathieu Desnoyers Kprobes allows you to trap at almost any kernel address and 48125e5645SMathieu Desnoyers execute a callback function. register_kprobe() establishes 49125e5645SMathieu Desnoyers a probepoint and specifies the callback. Kprobes is useful 50125e5645SMathieu Desnoyers for kernel debugging, non-intrusive instrumentation and testing. 51125e5645SMathieu Desnoyers If in doubt, say "N". 52125e5645SMathieu Desnoyers 5345f81b1cSSteven Rostedtconfig JUMP_LABEL 54c5905afbSIngo Molnar bool "Optimize very unlikely/likely branches" 5545f81b1cSSteven Rostedt depends on HAVE_ARCH_JUMP_LABEL 564ab7674fSJosh Poimboeuf select OBJTOOL if HAVE_JUMP_LABEL_HACK 5745f81b1cSSteven Rostedt help 58c5905afbSIngo Molnar This option enables a transparent branch optimization that 59c5905afbSIngo Molnar makes certain almost-always-true or almost-always-false branch 60c5905afbSIngo Molnar conditions even cheaper to execute within the kernel. 6145f81b1cSSteven Rostedt 62c5905afbSIngo Molnar Certain performance-sensitive kernel code, such as trace points, 63c5905afbSIngo Molnar scheduler functionality, networking code and KVM have such 64c5905afbSIngo Molnar branches and include support for this optimization technique. 65c5905afbSIngo Molnar 66c5905afbSIngo Molnar If it is detected that the compiler has support for "asm goto", 67c5905afbSIngo Molnar the kernel will compile such branches with just a nop 68c5905afbSIngo Molnar instruction. When the condition flag is toggled to true, the 69c5905afbSIngo Molnar nop will be converted to a jump instruction to execute the 70c5905afbSIngo Molnar conditional block of instructions. 71c5905afbSIngo Molnar 72c5905afbSIngo Molnar This technique lowers overhead and stress on the branch prediction 73c5905afbSIngo Molnar of the processor and generally makes the kernel faster. The update 74c5905afbSIngo Molnar of the condition is slower, but those are always very rare. 75c5905afbSIngo Molnar 76c5905afbSIngo Molnar ( On 32-bit x86, the necessary options added to the compiler 77c5905afbSIngo Molnar flags may increase the size of the kernel slightly. ) 7845f81b1cSSteven Rostedt 791987c947SPeter Zijlstraconfig STATIC_KEYS_SELFTEST 801987c947SPeter Zijlstra bool "Static key selftest" 811987c947SPeter Zijlstra depends on JUMP_LABEL 821987c947SPeter Zijlstra help 831987c947SPeter Zijlstra Boot time self-test of the branch patching code. 841987c947SPeter Zijlstra 85f03c4129SPeter Zijlstraconfig STATIC_CALL_SELFTEST 86f03c4129SPeter Zijlstra bool "Static call selftest" 87f03c4129SPeter Zijlstra depends on HAVE_STATIC_CALL 88f03c4129SPeter Zijlstra help 89f03c4129SPeter Zijlstra Boot time self-test of the call patching code. 90f03c4129SPeter Zijlstra 91afd66255SMasami Hiramatsuconfig OPTPROBES 925cc718b9SMasami Hiramatsu def_bool y 935cc718b9SMasami Hiramatsu depends on KPROBES && HAVE_OPTPROBES 9401b1d88bSThomas Gleixner select TASKS_RCU if PREEMPTION 95afd66255SMasami Hiramatsu 96e7dbfe34SMasami Hiramatsuconfig KPROBES_ON_FTRACE 97e7dbfe34SMasami Hiramatsu def_bool y 98e7dbfe34SMasami Hiramatsu depends on KPROBES && HAVE_KPROBES_ON_FTRACE 99e7dbfe34SMasami Hiramatsu depends on DYNAMIC_FTRACE_WITH_REGS 100e7dbfe34SMasami Hiramatsu help 101e7dbfe34SMasami Hiramatsu If function tracer is enabled and the arch supports full 102e7dbfe34SMasami Hiramatsu passing of pt_regs to function tracing, then kprobes can 103e7dbfe34SMasami Hiramatsu optimize on top of function tracing. 104e7dbfe34SMasami Hiramatsu 1052b144498SSrikar Dronamrajuconfig UPROBES 10609294e31SDavid A. Long def_bool n 107e8f4aa60SAllen Pais depends on ARCH_SUPPORTS_UPROBES 1082b144498SSrikar Dronamraju help 1097b2d81d4SIngo Molnar Uprobes is the user-space counterpart to kprobes: they 1107b2d81d4SIngo Molnar enable instrumentation applications (such as 'perf probe') 1117b2d81d4SIngo Molnar to establish unintrusive probes in user-space binaries and 1127b2d81d4SIngo Molnar libraries, by executing handler functions when the probes 1137b2d81d4SIngo Molnar are hit by user-space applications. 1147b2d81d4SIngo Molnar 1157b2d81d4SIngo Molnar ( These probes come in the form of single-byte breakpoints, 1167b2d81d4SIngo Molnar managed by the kernel and kept transparent to the probed 1177b2d81d4SIngo Molnar application. ) 1182b144498SSrikar Dronamraju 119adab66b7SSteven Rostedt (VMware)config HAVE_64BIT_ALIGNED_ACCESS 120adab66b7SSteven Rostedt (VMware) def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS 121adab66b7SSteven Rostedt (VMware) help 122adab66b7SSteven Rostedt (VMware) Some architectures require 64 bit accesses to be 64 bit 123adab66b7SSteven Rostedt (VMware) aligned, which also requires structs containing 64 bit values 124adab66b7SSteven Rostedt (VMware) to be 64 bit aligned too. This includes some 32 bit 125adab66b7SSteven Rostedt (VMware) architectures which can do 64 bit accesses, as well as 64 bit 126adab66b7SSteven Rostedt (VMware) architectures without unaligned access. 127adab66b7SSteven Rostedt (VMware) 128adab66b7SSteven Rostedt (VMware) This symbol should be selected by an architecture if 64 bit 129adab66b7SSteven Rostedt (VMware) accesses are required to be 64 bit aligned in this way even 130adab66b7SSteven Rostedt (VMware) though it is not a 64 bit architecture. 131adab66b7SSteven Rostedt (VMware) 132ba1a297dSLukas Bulwahn See Documentation/core-api/unaligned-memory-access.rst for 133ba1a297dSLukas Bulwahn more information on the topic of unaligned memory accesses. 134adab66b7SSteven Rostedt (VMware) 13558340a07SJohannes Bergconfig HAVE_EFFICIENT_UNALIGNED_ACCESS 1369ba16087SJan Beulich bool 13758340a07SJohannes Berg help 13858340a07SJohannes Berg Some architectures are unable to perform unaligned accesses 13958340a07SJohannes Berg without the use of get_unaligned/put_unaligned. Others are 14058340a07SJohannes Berg unable to perform such accesses efficiently (e.g. trap on 14158340a07SJohannes Berg unaligned access and require fixing it up in the exception 14258340a07SJohannes Berg handler.) 14358340a07SJohannes Berg 14458340a07SJohannes Berg This symbol should be selected by an architecture if it can 14558340a07SJohannes Berg perform unaligned accesses efficiently to allow different 14658340a07SJohannes Berg code paths to be selected for these cases. Some network 14758340a07SJohannes Berg drivers, for example, could opt to not fix up alignment 14858340a07SJohannes Berg problems with received packets if doing so would not help 14958340a07SJohannes Berg much. 15058340a07SJohannes Berg 151c9b54d6fSMauro Carvalho Chehab See Documentation/core-api/unaligned-memory-access.rst for more 15258340a07SJohannes Berg information on the topic of unaligned memory accesses. 15358340a07SJohannes Berg 154cf66bb93SDavid Woodhouseconfig ARCH_USE_BUILTIN_BSWAP 155cf66bb93SDavid Woodhouse bool 156cf66bb93SDavid Woodhouse help 157cf66bb93SDavid Woodhouse Modern versions of GCC (since 4.4) have builtin functions 158cf66bb93SDavid Woodhouse for handling byte-swapping. Using these, instead of the old 159cf66bb93SDavid Woodhouse inline assembler that the architecture code provides in the 160cf66bb93SDavid Woodhouse __arch_bswapXX() macros, allows the compiler to see what's 161cf66bb93SDavid Woodhouse happening and offers more opportunity for optimisation. In 162cf66bb93SDavid Woodhouse particular, the compiler will be able to combine the byteswap 163cf66bb93SDavid Woodhouse with a nearby load or store and use load-and-swap or 164cf66bb93SDavid Woodhouse store-and-swap instructions if the architecture has them. It 165cf66bb93SDavid Woodhouse should almost *never* result in code which is worse than the 166cf66bb93SDavid Woodhouse hand-coded assembler in <asm/swab.h>. But just in case it 167cf66bb93SDavid Woodhouse does, the use of the builtins is optional. 168cf66bb93SDavid Woodhouse 169cf66bb93SDavid Woodhouse Any architecture with load-and-swap or store-and-swap 170cf66bb93SDavid Woodhouse instructions should set this. And it shouldn't hurt to set it 171cf66bb93SDavid Woodhouse on architectures that don't have such instructions. 172cf66bb93SDavid Woodhouse 1739edddaa2SAnanth N Mavinakayanahalliconfig KRETPROBES 1749edddaa2SAnanth N Mavinakayanahalli def_bool y 17573f9b911SMasami Hiramatsu depends on KPROBES && (HAVE_KRETPROBES || HAVE_RETHOOK) 17673f9b911SMasami Hiramatsu 17773f9b911SMasami Hiramatsuconfig KRETPROBE_ON_RETHOOK 17873f9b911SMasami Hiramatsu def_bool y 17973f9b911SMasami Hiramatsu depends on HAVE_RETHOOK 18073f9b911SMasami Hiramatsu depends on KRETPROBES 18173f9b911SMasami Hiramatsu select RETHOOK 1829edddaa2SAnanth N Mavinakayanahalli 1837c68af6eSAvi Kivityconfig USER_RETURN_NOTIFIER 1847c68af6eSAvi Kivity bool 1857c68af6eSAvi Kivity depends on HAVE_USER_RETURN_NOTIFIER 1867c68af6eSAvi Kivity help 1877c68af6eSAvi Kivity Provide a kernel-internal notification when a cpu is about to 1887c68af6eSAvi Kivity switch to user mode. 1897c68af6eSAvi Kivity 19028b2ee20SRik van Rielconfig HAVE_IOREMAP_PROT 1919ba16087SJan Beulich bool 19228b2ee20SRik van Riel 193125e5645SMathieu Desnoyersconfig HAVE_KPROBES 1949ba16087SJan Beulich bool 1959edddaa2SAnanth N Mavinakayanahalli 1969edddaa2SAnanth N Mavinakayanahalliconfig HAVE_KRETPROBES 1979ba16087SJan Beulich bool 19874bc7ceeSArthur Kepner 199afd66255SMasami Hiramatsuconfig HAVE_OPTPROBES 200afd66255SMasami Hiramatsu bool 201d314d74cSCong Wang 202e7dbfe34SMasami Hiramatsuconfig HAVE_KPROBES_ON_FTRACE 203e7dbfe34SMasami Hiramatsu bool 204e7dbfe34SMasami Hiramatsu 2051f6d3a8fSMasami Hiramatsuconfig ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 2061f6d3a8fSMasami Hiramatsu bool 2071f6d3a8fSMasami Hiramatsu help 2081f6d3a8fSMasami Hiramatsu Since kretprobes modifies return address on the stack, the 2091f6d3a8fSMasami Hiramatsu stacktrace may see the kretprobe trampoline address instead 2101f6d3a8fSMasami Hiramatsu of correct one. If the architecture stacktrace code and 2111f6d3a8fSMasami Hiramatsu unwinder can adjust such entries, select this configuration. 2121f6d3a8fSMasami Hiramatsu 213540adea3SMasami Hiramatsuconfig HAVE_FUNCTION_ERROR_INJECTION 2149802d865SJosef Bacik bool 2159802d865SJosef Bacik 21642a0bb3fSPetr Mladekconfig HAVE_NMI 21742a0bb3fSPetr Mladek bool 21842a0bb3fSPetr Mladek 219a257caccSChristophe Leroyconfig HAVE_FUNCTION_DESCRIPTORS 220a257caccSChristophe Leroy bool 221a257caccSChristophe Leroy 2224aae683fSMasahiro Yamadaconfig TRACE_IRQFLAGS_SUPPORT 2234aae683fSMasahiro Yamada bool 2244aae683fSMasahiro Yamada 2254510bffbSMark Rutlandconfig TRACE_IRQFLAGS_NMI_SUPPORT 2264510bffbSMark Rutland bool 2274510bffbSMark Rutland 2281f5a4ad9SRoland McGrath# 2291f5a4ad9SRoland McGrath# An arch should select this if it provides all these things: 2301f5a4ad9SRoland McGrath# 2311f5a4ad9SRoland McGrath# task_pt_regs() in asm/processor.h or asm/ptrace.h 2321f5a4ad9SRoland McGrath# arch_has_single_step() if there is hardware single-step support 2331f5a4ad9SRoland McGrath# arch_has_block_step() if there is hardware block-step support 2341f5a4ad9SRoland McGrath# asm/syscall.h supplying asm-generic/syscall.h interface 2351f5a4ad9SRoland McGrath# linux/regset.h user_regset interfaces 2361f5a4ad9SRoland McGrath# CORE_DUMP_USE_REGSET #define'd in linux/elf.h 237153474baSEric W. Biederman# TIF_SYSCALL_TRACE calls ptrace_report_syscall_{entry,exit} 23803248addSEric W. Biederman# TIF_NOTIFY_RESUME calls resume_user_mode_work() 2391f5a4ad9SRoland McGrath# 2401f5a4ad9SRoland McGrathconfig HAVE_ARCH_TRACEHOOK 2419ba16087SJan Beulich bool 2421f5a4ad9SRoland McGrath 243c64be2bbSMarek Szyprowskiconfig HAVE_DMA_CONTIGUOUS 244c64be2bbSMarek Szyprowski bool 245c64be2bbSMarek Szyprowski 24629d5e047SThomas Gleixnerconfig GENERIC_SMP_IDLE_THREAD 24729d5e047SThomas Gleixner bool 24829d5e047SThomas Gleixner 249485cf5daSKevin Hilmanconfig GENERIC_IDLE_POLL_SETUP 250485cf5daSKevin Hilman bool 251485cf5daSKevin Hilman 2526974f0c4SDaniel Micayconfig ARCH_HAS_FORTIFY_SOURCE 2536974f0c4SDaniel Micay bool 2546974f0c4SDaniel Micay help 2556974f0c4SDaniel Micay An architecture should select this when it can successfully 2566974f0c4SDaniel Micay build and run with CONFIG_FORTIFY_SOURCE. 2576974f0c4SDaniel Micay 258d8ae8a37SChristoph Hellwig# 259d8ae8a37SChristoph Hellwig# Select if the arch provides a historic keepinit alias for the retain_initrd 260d8ae8a37SChristoph Hellwig# command line option 261d8ae8a37SChristoph Hellwig# 262d8ae8a37SChristoph Hellwigconfig ARCH_HAS_KEEPINITRD 263d8ae8a37SChristoph Hellwig bool 264d8ae8a37SChristoph Hellwig 265d2852a22SDaniel Borkmann# Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h 266d2852a22SDaniel Borkmannconfig ARCH_HAS_SET_MEMORY 267d2852a22SDaniel Borkmann bool 268d2852a22SDaniel Borkmann 269d253ca0cSRick Edgecombe# Select if arch has all set_direct_map_invalid/default() functions 270d253ca0cSRick Edgecombeconfig ARCH_HAS_SET_DIRECT_MAP 271d253ca0cSRick Edgecombe bool 272d253ca0cSRick Edgecombe 273c30700dbSChristoph Hellwig# 274fa7e2247SChristoph Hellwig# Select if the architecture provides the arch_dma_set_uncached symbol to 275a86ecfa6SColin Ian King# either provide an uncached segment alias for a DMA allocation, or 276fa7e2247SChristoph Hellwig# to remap the page tables in place. 277c30700dbSChristoph Hellwig# 278fa7e2247SChristoph Hellwigconfig ARCH_HAS_DMA_SET_UNCACHED 279c30700dbSChristoph Hellwig bool 280c30700dbSChristoph Hellwig 281999a5d12SChristoph Hellwig# 282999a5d12SChristoph Hellwig# Select if the architectures provides the arch_dma_clear_uncached symbol 283999a5d12SChristoph Hellwig# to undo an in-place page table remap for uncached access. 284999a5d12SChristoph Hellwig# 285999a5d12SChristoph Hellwigconfig ARCH_HAS_DMA_CLEAR_UNCACHED 286f5e10287SThomas Gleixner bool 287f5e10287SThomas Gleixner 2885905429aSKees Cook# Select if arch init_task must go in the __init_task_data section 2895905429aSKees Cookconfig ARCH_TASK_STRUCT_ON_STACK 2905905429aSKees Cook bool 2915905429aSKees Cook 2925905429aSKees Cook# Select if arch has its private alloc_task_struct() function 2935905429aSKees Cookconfig ARCH_TASK_STRUCT_ALLOCATOR 2945905429aSKees Cook bool 2955905429aSKees Cook 2965905429aSKees Cookconfig HAVE_ARCH_THREAD_STRUCT_WHITELIST 2975905429aSKees Cook bool 2985905429aSKees Cook depends on !ARCH_TASK_STRUCT_ALLOCATOR 299b235beeaSLinus Torvalds help 300b235beeaSLinus Torvalds An architecture should select this to provide hardened usercopy 301f5e10287SThomas Gleixner knowledge about what region of the thread_struct should be 302f5e10287SThomas Gleixner whitelisted for copying to userspace. Normally this is only the 3035aaeb5c0SIngo Molnar FPU registers. Specifically, arch_thread_struct_whitelist() 3045aaeb5c0SIngo Molnar should be implemented. Without this, the entire thread_struct 3055aaeb5c0SIngo Molnar field in task_struct will be left whitelisted. 3065aaeb5c0SIngo Molnar 307942fa985SYury Norov# Select if arch has its private alloc_thread_stack() function 308942fa985SYury Norovconfig ARCH_THREAD_STACK_ALLOCATOR 309942fa985SYury Norov bool 310942fa985SYury Norov 311942fa985SYury Norov# Select if arch wants to size task_struct dynamically via arch_task_struct_size: 312942fa985SYury Norovconfig ARCH_WANTS_DYNAMIC_TASK_STRUCT 313942fa985SYury Norov bool 314942fa985SYury Norov 31551c2ee6dSNick Desaulniersconfig ARCH_WANTS_NO_INSTR 31651c2ee6dSNick Desaulniers bool 31751c2ee6dSNick Desaulniers help 31851c2ee6dSNick Desaulniers An architecture should select this if the noinstr macro is being used on 31951c2ee6dSNick Desaulniers functions to denote that the toolchain should avoid instrumenting such 32051c2ee6dSNick Desaulniers functions and is required for correctness. 32151c2ee6dSNick Desaulniers 322942fa985SYury Norovconfig ARCH_32BIT_OFF_T 323942fa985SYury Norov bool 324942fa985SYury Norov depends on !64BIT 325942fa985SYury Norov help 326942fa985SYury Norov All new 32-bit architectures should have 64-bit off_t type on 327942fa985SYury Norov userspace side which corresponds to the loff_t kernel type. This 328942fa985SYury Norov is the requirement for modern ABIs. Some existing architectures 329942fa985SYury Norov still support 32-bit off_t. This option is enabled for all such 330942fa985SYury Norov architectures explicitly. 331942fa985SYury Norov 33296c0a6a7SHeiko Carstens# Selected by 64 bit architectures which have a 32 bit f_tinode in struct ustat 33396c0a6a7SHeiko Carstensconfig ARCH_32BIT_USTAT_F_TINODE 33496c0a6a7SHeiko Carstens bool 33596c0a6a7SHeiko Carstens 3362ff2b7ecSMasahiro Yamadaconfig HAVE_ASM_MODVERSIONS 3372ff2b7ecSMasahiro Yamada bool 3382ff2b7ecSMasahiro Yamada help 339a86ecfa6SColin Ian King This symbol should be selected by an architecture if it provides 3402ff2b7ecSMasahiro Yamada <asm/asm-prototypes.h> to support the module versioning for symbols 3412ff2b7ecSMasahiro Yamada exported from assembly code. 3422ff2b7ecSMasahiro Yamada 343f850c30cSHeiko Carstensconfig HAVE_REGS_AND_STACK_ACCESS_API 344f850c30cSHeiko Carstens bool 345e01292b1SHeiko Carstens help 346a86ecfa6SColin Ian King This symbol should be selected by an architecture if it supports 347e01292b1SHeiko Carstens the API needed to access registers and stack entries from pt_regs, 348e01292b1SHeiko Carstens declared in asm/ptrace.h 349e01292b1SHeiko Carstens For example the kprobes-based event tracer needs this API. 350f850c30cSHeiko Carstens 351d7822b1eSMathieu Desnoyersconfig HAVE_RSEQ 352d7822b1eSMathieu Desnoyers bool 353d7822b1eSMathieu Desnoyers depends on HAVE_REGS_AND_STACK_ACCESS_API 354d7822b1eSMathieu Desnoyers help 355d7822b1eSMathieu Desnoyers This symbol should be selected by an architecture if it 356d7822b1eSMathieu Desnoyers supports an implementation of restartable sequences. 357d7822b1eSMathieu Desnoyers 3582f7ab126SMiguel Ojedaconfig HAVE_RUST 3592f7ab126SMiguel Ojeda bool 3602f7ab126SMiguel Ojeda help 3612f7ab126SMiguel Ojeda This symbol should be selected by an architecture if it 3622f7ab126SMiguel Ojeda supports Rust. 3632f7ab126SMiguel Ojeda 3643c88ee19SMasami Hiramatsuconfig HAVE_FUNCTION_ARG_ACCESS_API 3653c88ee19SMasami Hiramatsu bool 3663c88ee19SMasami Hiramatsu help 367a86ecfa6SColin Ian King This symbol should be selected by an architecture if it supports 3683c88ee19SMasami Hiramatsu the API needed to access function arguments from pt_regs, 3693c88ee19SMasami Hiramatsu declared in asm/ptrace.h 3703c88ee19SMasami Hiramatsu 37162a038d3SK.Prasadconfig HAVE_HW_BREAKPOINT 37262a038d3SK.Prasad bool 37399e8c5a3SFrederic Weisbecker depends on PERF_EVENTS 37462a038d3SK.Prasad 3750102752eSFrederic Weisbeckerconfig HAVE_MIXED_BREAKPOINTS_REGS 3760102752eSFrederic Weisbecker bool 3770102752eSFrederic Weisbecker depends on HAVE_HW_BREAKPOINT 3780102752eSFrederic Weisbecker help 3790102752eSFrederic Weisbecker Depending on the arch implementation of hardware breakpoints, 3800102752eSFrederic Weisbecker some of them have separate registers for data and instruction 3810102752eSFrederic Weisbecker breakpoints addresses, others have mixed registers to store 3820102752eSFrederic Weisbecker them but define the access type in a control register. 3830102752eSFrederic Weisbecker Select this option if your arch implements breakpoints under the 3840102752eSFrederic Weisbecker latter fashion. 3850102752eSFrederic Weisbecker 3867c68af6eSAvi Kivityconfig HAVE_USER_RETURN_NOTIFIER 3877c68af6eSAvi Kivity bool 388a1922ed6SIngo Molnar 389c01d4323SFrederic Weisbeckerconfig HAVE_PERF_EVENTS_NMI 390c01d4323SFrederic Weisbecker bool 39123637d47SFrederic Weisbecker help 39223637d47SFrederic Weisbecker System hardware can generate an NMI using the perf event 39323637d47SFrederic Weisbecker subsystem. Also has support for calculating CPU cycle events 39423637d47SFrederic Weisbecker to determine how many clock cycles in a given period. 395c01d4323SFrederic Weisbecker 39605a4a952SNicholas Pigginconfig HAVE_HARDLOCKUP_DETECTOR_PERF 39705a4a952SNicholas Piggin bool 39805a4a952SNicholas Piggin depends on HAVE_PERF_EVENTS_NMI 39905a4a952SNicholas Piggin help 40005a4a952SNicholas Piggin The arch chooses to use the generic perf-NMI-based hardlockup 40105a4a952SNicholas Piggin detector. Must define HAVE_PERF_EVENTS_NMI. 40205a4a952SNicholas Piggin 40305a4a952SNicholas Pigginconfig HAVE_NMI_WATCHDOG 40405a4a952SNicholas Piggin depends on HAVE_NMI 40505a4a952SNicholas Piggin bool 40605a4a952SNicholas Piggin help 40705a4a952SNicholas Piggin The arch provides a low level NMI watchdog. It provides 40805a4a952SNicholas Piggin asm/nmi.h, and defines its own arch_touch_nmi_watchdog(). 40905a4a952SNicholas Piggin 41005a4a952SNicholas Pigginconfig HAVE_HARDLOCKUP_DETECTOR_ARCH 41105a4a952SNicholas Piggin bool 41205a4a952SNicholas Piggin select HAVE_NMI_WATCHDOG 41305a4a952SNicholas Piggin help 41405a4a952SNicholas Piggin The arch chooses to provide its own hardlockup detector, which is 41505a4a952SNicholas Piggin a superset of the HAVE_NMI_WATCHDOG. It also conforms to config 41605a4a952SNicholas Piggin interfaces and parameters provided by hardlockup detector subsystem. 41705a4a952SNicholas Piggin 418c5e63197SJiri Olsaconfig HAVE_PERF_REGS 419c5e63197SJiri Olsa bool 420c5e63197SJiri Olsa help 421c5e63197SJiri Olsa Support selective register dumps for perf events. This includes 422c5e63197SJiri Olsa bit-mapping of each registers and a unique architecture id. 423c5e63197SJiri Olsa 424c5ebcedbSJiri Olsaconfig HAVE_PERF_USER_STACK_DUMP 425c5ebcedbSJiri Olsa bool 426c5ebcedbSJiri Olsa help 427c5ebcedbSJiri Olsa Support user stack dumps for perf event samples. This needs 428c5ebcedbSJiri Olsa access to the user stack pointer which is not unified across 429c5ebcedbSJiri Olsa architectures. 430c5ebcedbSJiri Olsa 431bf5438fcSJason Baronconfig HAVE_ARCH_JUMP_LABEL 432bf5438fcSJason Baron bool 433bf5438fcSJason Baron 43450ff18abSArd Biesheuvelconfig HAVE_ARCH_JUMP_LABEL_RELATIVE 43550ff18abSArd Biesheuvel bool 43650ff18abSArd Biesheuvel 4370d6e24d4SPeter Zijlstraconfig MMU_GATHER_TABLE_FREE 4380d6e24d4SPeter Zijlstra bool 4390d6e24d4SPeter Zijlstra 440ff2e6d72SPeter Zijlstraconfig MMU_GATHER_RCU_TABLE_FREE 44126723911SPeter Zijlstra bool 4420d6e24d4SPeter Zijlstra select MMU_GATHER_TABLE_FREE 44326723911SPeter Zijlstra 4443af4bd03SPeter Zijlstraconfig MMU_GATHER_PAGE_SIZE 445ed6a7935SPeter Zijlstra bool 446ed6a7935SPeter Zijlstra 44727796d03SPeter Zijlstraconfig MMU_GATHER_NO_RANGE 44827796d03SPeter Zijlstra bool 4491e9fdf21SPeter Zijlstra select MMU_GATHER_MERGE_VMAS 4501e9fdf21SPeter Zijlstra 4511e9fdf21SPeter Zijlstraconfig MMU_GATHER_NO_FLUSH_CACHE 4521e9fdf21SPeter Zijlstra bool 4531e9fdf21SPeter Zijlstra 4541e9fdf21SPeter Zijlstraconfig MMU_GATHER_MERGE_VMAS 4551e9fdf21SPeter Zijlstra bool 45627796d03SPeter Zijlstra 457580a586cSPeter Zijlstraconfig MMU_GATHER_NO_GATHER 458952a31c9SMartin Schwidefsky bool 4590d6e24d4SPeter Zijlstra depends on MMU_GATHER_TABLE_FREE 460952a31c9SMartin Schwidefsky 461d53c3dfbSNicholas Pigginconfig ARCH_WANT_IRQS_OFF_ACTIVATE_MM 462d53c3dfbSNicholas Piggin bool 463d53c3dfbSNicholas Piggin help 464d53c3dfbSNicholas Piggin Temporary select until all architectures can be converted to have 465d53c3dfbSNicholas Piggin irqs disabled over activate_mm. Architectures that do IPI based TLB 466d53c3dfbSNicholas Piggin shootdowns should enable this. 467d53c3dfbSNicholas Piggin 468*88e3009bSNicholas Piggin# Use normal mm refcounting for MMU_LAZY_TLB kernel thread references. 469*88e3009bSNicholas Piggin# MMU_LAZY_TLB_REFCOUNT=n can improve the scalability of context switching 470*88e3009bSNicholas Piggin# to/from kernel threads when the same mm is running on a lot of CPUs (a large 471*88e3009bSNicholas Piggin# multi-threaded application), by reducing contention on the mm refcount. 472*88e3009bSNicholas Piggin# 473*88e3009bSNicholas Piggin# This can be disabled if the architecture ensures no CPUs are using an mm as a 474*88e3009bSNicholas Piggin# "lazy tlb" beyond its final refcount (i.e., by the time __mmdrop frees the mm 475*88e3009bSNicholas Piggin# or its kernel page tables). This could be arranged by arch_exit_mmap(), or 476*88e3009bSNicholas Piggin# final exit(2) TLB flush, for example. 477*88e3009bSNicholas Piggin# 478*88e3009bSNicholas Piggin# To implement this, an arch *must*: 479*88e3009bSNicholas Piggin# Ensure the _lazy_tlb variants of mmgrab/mmdrop are used when manipulating 480*88e3009bSNicholas Piggin# the lazy tlb reference of a kthread's ->active_mm (non-arch code has been 481*88e3009bSNicholas Piggin# converted already). 482*88e3009bSNicholas Pigginconfig MMU_LAZY_TLB_REFCOUNT 483*88e3009bSNicholas Piggin def_bool y 484*88e3009bSNicholas Piggin 485df013ffbSHuang Yingconfig ARCH_HAVE_NMI_SAFE_CMPXCHG 486df013ffbSHuang Ying bool 487df013ffbSHuang Ying 4882e83b879SPaul E. McKenneyconfig ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 4892e83b879SPaul E. McKenney bool 4902e83b879SPaul E. McKenney 49143570fd2SHeiko Carstensconfig HAVE_ALIGNED_STRUCT_PAGE 49243570fd2SHeiko Carstens bool 49343570fd2SHeiko Carstens help 49443570fd2SHeiko Carstens This makes sure that struct pages are double word aligned and that 49543570fd2SHeiko Carstens e.g. the SLUB allocator can perform double word atomic operations 49643570fd2SHeiko Carstens on a struct page for better performance. However selecting this 49743570fd2SHeiko Carstens might increase the size of a struct page by a word. 49843570fd2SHeiko Carstens 4994156153cSHeiko Carstensconfig HAVE_CMPXCHG_LOCAL 5004156153cSHeiko Carstens bool 5014156153cSHeiko Carstens 5022565409fSHeiko Carstensconfig HAVE_CMPXCHG_DOUBLE 5032565409fSHeiko Carstens bool 5042565409fSHeiko Carstens 50577e58496SPaul E. McKenneyconfig ARCH_WEAK_RELEASE_ACQUIRE 50677e58496SPaul E. McKenney bool 50777e58496SPaul E. McKenney 508c1d7e01dSWill Deaconconfig ARCH_WANT_IPC_PARSE_VERSION 509c1d7e01dSWill Deacon bool 510c1d7e01dSWill Deacon 511c1d7e01dSWill Deaconconfig ARCH_WANT_COMPAT_IPC_PARSE_VERSION 512c1d7e01dSWill Deacon bool 513c1d7e01dSWill Deacon 51448b25c43SChris Metcalfconfig ARCH_WANT_OLD_COMPAT_IPC 515c1d7e01dSWill Deacon select ARCH_WANT_COMPAT_IPC_PARSE_VERSION 51648b25c43SChris Metcalf bool 51748b25c43SChris Metcalf 518282a181bSYiFei Zhuconfig HAVE_ARCH_SECCOMP 519e2cfabdfSWill Drewry bool 520e2cfabdfSWill Drewry help 521282a181bSYiFei Zhu An arch should select this symbol to support seccomp mode 1 (the fixed 522282a181bSYiFei Zhu syscall policy), and must provide an overrides for __NR_seccomp_sigreturn, 523282a181bSYiFei Zhu and compat syscalls if the asm-generic/seccomp.h defaults need adjustment: 524282a181bSYiFei Zhu - __NR_seccomp_read_32 525282a181bSYiFei Zhu - __NR_seccomp_write_32 526282a181bSYiFei Zhu - __NR_seccomp_exit_32 527282a181bSYiFei Zhu - __NR_seccomp_sigreturn_32 528282a181bSYiFei Zhu 529282a181bSYiFei Zhuconfig HAVE_ARCH_SECCOMP_FILTER 530282a181bSYiFei Zhu bool 531282a181bSYiFei Zhu select HAVE_ARCH_SECCOMP 532282a181bSYiFei Zhu help 533fb0fadf9SWill Drewry An arch should select this symbol if it provides all of these things: 534282a181bSYiFei Zhu - all the requirements for HAVE_ARCH_SECCOMP 535bb6ea430SWill Drewry - syscall_get_arch() 536bb6ea430SWill Drewry - syscall_get_arguments() 537bb6ea430SWill Drewry - syscall_rollback() 538bb6ea430SWill Drewry - syscall_set_return_value() 539fb0fadf9SWill Drewry - SIGSYS siginfo_t support 540fb0fadf9SWill Drewry - secure_computing is called from a ptrace_event()-safe context 541fb0fadf9SWill Drewry - secure_computing return value is checked and a return value of -1 542fb0fadf9SWill Drewry results in the system call being skipped immediately. 54348dc92b9SKees Cook - seccomp syscall wired up 5440d8315ddSYiFei Zhu - if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE, 5450d8315ddSYiFei Zhu SECCOMP_ARCH_NATIVE_NR, SECCOMP_ARCH_NATIVE_NAME defined. If 5460d8315ddSYiFei Zhu COMPAT is supported, have the SECCOMP_ARCH_COMPAT* defines too. 547e2cfabdfSWill Drewry 548282a181bSYiFei Zhuconfig SECCOMP 549282a181bSYiFei Zhu prompt "Enable seccomp to safely execute untrusted bytecode" 550282a181bSYiFei Zhu def_bool y 551282a181bSYiFei Zhu depends on HAVE_ARCH_SECCOMP 552282a181bSYiFei Zhu help 553282a181bSYiFei Zhu This kernel feature is useful for number crunching applications 554282a181bSYiFei Zhu that may need to handle untrusted bytecode during their 555282a181bSYiFei Zhu execution. By using pipes or other transports made available 556282a181bSYiFei Zhu to the process as file descriptors supporting the read/write 557282a181bSYiFei Zhu syscalls, it's possible to isolate those applications in their 558282a181bSYiFei Zhu own address space using seccomp. Once seccomp is enabled via 559282a181bSYiFei Zhu prctl(PR_SET_SECCOMP) or the seccomp() syscall, it cannot be 560282a181bSYiFei Zhu disabled and the task is only allowed to execute a few safe 561282a181bSYiFei Zhu syscalls defined by each seccomp mode. 562282a181bSYiFei Zhu 563282a181bSYiFei Zhu If unsure, say Y. 564282a181bSYiFei Zhu 565e2cfabdfSWill Drewryconfig SECCOMP_FILTER 566e2cfabdfSWill Drewry def_bool y 567e2cfabdfSWill Drewry depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET 568e2cfabdfSWill Drewry help 569e2cfabdfSWill Drewry Enable tasks to build secure computing environments defined 570e2cfabdfSWill Drewry in terms of Berkeley Packet Filter programs which implement 571e2cfabdfSWill Drewry task-defined system call filtering polices. 572e2cfabdfSWill Drewry 5735fb94e9cSMauro Carvalho Chehab See Documentation/userspace-api/seccomp_filter.rst for details. 574e2cfabdfSWill Drewry 5750d8315ddSYiFei Zhuconfig SECCOMP_CACHE_DEBUG 5760d8315ddSYiFei Zhu bool "Show seccomp filter cache status in /proc/pid/seccomp_cache" 5770d8315ddSYiFei Zhu depends on SECCOMP_FILTER && !HAVE_SPARSE_SYSCALL_NR 5780d8315ddSYiFei Zhu depends on PROC_FS 5790d8315ddSYiFei Zhu help 5800d8315ddSYiFei Zhu This enables the /proc/pid/seccomp_cache interface to monitor 5810d8315ddSYiFei Zhu seccomp cache data. The file format is subject to change. Reading 5820d8315ddSYiFei Zhu the file requires CAP_SYS_ADMIN. 5830d8315ddSYiFei Zhu 5840d8315ddSYiFei Zhu This option is for debugging only. Enabling presents the risk that 5850d8315ddSYiFei Zhu an adversary may be able to infer the seccomp filter logic. 5860d8315ddSYiFei Zhu 5870d8315ddSYiFei Zhu If unsure, say N. 5880d8315ddSYiFei Zhu 589afaef01cSAlexander Popovconfig HAVE_ARCH_STACKLEAK 590afaef01cSAlexander Popov bool 591afaef01cSAlexander Popov help 592afaef01cSAlexander Popov An architecture should select this if it has the code which 593afaef01cSAlexander Popov fills the used part of the kernel stack with the STACKLEAK_POISON 594afaef01cSAlexander Popov value before returning from system calls. 595afaef01cSAlexander Popov 596d148eac0SMasahiro Yamadaconfig HAVE_STACKPROTECTOR 59719952a92SKees Cook bool 59819952a92SKees Cook help 59919952a92SKees Cook An arch should select this symbol if: 60019952a92SKees Cook - it has implemented a stack canary (e.g. __stack_chk_guard) 60119952a92SKees Cook 602050e9baaSLinus Torvaldsconfig STACKPROTECTOR 6032a61f474SMasahiro Yamada bool "Stack Protector buffer overflow detection" 604d148eac0SMasahiro Yamada depends on HAVE_STACKPROTECTOR 6052a61f474SMasahiro Yamada depends on $(cc-option,-fstack-protector) 6062a61f474SMasahiro Yamada default y 6078779657dSKees Cook help 6088779657dSKees Cook This option turns on the "stack-protector" GCC feature. This 60919952a92SKees Cook feature puts, at the beginning of functions, a canary value on 61019952a92SKees Cook the stack just before the return address, and validates 61119952a92SKees Cook the value just before actually returning. Stack based buffer 61219952a92SKees Cook overflows (that need to overwrite this return address) now also 61319952a92SKees Cook overwrite the canary, which gets detected and the attack is then 61419952a92SKees Cook neutralized via a kernel panic. 61519952a92SKees Cook 6168779657dSKees Cook Functions will have the stack-protector canary logic added if they 6178779657dSKees Cook have an 8-byte or larger character array on the stack. 6188779657dSKees Cook 61919952a92SKees Cook This feature requires gcc version 4.2 or above, or a distribution 6208779657dSKees Cook gcc with the feature backported ("-fstack-protector"). 6218779657dSKees Cook 6228779657dSKees Cook On an x86 "defconfig" build, this feature adds canary checks to 6238779657dSKees Cook about 3% of all kernel functions, which increases kernel code size 6248779657dSKees Cook by about 0.3%. 6258779657dSKees Cook 626050e9baaSLinus Torvaldsconfig STACKPROTECTOR_STRONG 6272a61f474SMasahiro Yamada bool "Strong Stack Protector" 628050e9baaSLinus Torvalds depends on STACKPROTECTOR 6292a61f474SMasahiro Yamada depends on $(cc-option,-fstack-protector-strong) 6302a61f474SMasahiro Yamada default y 6318779657dSKees Cook help 6328779657dSKees Cook Functions will have the stack-protector canary logic added in any 6338779657dSKees Cook of the following conditions: 6348779657dSKees Cook 6358779657dSKees Cook - local variable's address used as part of the right hand side of an 6368779657dSKees Cook assignment or function argument 6378779657dSKees Cook - local variable is an array (or union containing an array), 6388779657dSKees Cook regardless of array type or length 6398779657dSKees Cook - uses register local variables 6408779657dSKees Cook 6418779657dSKees Cook This feature requires gcc version 4.9 or above, or a distribution 6428779657dSKees Cook gcc with the feature backported ("-fstack-protector-strong"). 6438779657dSKees Cook 6448779657dSKees Cook On an x86 "defconfig" build, this feature adds canary checks to 6458779657dSKees Cook about 20% of all kernel functions, which increases the kernel code 6468779657dSKees Cook size by about 2%. 6478779657dSKees Cook 648d08b9f0cSSami Tolvanenconfig ARCH_SUPPORTS_SHADOW_CALL_STACK 649d08b9f0cSSami Tolvanen bool 650d08b9f0cSSami Tolvanen help 651afcf5441SDan Li An architecture should select this if it supports the compiler's 652afcf5441SDan Li Shadow Call Stack and implements runtime support for shadow stack 653aa7a65aeSWill Deacon switching. 654d08b9f0cSSami Tolvanen 655d08b9f0cSSami Tolvanenconfig SHADOW_CALL_STACK 656afcf5441SDan Li bool "Shadow Call Stack" 657afcf5441SDan Li depends on ARCH_SUPPORTS_SHADOW_CALL_STACK 65838792972SArd Biesheuvel depends on DYNAMIC_FTRACE_WITH_ARGS || DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER 659d08b9f0cSSami Tolvanen help 660afcf5441SDan Li This option enables the compiler's Shadow Call Stack, which 661afcf5441SDan Li uses a shadow stack to protect function return addresses from 662afcf5441SDan Li being overwritten by an attacker. More information can be found 663afcf5441SDan Li in the compiler's documentation: 664d08b9f0cSSami Tolvanen 665afcf5441SDan Li - Clang: https://clang.llvm.org/docs/ShadowCallStack.html 666afcf5441SDan Li - GCC: https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options 667d08b9f0cSSami Tolvanen 668d08b9f0cSSami Tolvanen Note that security guarantees in the kernel differ from the 669d08b9f0cSSami Tolvanen ones documented for user space. The kernel must store addresses 670d08b9f0cSSami Tolvanen of shadow stacks in memory, which means an attacker capable of 671d08b9f0cSSami Tolvanen reading and writing arbitrary memory may be able to locate them 672d08b9f0cSSami Tolvanen and hijack control flow by modifying the stacks. 673d08b9f0cSSami Tolvanen 6749beccca0SArd Biesheuvelconfig DYNAMIC_SCS 6759beccca0SArd Biesheuvel bool 6769beccca0SArd Biesheuvel help 6779beccca0SArd Biesheuvel Set by the arch code if it relies on code patching to insert the 6789beccca0SArd Biesheuvel shadow call stack push and pop instructions rather than on the 6799beccca0SArd Biesheuvel compiler. 6809beccca0SArd Biesheuvel 681dc5723b0SSami Tolvanenconfig LTO 682dc5723b0SSami Tolvanen bool 683dc5723b0SSami Tolvanen help 684dc5723b0SSami Tolvanen Selected if the kernel will be built using the compiler's LTO feature. 685dc5723b0SSami Tolvanen 686dc5723b0SSami Tolvanenconfig LTO_CLANG 687dc5723b0SSami Tolvanen bool 688dc5723b0SSami Tolvanen select LTO 689dc5723b0SSami Tolvanen help 690dc5723b0SSami Tolvanen Selected if the kernel will be built using Clang's LTO feature. 691dc5723b0SSami Tolvanen 692dc5723b0SSami Tolvanenconfig ARCH_SUPPORTS_LTO_CLANG 693dc5723b0SSami Tolvanen bool 694dc5723b0SSami Tolvanen help 695dc5723b0SSami Tolvanen An architecture should select this option if it supports: 696dc5723b0SSami Tolvanen - compiling with Clang, 697dc5723b0SSami Tolvanen - compiling inline assembly with Clang's integrated assembler, 698dc5723b0SSami Tolvanen - and linking with LLD. 699dc5723b0SSami Tolvanen 700dc5723b0SSami Tolvanenconfig ARCH_SUPPORTS_LTO_CLANG_THIN 701dc5723b0SSami Tolvanen bool 702dc5723b0SSami Tolvanen help 703dc5723b0SSami Tolvanen An architecture should select this option if it can support Clang's 704dc5723b0SSami Tolvanen ThinLTO mode. 705dc5723b0SSami Tolvanen 706dc5723b0SSami Tolvanenconfig HAS_LTO_CLANG 707dc5723b0SSami Tolvanen def_bool y 7081e68a8afSNathan Chancellor depends on CC_IS_CLANG && LD_IS_LLD && AS_IS_LLVM 709dc5723b0SSami Tolvanen depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm) 710dc5723b0SSami Tolvanen depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm) 711dc5723b0SSami Tolvanen depends on ARCH_SUPPORTS_LTO_CLANG 712dc5723b0SSami Tolvanen depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT 713bf3c2551SSami Tolvanen depends on !KASAN || KASAN_HW_TAGS 714dc5723b0SSami Tolvanen depends on !GCOV_KERNEL 715dc5723b0SSami Tolvanen help 716dc5723b0SSami Tolvanen The compiler and Kconfig options support building with Clang's 717dc5723b0SSami Tolvanen LTO. 718dc5723b0SSami Tolvanen 719dc5723b0SSami Tolvanenchoice 720dc5723b0SSami Tolvanen prompt "Link Time Optimization (LTO)" 721dc5723b0SSami Tolvanen default LTO_NONE 722dc5723b0SSami Tolvanen help 723dc5723b0SSami Tolvanen This option enables Link Time Optimization (LTO), which allows the 724dc5723b0SSami Tolvanen compiler to optimize binaries globally. 725dc5723b0SSami Tolvanen 726dc5723b0SSami Tolvanen If unsure, select LTO_NONE. Note that LTO is very resource-intensive 727dc5723b0SSami Tolvanen so it's disabled by default. 728dc5723b0SSami Tolvanen 729dc5723b0SSami Tolvanenconfig LTO_NONE 730dc5723b0SSami Tolvanen bool "None" 731dc5723b0SSami Tolvanen help 732dc5723b0SSami Tolvanen Build the kernel normally, without Link Time Optimization (LTO). 733dc5723b0SSami Tolvanen 734dc5723b0SSami Tolvanenconfig LTO_CLANG_FULL 735dc5723b0SSami Tolvanen bool "Clang Full LTO (EXPERIMENTAL)" 736dc5723b0SSami Tolvanen depends on HAS_LTO_CLANG 737dc5723b0SSami Tolvanen depends on !COMPILE_TEST 738dc5723b0SSami Tolvanen select LTO_CLANG 739dc5723b0SSami Tolvanen help 740dc5723b0SSami Tolvanen This option enables Clang's full Link Time Optimization (LTO), which 741dc5723b0SSami Tolvanen allows the compiler to optimize the kernel globally. If you enable 742dc5723b0SSami Tolvanen this option, the compiler generates LLVM bitcode instead of ELF 743dc5723b0SSami Tolvanen object files, and the actual compilation from bitcode happens at 744dc5723b0SSami Tolvanen the LTO link step, which may take several minutes depending on the 745dc5723b0SSami Tolvanen kernel configuration. More information can be found from LLVM's 746dc5723b0SSami Tolvanen documentation: 747dc5723b0SSami Tolvanen 748dc5723b0SSami Tolvanen https://llvm.org/docs/LinkTimeOptimization.html 749dc5723b0SSami Tolvanen 750dc5723b0SSami Tolvanen During link time, this option can use a large amount of RAM, and 751dc5723b0SSami Tolvanen may take much longer than the ThinLTO option. 752dc5723b0SSami Tolvanen 753dc5723b0SSami Tolvanenconfig LTO_CLANG_THIN 754dc5723b0SSami Tolvanen bool "Clang ThinLTO (EXPERIMENTAL)" 755dc5723b0SSami Tolvanen depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN 756dc5723b0SSami Tolvanen select LTO_CLANG 757dc5723b0SSami Tolvanen help 758dc5723b0SSami Tolvanen This option enables Clang's ThinLTO, which allows for parallel 759dc5723b0SSami Tolvanen optimization and faster incremental compiles compared to the 760dc5723b0SSami Tolvanen CONFIG_LTO_CLANG_FULL option. More information can be found 761dc5723b0SSami Tolvanen from Clang's documentation: 762dc5723b0SSami Tolvanen 763dc5723b0SSami Tolvanen https://clang.llvm.org/docs/ThinLTO.html 764dc5723b0SSami Tolvanen 765dc5723b0SSami Tolvanen If unsure, say Y. 766dc5723b0SSami Tolvanenendchoice 767dc5723b0SSami Tolvanen 768cf68fffbSSami Tolvanenconfig ARCH_SUPPORTS_CFI_CLANG 769cf68fffbSSami Tolvanen bool 770cf68fffbSSami Tolvanen help 771cf68fffbSSami Tolvanen An architecture should select this option if it can support Clang's 772cf68fffbSSami Tolvanen Control-Flow Integrity (CFI) checking. 773cf68fffbSSami Tolvanen 77489245600SSami Tolvanenconfig ARCH_USES_CFI_TRAPS 77589245600SSami Tolvanen bool 77689245600SSami Tolvanen 777cf68fffbSSami Tolvanenconfig CFI_CLANG 778cf68fffbSSami Tolvanen bool "Use Clang's Control Flow Integrity (CFI)" 77989245600SSami Tolvanen depends on ARCH_SUPPORTS_CFI_CLANG 78089245600SSami Tolvanen depends on $(cc-option,-fsanitize=kcfi) 781cf68fffbSSami Tolvanen help 782cf68fffbSSami Tolvanen This option enables Clang’s forward-edge Control Flow Integrity 783cf68fffbSSami Tolvanen (CFI) checking, where the compiler injects a runtime check to each 784cf68fffbSSami Tolvanen indirect function call to ensure the target is a valid function with 785cf68fffbSSami Tolvanen the correct static type. This restricts possible call targets and 786cf68fffbSSami Tolvanen makes it more difficult for an attacker to exploit bugs that allow 787cf68fffbSSami Tolvanen the modification of stored function pointers. More information can be 788cf68fffbSSami Tolvanen found from Clang's documentation: 789cf68fffbSSami Tolvanen 790cf68fffbSSami Tolvanen https://clang.llvm.org/docs/ControlFlowIntegrity.html 791cf68fffbSSami Tolvanen 792cf68fffbSSami Tolvanenconfig CFI_PERMISSIVE 793cf68fffbSSami Tolvanen bool "Use CFI in permissive mode" 794cf68fffbSSami Tolvanen depends on CFI_CLANG 795cf68fffbSSami Tolvanen help 796cf68fffbSSami Tolvanen When selected, Control Flow Integrity (CFI) violations result in a 797cf68fffbSSami Tolvanen warning instead of a kernel panic. This option should only be used 798cf68fffbSSami Tolvanen for finding indirect call type mismatches during development. 799cf68fffbSSami Tolvanen 800cf68fffbSSami Tolvanen If unsure, say N. 801cf68fffbSSami Tolvanen 8020f60a8efSKees Cookconfig HAVE_ARCH_WITHIN_STACK_FRAMES 8030f60a8efSKees Cook bool 8040f60a8efSKees Cook help 8050f60a8efSKees Cook An architecture should select this if it can walk the kernel stack 8060f60a8efSKees Cook frames to determine if an object is part of either the arguments 8070f60a8efSKees Cook or local variables (i.e. that it excludes saved return addresses, 8080f60a8efSKees Cook and similar) by implementing an inline arch_within_stack_frames(), 8090f60a8efSKees Cook which is used by CONFIG_HARDENED_USERCOPY. 8100f60a8efSKees Cook 81124a9c541SFrederic Weisbeckerconfig HAVE_CONTEXT_TRACKING_USER 8122b1d5024SFrederic Weisbecker bool 8132b1d5024SFrederic Weisbecker help 81491d1aa43SFrederic Weisbecker Provide kernel/user boundaries probes necessary for subsystems 81591d1aa43SFrederic Weisbecker that need it, such as userspace RCU extended quiescent state. 816490f561bSFrederic Weisbecker Syscalls need to be wrapped inside user_exit()-user_enter(), either 817490f561bSFrederic Weisbecker optimized behind static key or through the slow path using TIF_NOHZ 818490f561bSFrederic Weisbecker flag. Exceptions handlers must be wrapped as well. Irqs are already 8196f0e6c15SFrederic Weisbecker protected inside ct_irq_enter/ct_irq_exit() but preemption or signal 820490f561bSFrederic Weisbecker handling on irq exit still need to be protected. 821490f561bSFrederic Weisbecker 82224a9c541SFrederic Weisbeckerconfig HAVE_CONTEXT_TRACKING_USER_OFFSTACK 82383c2da2eSFrederic Weisbecker bool 82483c2da2eSFrederic Weisbecker help 82583c2da2eSFrederic Weisbecker Architecture neither relies on exception_enter()/exception_exit() 82683c2da2eSFrederic Weisbecker nor on schedule_user(). Also preempt_schedule_notrace() and 82783c2da2eSFrederic Weisbecker preempt_schedule_irq() can't be called in a preemptible section 82883c2da2eSFrederic Weisbecker while context tracking is CONTEXT_USER. This feature reflects a sane 82983c2da2eSFrederic Weisbecker entry implementation where the following requirements are met on 83083c2da2eSFrederic Weisbecker critical entry code, ie: before user_exit() or after user_enter(): 83183c2da2eSFrederic Weisbecker 83283c2da2eSFrederic Weisbecker - Critical entry code isn't preemptible (or better yet: 83383c2da2eSFrederic Weisbecker not interruptible). 834493c1822SFrederic Weisbecker - No use of RCU read side critical sections, unless ct_nmi_enter() 83583c2da2eSFrederic Weisbecker got called. 83683c2da2eSFrederic Weisbecker - No use of instrumentation, unless instrumentation_begin() got 83783c2da2eSFrederic Weisbecker called. 83883c2da2eSFrederic Weisbecker 839490f561bSFrederic Weisbeckerconfig HAVE_TIF_NOHZ 840490f561bSFrederic Weisbecker bool 841490f561bSFrederic Weisbecker help 842490f561bSFrederic Weisbecker Arch relies on TIF_NOHZ and syscall slow path to implement context 843490f561bSFrederic Weisbecker tracking calls to user_enter()/user_exit(). 8442b1d5024SFrederic Weisbecker 845b952741cSFrederic Weisbeckerconfig HAVE_VIRT_CPU_ACCOUNTING 846b952741cSFrederic Weisbecker bool 847b952741cSFrederic Weisbecker 8482b91ec9fSFrederic Weisbeckerconfig HAVE_VIRT_CPU_ACCOUNTING_IDLE 8492b91ec9fSFrederic Weisbecker bool 8502b91ec9fSFrederic Weisbecker help 8512b91ec9fSFrederic Weisbecker Architecture has its own way to account idle CPU time and therefore 8522b91ec9fSFrederic Weisbecker doesn't implement vtime_account_idle(). 8532b91ec9fSFrederic Weisbecker 85440565b5aSStanislaw Gruszkaconfig ARCH_HAS_SCALED_CPUTIME 85540565b5aSStanislaw Gruszka bool 85640565b5aSStanislaw Gruszka 857554b0004SKevin Hilmanconfig HAVE_VIRT_CPU_ACCOUNTING_GEN 858554b0004SKevin Hilman bool 859554b0004SKevin Hilman default y if 64BIT 860554b0004SKevin Hilman help 861554b0004SKevin Hilman With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. 862554b0004SKevin Hilman Before enabling this option, arch code must be audited 863554b0004SKevin Hilman to ensure there are no races in concurrent read/write of 864554b0004SKevin Hilman cputime_t. For example, reading/writing 64-bit cputime_t on 865554b0004SKevin Hilman some 32-bit arches may require multiple accesses, so proper 866554b0004SKevin Hilman locking is needed to protect against concurrent accesses. 867554b0004SKevin Hilman 868fdf9c356SFrederic Weisbeckerconfig HAVE_IRQ_TIME_ACCOUNTING 869fdf9c356SFrederic Weisbecker bool 870fdf9c356SFrederic Weisbecker help 871fdf9c356SFrederic Weisbecker Archs need to ensure they use a high enough resolution clock to 872fdf9c356SFrederic Weisbecker support irq time accounting and then call enable_sched_clock_irqtime(). 873fdf9c356SFrederic Weisbecker 874c49dd340SKalesh Singhconfig HAVE_MOVE_PUD 875c49dd340SKalesh Singh bool 876c49dd340SKalesh Singh help 877c49dd340SKalesh Singh Architectures that select this are able to move page tables at the 878c49dd340SKalesh Singh PUD level. If there are only 3 page table levels, the move effectively 879c49dd340SKalesh Singh happens at the PGD level. 880c49dd340SKalesh Singh 8812c91bd4aSJoel Fernandes (Google)config HAVE_MOVE_PMD 8822c91bd4aSJoel Fernandes (Google) bool 8832c91bd4aSJoel Fernandes (Google) help 8842c91bd4aSJoel Fernandes (Google) Archs that select this are able to move page tables at the PMD level. 8852c91bd4aSJoel Fernandes (Google) 88615626062SGerald Schaeferconfig HAVE_ARCH_TRANSPARENT_HUGEPAGE 88715626062SGerald Schaefer bool 88815626062SGerald Schaefer 889a00cc7d9SMatthew Wilcoxconfig HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 890a00cc7d9SMatthew Wilcox bool 891a00cc7d9SMatthew Wilcox 8920ddab1d2SToshi Kaniconfig HAVE_ARCH_HUGE_VMAP 8930ddab1d2SToshi Kani bool 8940ddab1d2SToshi Kani 895121e6f32SNicholas Piggin# 896121e6f32SNicholas Piggin# Archs that select this would be capable of PMD-sized vmaps (i.e., 897559089e0SSong Liu# arch_vmap_pmd_supported() returns true). The VM_ALLOW_HUGE_VMAP flag 898559089e0SSong Liu# must be used to enable allocations to use hugepages. 899121e6f32SNicholas Piggin# 900121e6f32SNicholas Pigginconfig HAVE_ARCH_HUGE_VMALLOC 901121e6f32SNicholas Piggin depends on HAVE_ARCH_HUGE_VMAP 902121e6f32SNicholas Piggin bool 903121e6f32SNicholas Piggin 9043876d4a3SAlexandre Ghiticonfig ARCH_WANT_HUGE_PMD_SHARE 9053876d4a3SAlexandre Ghiti bool 9063876d4a3SAlexandre Ghiti 9070f8975ecSPavel Emelyanovconfig HAVE_ARCH_SOFT_DIRTY 9080f8975ecSPavel Emelyanov bool 9090f8975ecSPavel Emelyanov 910786d35d4SDavid Howellsconfig HAVE_MOD_ARCH_SPECIFIC 911786d35d4SDavid Howells bool 912786d35d4SDavid Howells help 913786d35d4SDavid Howells The arch uses struct mod_arch_specific to store data. Many arches 914786d35d4SDavid Howells just need a simple module loader without arch specific data - those 915786d35d4SDavid Howells should not enable this. 916786d35d4SDavid Howells 917786d35d4SDavid Howellsconfig MODULES_USE_ELF_RELA 918786d35d4SDavid Howells bool 919786d35d4SDavid Howells help 920786d35d4SDavid Howells Modules only use ELF RELA relocations. Modules with ELF REL 921786d35d4SDavid Howells relocations will give an error. 922786d35d4SDavid Howells 923786d35d4SDavid Howellsconfig MODULES_USE_ELF_REL 924786d35d4SDavid Howells bool 925786d35d4SDavid Howells help 926786d35d4SDavid Howells Modules only use ELF REL relocations. Modules with ELF RELA 927786d35d4SDavid Howells relocations will give an error. 928786d35d4SDavid Howells 92901dc0386SChristophe Leroyconfig ARCH_WANTS_MODULES_DATA_IN_VMALLOC 93001dc0386SChristophe Leroy bool 93101dc0386SChristophe Leroy help 93201dc0386SChristophe Leroy For architectures like powerpc/32 which have constraints on module 93301dc0386SChristophe Leroy allocation and need to allocate module data outside of module area. 93401dc0386SChristophe Leroy 935cc1f0274SFrederic Weisbeckerconfig HAVE_IRQ_EXIT_ON_IRQ_STACK 936cc1f0274SFrederic Weisbecker bool 937cc1f0274SFrederic Weisbecker help 938cc1f0274SFrederic Weisbecker Architecture doesn't only execute the irq handler on the irq stack 939cc1f0274SFrederic Weisbecker but also irq_exit(). This way we can process softirqs on this irq 940cc1f0274SFrederic Weisbecker stack instead of switching to a new one when we call __do_softirq() 941cc1f0274SFrederic Weisbecker in the end of an hardirq. 942cc1f0274SFrederic Weisbecker This spares a stack switch and improves cache usage on softirq 943cc1f0274SFrederic Weisbecker processing. 944cc1f0274SFrederic Weisbecker 945cd1a41ceSThomas Gleixnerconfig HAVE_SOFTIRQ_ON_OWN_STACK 946cd1a41ceSThomas Gleixner bool 947cd1a41ceSThomas Gleixner help 948cd1a41ceSThomas Gleixner Architecture provides a function to run __do_softirq() on a 949c226bc3cSColin Ian King separate stack. 950cd1a41ceSThomas Gleixner 9518cbb2b50SSebastian Andrzej Siewiorconfig SOFTIRQ_ON_OWN_STACK 9528cbb2b50SSebastian Andrzej Siewior def_bool HAVE_SOFTIRQ_ON_OWN_STACK && !PREEMPT_RT 9538cbb2b50SSebastian Andrzej Siewior 95412700c17SArnd Bergmannconfig ALTERNATE_USER_ADDRESS_SPACE 95512700c17SArnd Bergmann bool 95612700c17SArnd Bergmann help 95712700c17SArnd Bergmann Architectures set this when the CPU uses separate address 95812700c17SArnd Bergmann spaces for kernel and user space pointers. In this case, the 95912700c17SArnd Bergmann access_ok() check on a __user pointer is skipped. 96012700c17SArnd Bergmann 961235a8f02SKirill A. Shutemovconfig PGTABLE_LEVELS 962235a8f02SKirill A. Shutemov int 963235a8f02SKirill A. Shutemov default 2 964235a8f02SKirill A. Shutemov 9652b68f6caSKees Cookconfig ARCH_HAS_ELF_RANDOMIZE 9662b68f6caSKees Cook bool 9672b68f6caSKees Cook help 9682b68f6caSKees Cook An architecture supports choosing randomized locations for 9692b68f6caSKees Cook stack, mmap, brk, and ET_DYN. Defined functions: 9702b68f6caSKees Cook - arch_mmap_rnd() 971204db6edSKees Cook - arch_randomize_brk() 9722b68f6caSKees Cook 973d07e2259SDaniel Cashmanconfig HAVE_ARCH_MMAP_RND_BITS 974d07e2259SDaniel Cashman bool 975d07e2259SDaniel Cashman help 976d07e2259SDaniel Cashman An arch should select this symbol if it supports setting a variable 977d07e2259SDaniel Cashman number of bits for use in establishing the base address for mmap 978d07e2259SDaniel Cashman allocations, has MMU enabled and provides values for both: 979d07e2259SDaniel Cashman - ARCH_MMAP_RND_BITS_MIN 980d07e2259SDaniel Cashman - ARCH_MMAP_RND_BITS_MAX 981d07e2259SDaniel Cashman 9825f56a5dfSJiri Slabyconfig HAVE_EXIT_THREAD 9835f56a5dfSJiri Slaby bool 9845f56a5dfSJiri Slaby help 9855f56a5dfSJiri Slaby An architecture implements exit_thread. 9865f56a5dfSJiri Slaby 987d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 988d07e2259SDaniel Cashman int 989d07e2259SDaniel Cashman 990d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 991d07e2259SDaniel Cashman int 992d07e2259SDaniel Cashman 993d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS_DEFAULT 994d07e2259SDaniel Cashman int 995d07e2259SDaniel Cashman 996d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS 997d07e2259SDaniel Cashman int "Number of bits to use for ASLR of mmap base address" if EXPERT 998d07e2259SDaniel Cashman range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX 999d07e2259SDaniel Cashman default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT 1000d07e2259SDaniel Cashman default ARCH_MMAP_RND_BITS_MIN 1001d07e2259SDaniel Cashman depends on HAVE_ARCH_MMAP_RND_BITS 1002d07e2259SDaniel Cashman help 1003d07e2259SDaniel Cashman This value can be used to select the number of bits to use to 1004d07e2259SDaniel Cashman determine the random offset to the base address of vma regions 1005d07e2259SDaniel Cashman resulting from mmap allocations. This value will be bounded 1006d07e2259SDaniel Cashman by the architecture's minimum and maximum supported values. 1007d07e2259SDaniel Cashman 1008d07e2259SDaniel Cashman This value can be changed after boot using the 1009d07e2259SDaniel Cashman /proc/sys/vm/mmap_rnd_bits tunable 1010d07e2259SDaniel Cashman 1011d07e2259SDaniel Cashmanconfig HAVE_ARCH_MMAP_RND_COMPAT_BITS 1012d07e2259SDaniel Cashman bool 1013d07e2259SDaniel Cashman help 1014d07e2259SDaniel Cashman An arch should select this symbol if it supports running applications 1015d07e2259SDaniel Cashman in compatibility mode, supports setting a variable number of bits for 1016d07e2259SDaniel Cashman use in establishing the base address for mmap allocations, has MMU 1017d07e2259SDaniel Cashman enabled and provides values for both: 1018d07e2259SDaniel Cashman - ARCH_MMAP_RND_COMPAT_BITS_MIN 1019d07e2259SDaniel Cashman - ARCH_MMAP_RND_COMPAT_BITS_MAX 1020d07e2259SDaniel Cashman 1021d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 1022d07e2259SDaniel Cashman int 1023d07e2259SDaniel Cashman 1024d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 1025d07e2259SDaniel Cashman int 1026d07e2259SDaniel Cashman 1027d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 1028d07e2259SDaniel Cashman int 1029d07e2259SDaniel Cashman 1030d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS 1031d07e2259SDaniel Cashman int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT 1032d07e2259SDaniel Cashman range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX 1033d07e2259SDaniel Cashman default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 1034d07e2259SDaniel Cashman default ARCH_MMAP_RND_COMPAT_BITS_MIN 1035d07e2259SDaniel Cashman depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS 1036d07e2259SDaniel Cashman help 1037d07e2259SDaniel Cashman This value can be used to select the number of bits to use to 1038d07e2259SDaniel Cashman determine the random offset to the base address of vma regions 1039d07e2259SDaniel Cashman resulting from mmap allocations for compatible applications This 1040d07e2259SDaniel Cashman value will be bounded by the architecture's minimum and maximum 1041d07e2259SDaniel Cashman supported values. 1042d07e2259SDaniel Cashman 1043d07e2259SDaniel Cashman This value can be changed after boot using the 1044d07e2259SDaniel Cashman /proc/sys/vm/mmap_rnd_compat_bits tunable 1045d07e2259SDaniel Cashman 10461b028f78SDmitry Safonovconfig HAVE_ARCH_COMPAT_MMAP_BASES 10471b028f78SDmitry Safonov bool 10481b028f78SDmitry Safonov help 10491b028f78SDmitry Safonov This allows 64bit applications to invoke 32-bit mmap() syscall 10501b028f78SDmitry Safonov and vice-versa 32-bit applications to call 64-bit mmap(). 10511b028f78SDmitry Safonov Required for applications doing different bitness syscalls. 10521b028f78SDmitry Safonov 10531f0e290cSGuenter Roeckconfig PAGE_SIZE_LESS_THAN_64KB 10541f0e290cSGuenter Roeck def_bool y 10551f0e290cSGuenter Roeck depends on !ARM64_64K_PAGES 10561f0e290cSGuenter Roeck depends on !IA64_PAGE_SIZE_64KB 10571f0e290cSGuenter Roeck depends on !PAGE_SIZE_64KB 10581f0e290cSGuenter Roeck depends on !PARISC_PAGE_SIZE_64KB 1059e4bbd20dSNathan Chancellor depends on PAGE_SIZE_LESS_THAN_256KB 1060e4bbd20dSNathan Chancellor 1061e4bbd20dSNathan Chancellorconfig PAGE_SIZE_LESS_THAN_256KB 1062e4bbd20dSNathan Chancellor def_bool y 10631f0e290cSGuenter Roeck depends on !PAGE_SIZE_256KB 10641f0e290cSGuenter Roeck 106567f3977fSAlexandre Ghiti# This allows to use a set of generic functions to determine mmap base 106667f3977fSAlexandre Ghiti# address by giving priority to top-down scheme only if the process 106767f3977fSAlexandre Ghiti# is not in legacy mode (compat task, unlimited stack size or 106867f3977fSAlexandre Ghiti# sysctl_legacy_va_layout). 106967f3977fSAlexandre Ghiti# Architecture that selects this option can provide its own version of: 107067f3977fSAlexandre Ghiti# - STACK_RND_MASK 107167f3977fSAlexandre Ghiticonfig ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 107267f3977fSAlexandre Ghiti bool 107367f3977fSAlexandre Ghiti depends on MMU 1074e7142bf5SAlexandre Ghiti select ARCH_HAS_ELF_RANDOMIZE 107567f3977fSAlexandre Ghiti 107603f16cd0SJosh Poimboeufconfig HAVE_OBJTOOL 107703f16cd0SJosh Poimboeuf bool 107803f16cd0SJosh Poimboeuf 10794ab7674fSJosh Poimboeufconfig HAVE_JUMP_LABEL_HACK 10804ab7674fSJosh Poimboeuf bool 10814ab7674fSJosh Poimboeuf 108222102f45SJosh Poimboeufconfig HAVE_NOINSTR_HACK 108322102f45SJosh Poimboeuf bool 108422102f45SJosh Poimboeuf 1085489e355bSJosh Poimboeufconfig HAVE_NOINSTR_VALIDATION 1086489e355bSJosh Poimboeuf bool 1087489e355bSJosh Poimboeuf 10885f3da8c0SJosh Poimboeufconfig HAVE_UACCESS_VALIDATION 10895f3da8c0SJosh Poimboeuf bool 10905f3da8c0SJosh Poimboeuf select OBJTOOL 10915f3da8c0SJosh Poimboeuf 1092b9ab5ebbSJosh Poimboeufconfig HAVE_STACK_VALIDATION 1093b9ab5ebbSJosh Poimboeuf bool 1094b9ab5ebbSJosh Poimboeuf help 109503f16cd0SJosh Poimboeuf Architecture supports objtool compile-time frame pointer rule 109603f16cd0SJosh Poimboeuf validation. 1097b9ab5ebbSJosh Poimboeuf 1098af085d90SJosh Poimboeufconfig HAVE_RELIABLE_STACKTRACE 1099af085d90SJosh Poimboeuf bool 1100af085d90SJosh Poimboeuf help 1101140d7e88SMiroslav Benes Architecture has either save_stack_trace_tsk_reliable() or 1102140d7e88SMiroslav Benes arch_stack_walk_reliable() function which only returns a stack trace 1103140d7e88SMiroslav Benes if it can guarantee the trace is reliable. 1104af085d90SJosh Poimboeuf 1105468a9428SGeorge Spelvinconfig HAVE_ARCH_HASH 1106468a9428SGeorge Spelvin bool 1107468a9428SGeorge Spelvin default n 1108468a9428SGeorge Spelvin help 1109468a9428SGeorge Spelvin If this is set, the architecture provides an <asm/hash.h> 1110468a9428SGeorge Spelvin file which provides platform-specific implementations of some 1111468a9428SGeorge Spelvin functions in <linux/hash.h> or fs/namei.c. 1112468a9428SGeorge Spelvin 1113666047feSFinn Thainconfig HAVE_ARCH_NVRAM_OPS 1114666047feSFinn Thain bool 1115666047feSFinn Thain 11163a495511SWilliam Breathitt Grayconfig ISA_BUS_API 11173a495511SWilliam Breathitt Gray def_bool ISA 11183a495511SWilliam Breathitt Gray 1119d2125043SAl Viro# 1120d2125043SAl Viro# ABI hall of shame 1121d2125043SAl Viro# 1122d2125043SAl Viroconfig CLONE_BACKWARDS 1123d2125043SAl Viro bool 1124d2125043SAl Viro help 1125d2125043SAl Viro Architecture has tls passed as the 4th argument of clone(2), 1126d2125043SAl Viro not the 5th one. 1127d2125043SAl Viro 1128d2125043SAl Viroconfig CLONE_BACKWARDS2 1129d2125043SAl Viro bool 1130d2125043SAl Viro help 1131d2125043SAl Viro Architecture has the first two arguments of clone(2) swapped. 1132d2125043SAl Viro 1133dfa9771aSMichal Simekconfig CLONE_BACKWARDS3 1134dfa9771aSMichal Simek bool 1135dfa9771aSMichal Simek help 1136dfa9771aSMichal Simek Architecture has tls passed as the 3rd argument of clone(2), 1137dfa9771aSMichal Simek not the 5th one. 1138dfa9771aSMichal Simek 1139eaca6eaeSAl Viroconfig ODD_RT_SIGACTION 1140eaca6eaeSAl Viro bool 1141eaca6eaeSAl Viro help 1142eaca6eaeSAl Viro Architecture has unusual rt_sigaction(2) arguments 1143eaca6eaeSAl Viro 11440a0e8cdfSAl Viroconfig OLD_SIGSUSPEND 11450a0e8cdfSAl Viro bool 11460a0e8cdfSAl Viro help 11470a0e8cdfSAl Viro Architecture has old sigsuspend(2) syscall, of one-argument variety 11480a0e8cdfSAl Viro 11490a0e8cdfSAl Viroconfig OLD_SIGSUSPEND3 11500a0e8cdfSAl Viro bool 11510a0e8cdfSAl Viro help 11520a0e8cdfSAl Viro Even weirder antique ABI - three-argument sigsuspend(2) 11530a0e8cdfSAl Viro 1154495dfbf7SAl Viroconfig OLD_SIGACTION 1155495dfbf7SAl Viro bool 1156495dfbf7SAl Viro help 1157495dfbf7SAl Viro Architecture has old sigaction(2) syscall. Nope, not the same 1158495dfbf7SAl Viro as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), 1159495dfbf7SAl Viro but fairly different variant of sigaction(2), thanks to OSF/1 1160495dfbf7SAl Viro compatibility... 1161495dfbf7SAl Viro 1162495dfbf7SAl Viroconfig COMPAT_OLD_SIGACTION 1163495dfbf7SAl Viro bool 1164495dfbf7SAl Viro 116517435e5fSDeepa Dinamaniconfig COMPAT_32BIT_TIME 1166942437c9SArnd Bergmann bool "Provide system calls for 32-bit time_t" 1167942437c9SArnd Bergmann default !64BIT || COMPAT 116817435e5fSDeepa Dinamani help 116917435e5fSDeepa Dinamani This enables 32 bit time_t support in addition to 64 bit time_t support. 117017435e5fSDeepa Dinamani This is relevant on all 32-bit architectures, and 64-bit architectures 117117435e5fSDeepa Dinamani as part of compat syscall handling. 117217435e5fSDeepa Dinamani 117387a4c375SChristoph Hellwigconfig ARCH_NO_PREEMPT 117487a4c375SChristoph Hellwig bool 117587a4c375SChristoph Hellwig 1176cb2c7d1aSMickaël Salaünconfig ARCH_EPHEMERAL_INODES 1177cb2c7d1aSMickaël Salaün def_bool n 1178cb2c7d1aSMickaël Salaün help 1179cb2c7d1aSMickaël Salaün An arch should select this symbol if it doesn't keep track of inode 1180cb2c7d1aSMickaël Salaün instances on its own, but instead relies on something else (e.g. the 1181cb2c7d1aSMickaël Salaün host kernel for an UML kernel). 1182cb2c7d1aSMickaël Salaün 1183a50a3f4bSThomas Gleixnerconfig ARCH_SUPPORTS_RT 1184a50a3f4bSThomas Gleixner bool 1185a50a3f4bSThomas Gleixner 1186fff7fb0bSZhaoxiu Zengconfig CPU_NO_EFFICIENT_FFS 1187fff7fb0bSZhaoxiu Zeng def_bool n 1188fff7fb0bSZhaoxiu Zeng 1189ba14a194SAndy Lutomirskiconfig HAVE_ARCH_VMAP_STACK 1190ba14a194SAndy Lutomirski def_bool n 1191ba14a194SAndy Lutomirski help 1192ba14a194SAndy Lutomirski An arch should select this symbol if it can support kernel stacks 1193ba14a194SAndy Lutomirski in vmalloc space. This means: 1194ba14a194SAndy Lutomirski 1195ba14a194SAndy Lutomirski - vmalloc space must be large enough to hold many kernel stacks. 1196ba14a194SAndy Lutomirski This may rule out many 32-bit architectures. 1197ba14a194SAndy Lutomirski 1198ba14a194SAndy Lutomirski - Stacks in vmalloc space need to work reliably. For example, if 1199ba14a194SAndy Lutomirski vmap page tables are created on demand, either this mechanism 1200ba14a194SAndy Lutomirski needs to work while the stack points to a virtual address with 1201ba14a194SAndy Lutomirski unpopulated page tables or arch code (switch_to() and switch_mm(), 1202ba14a194SAndy Lutomirski most likely) needs to ensure that the stack's page table entries 1203ba14a194SAndy Lutomirski are populated before running on a possibly unpopulated stack. 1204ba14a194SAndy Lutomirski 1205ba14a194SAndy Lutomirski - If the stack overflows into a guard page, something reasonable 1206ba14a194SAndy Lutomirski should happen. The definition of "reasonable" is flexible, but 1207ba14a194SAndy Lutomirski instantly rebooting without logging anything would be unfriendly. 1208ba14a194SAndy Lutomirski 1209ba14a194SAndy Lutomirskiconfig VMAP_STACK 1210ba14a194SAndy Lutomirski default y 1211ba14a194SAndy Lutomirski bool "Use a virtually-mapped stack" 1212eafb149eSDaniel Axtens depends on HAVE_ARCH_VMAP_STACK 121338dd767dSAndrey Konovalov depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC 1214a7f7f624SMasahiro Yamada help 1215ba14a194SAndy Lutomirski Enable this if you want the use virtually-mapped kernel stacks 1216ba14a194SAndy Lutomirski with guard pages. This causes kernel stack overflows to be 1217ba14a194SAndy Lutomirski caught immediately rather than causing difficult-to-diagnose 1218ba14a194SAndy Lutomirski corruption. 1219ba14a194SAndy Lutomirski 122038dd767dSAndrey Konovalov To use this with software KASAN modes, the architecture must support 122138dd767dSAndrey Konovalov backing virtual mappings with real shadow memory, and KASAN_VMALLOC 122238dd767dSAndrey Konovalov must be enabled. 1223ba14a194SAndy Lutomirski 122439218ff4SKees Cookconfig HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 122539218ff4SKees Cook def_bool n 122639218ff4SKees Cook help 122739218ff4SKees Cook An arch should select this symbol if it can support kernel stack 122839218ff4SKees Cook offset randomization with calls to add_random_kstack_offset() 122939218ff4SKees Cook during syscall entry and choose_random_kstack_offset() during 123039218ff4SKees Cook syscall exit. Careful removal of -fstack-protector-strong and 123139218ff4SKees Cook -fstack-protector should also be applied to the entry code and 123239218ff4SKees Cook closely examined, as the artificial stack bump looks like an array 123339218ff4SKees Cook to the compiler, so it will attempt to add canary checks regardless 123439218ff4SKees Cook of the static branch state. 123539218ff4SKees Cook 12368cb37a59SMarco Elverconfig RANDOMIZE_KSTACK_OFFSET 12378cb37a59SMarco Elver bool "Support for randomizing kernel stack offset on syscall entry" if EXPERT 12388cb37a59SMarco Elver default y 123939218ff4SKees Cook depends on HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 1240efa90c11SMarco Elver depends on INIT_STACK_NONE || !CC_IS_CLANG || CLANG_VERSION >= 140000 124139218ff4SKees Cook help 124239218ff4SKees Cook The kernel stack offset can be randomized (after pt_regs) by 124339218ff4SKees Cook roughly 5 bits of entropy, frustrating memory corruption 124439218ff4SKees Cook attacks that depend on stack address determinism or 12458cb37a59SMarco Elver cross-syscall address exposures. 12468cb37a59SMarco Elver 12478cb37a59SMarco Elver The feature is controlled via the "randomize_kstack_offset=on/off" 12488cb37a59SMarco Elver kernel boot param, and if turned off has zero overhead due to its use 12498cb37a59SMarco Elver of static branches (see JUMP_LABEL). 12508cb37a59SMarco Elver 12518cb37a59SMarco Elver If unsure, say Y. 12528cb37a59SMarco Elver 12538cb37a59SMarco Elverconfig RANDOMIZE_KSTACK_OFFSET_DEFAULT 12548cb37a59SMarco Elver bool "Default state of kernel stack offset randomization" 12558cb37a59SMarco Elver depends on RANDOMIZE_KSTACK_OFFSET 12568cb37a59SMarco Elver help 12578cb37a59SMarco Elver Kernel stack offset randomization is controlled by kernel boot param 12588cb37a59SMarco Elver "randomize_kstack_offset=on/off", and this config chooses the default 12598cb37a59SMarco Elver boot state. 126039218ff4SKees Cook 1261ad21fc4fSLaura Abbottconfig ARCH_OPTIONAL_KERNEL_RWX 1262ad21fc4fSLaura Abbott def_bool n 1263ad21fc4fSLaura Abbott 1264ad21fc4fSLaura Abbottconfig ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1265ad21fc4fSLaura Abbott def_bool n 1266ad21fc4fSLaura Abbott 1267ad21fc4fSLaura Abbottconfig ARCH_HAS_STRICT_KERNEL_RWX 1268ad21fc4fSLaura Abbott def_bool n 1269ad21fc4fSLaura Abbott 12700f5bf6d0SLaura Abbottconfig STRICT_KERNEL_RWX 1271ad21fc4fSLaura Abbott bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX 1272ad21fc4fSLaura Abbott depends on ARCH_HAS_STRICT_KERNEL_RWX 1273ad21fc4fSLaura Abbott default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1274ad21fc4fSLaura Abbott help 1275ad21fc4fSLaura Abbott If this is set, kernel text and rodata memory will be made read-only, 1276ad21fc4fSLaura Abbott and non-text memory will be made non-executable. This provides 1277ad21fc4fSLaura Abbott protection against certain security exploits (e.g. executing the heap 1278ad21fc4fSLaura Abbott or modifying text) 1279ad21fc4fSLaura Abbott 1280ad21fc4fSLaura Abbott These features are considered standard security practice these days. 1281ad21fc4fSLaura Abbott You should say Y here in almost all cases. 1282ad21fc4fSLaura Abbott 1283ad21fc4fSLaura Abbottconfig ARCH_HAS_STRICT_MODULE_RWX 1284ad21fc4fSLaura Abbott def_bool n 1285ad21fc4fSLaura Abbott 12860f5bf6d0SLaura Abbottconfig STRICT_MODULE_RWX 1287ad21fc4fSLaura Abbott bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX 1288ad21fc4fSLaura Abbott depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES 1289ad21fc4fSLaura Abbott default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 1290ad21fc4fSLaura Abbott help 1291ad21fc4fSLaura Abbott If this is set, module text and rodata memory will be made read-only, 1292ad21fc4fSLaura Abbott and non-text memory will be made non-executable. This provides 1293ad21fc4fSLaura Abbott protection against certain security exploits (e.g. writing to text) 1294ad21fc4fSLaura Abbott 1295ea8c64acSChristoph Hellwig# select if the architecture provides an asm/dma-direct.h header 1296ea8c64acSChristoph Hellwigconfig ARCH_HAS_PHYS_TO_DMA 1297ea8c64acSChristoph Hellwig bool 1298ea8c64acSChristoph Hellwig 129904f264d3SPaul Burtonconfig HAVE_ARCH_COMPILER_H 130004f264d3SPaul Burton bool 130104f264d3SPaul Burton help 130204f264d3SPaul Burton An architecture can select this if it provides an 130304f264d3SPaul Burton asm/compiler.h header that should be included after 130404f264d3SPaul Burton linux/compiler-*.h in order to override macro definitions that those 130504f264d3SPaul Burton headers generally provide. 130604f264d3SPaul Burton 1307271ca788SArd Biesheuvelconfig HAVE_ARCH_PREL32_RELOCATIONS 1308271ca788SArd Biesheuvel bool 1309271ca788SArd Biesheuvel help 1310271ca788SArd Biesheuvel May be selected by an architecture if it supports place-relative 1311271ca788SArd Biesheuvel 32-bit relocations, both in the toolchain and in the module loader, 1312271ca788SArd Biesheuvel in which case relative references can be used in special sections 1313271ca788SArd Biesheuvel for PCI fixup, initcalls etc which are only half the size on 64 bit 1314271ca788SArd Biesheuvel architectures, and don't require runtime relocation on relocatable 1315271ca788SArd Biesheuvel kernels. 1316271ca788SArd Biesheuvel 1317ce9084baSArd Biesheuvelconfig ARCH_USE_MEMREMAP_PROT 1318ce9084baSArd Biesheuvel bool 1319ce9084baSArd Biesheuvel 1320fb346fd9SWaiman Longconfig LOCK_EVENT_COUNTS 1321fb346fd9SWaiman Long bool "Locking event counts collection" 1322fb346fd9SWaiman Long depends on DEBUG_FS 1323a7f7f624SMasahiro Yamada help 1324fb346fd9SWaiman Long Enable light-weight counting of various locking related events 1325fb346fd9SWaiman Long in the system with minimal performance impact. This reduces 1326fb346fd9SWaiman Long the chance of application behavior change because of timing 1327fb346fd9SWaiman Long differences. The counts are reported via debugfs. 1328fb346fd9SWaiman Long 13295cf896fbSPeter Collingbourne# Select if the architecture has support for applying RELR relocations. 13305cf896fbSPeter Collingbourneconfig ARCH_HAS_RELR 13315cf896fbSPeter Collingbourne bool 13325cf896fbSPeter Collingbourne 13335cf896fbSPeter Collingbourneconfig RELR 13345cf896fbSPeter Collingbourne bool "Use RELR relocation packing" 13355cf896fbSPeter Collingbourne depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR 13365cf896fbSPeter Collingbourne default y 13375cf896fbSPeter Collingbourne help 13385cf896fbSPeter Collingbourne Store the kernel's dynamic relocations in the RELR relocation packing 13395cf896fbSPeter Collingbourne format. Requires a compatible linker (LLD supports this feature), as 13405cf896fbSPeter Collingbourne well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy 13415cf896fbSPeter Collingbourne are compatible). 13425cf896fbSPeter Collingbourne 13430c9c1d56SThiago Jung Bauermannconfig ARCH_HAS_MEM_ENCRYPT 13440c9c1d56SThiago Jung Bauermann bool 13450c9c1d56SThiago Jung Bauermann 134646b49b12STom Lendackyconfig ARCH_HAS_CC_PLATFORM 134746b49b12STom Lendacky bool 134846b49b12STom Lendacky 13490e242208SHassan Naveedconfig HAVE_SPARSE_SYSCALL_NR 13500e242208SHassan Naveed bool 13510e242208SHassan Naveed help 13520e242208SHassan Naveed An architecture should select this if its syscall numbering is sparse 13530e242208SHassan Naveed to save space. For example, MIPS architecture has a syscall array with 13540e242208SHassan Naveed entries at 4000, 5000 and 6000 locations. This option turns on syscall 13550e242208SHassan Naveed related optimizations for a given architecture. 13560e242208SHassan Naveed 1357d60d7de3SSven Schnelleconfig ARCH_HAS_VDSO_DATA 1358d60d7de3SSven Schnelle bool 1359d60d7de3SSven Schnelle 1360115284d8SJosh Poimboeufconfig HAVE_STATIC_CALL 1361115284d8SJosh Poimboeuf bool 1362115284d8SJosh Poimboeuf 13639183c3f9SJosh Poimboeufconfig HAVE_STATIC_CALL_INLINE 13649183c3f9SJosh Poimboeuf bool 13659183c3f9SJosh Poimboeuf depends on HAVE_STATIC_CALL 136603f16cd0SJosh Poimboeuf select OBJTOOL 13679183c3f9SJosh Poimboeuf 13686ef869e0SMichal Hockoconfig HAVE_PREEMPT_DYNAMIC 13696ef869e0SMichal Hocko bool 137099cf983cSMark Rutland 137199cf983cSMark Rutlandconfig HAVE_PREEMPT_DYNAMIC_CALL 137299cf983cSMark Rutland bool 13736ef869e0SMichal Hocko depends on HAVE_STATIC_CALL 137499cf983cSMark Rutland select HAVE_PREEMPT_DYNAMIC 13756ef869e0SMichal Hocko help 137699cf983cSMark Rutland An architecture should select this if it can handle the preemption 137799cf983cSMark Rutland model being selected at boot time using static calls. 137899cf983cSMark Rutland 137999cf983cSMark Rutland Where an architecture selects HAVE_STATIC_CALL_INLINE, any call to a 138099cf983cSMark Rutland preemption function will be patched directly. 138199cf983cSMark Rutland 138299cf983cSMark Rutland Where an architecture does not select HAVE_STATIC_CALL_INLINE, any 138399cf983cSMark Rutland call to a preemption function will go through a trampoline, and the 138499cf983cSMark Rutland trampoline will be patched. 138599cf983cSMark Rutland 138699cf983cSMark Rutland It is strongly advised to support inline static call to avoid any 138799cf983cSMark Rutland overhead. 138899cf983cSMark Rutland 138999cf983cSMark Rutlandconfig HAVE_PREEMPT_DYNAMIC_KEY 139099cf983cSMark Rutland bool 1391a0a12c3eSNick Desaulniers depends on HAVE_ARCH_JUMP_LABEL 139299cf983cSMark Rutland select HAVE_PREEMPT_DYNAMIC 139399cf983cSMark Rutland help 139499cf983cSMark Rutland An architecture should select this if it can handle the preemption 139599cf983cSMark Rutland model being selected at boot time using static keys. 139699cf983cSMark Rutland 139799cf983cSMark Rutland Each preemption function will be given an early return based on a 139899cf983cSMark Rutland static key. This should have slightly lower overhead than non-inline 139999cf983cSMark Rutland static calls, as this effectively inlines each trampoline into the 140099cf983cSMark Rutland start of its callee. This may avoid redundant work, and may 140199cf983cSMark Rutland integrate better with CFI schemes. 140299cf983cSMark Rutland 140399cf983cSMark Rutland This will have greater overhead than using inline static calls as 140499cf983cSMark Rutland the call to the preemption function cannot be entirely elided. 14056ef869e0SMichal Hocko 140659612b24SNathan Chancellorconfig ARCH_WANT_LD_ORPHAN_WARN 140759612b24SNathan Chancellor bool 140859612b24SNathan Chancellor help 140959612b24SNathan Chancellor An arch should select this symbol once all linker sections are explicitly 141059612b24SNathan Chancellor included, size-asserted, or discarded in the linker scripts. This is 141159612b24SNathan Chancellor important because we never want expected sections to be placed heuristically 141259612b24SNathan Chancellor by the linker, since the locations of such sections can change between linker 141359612b24SNathan Chancellor versions. 141459612b24SNathan Chancellor 14154f5b0c17SMike Rapoportconfig HAVE_ARCH_PFN_VALID 14164f5b0c17SMike Rapoport bool 14174f5b0c17SMike Rapoport 14185d6ad668SMike Rapoportconfig ARCH_SUPPORTS_DEBUG_PAGEALLOC 14195d6ad668SMike Rapoport bool 14205d6ad668SMike Rapoport 1421df4e817bSPasha Tatashinconfig ARCH_SUPPORTS_PAGE_TABLE_CHECK 1422df4e817bSPasha Tatashin bool 1423df4e817bSPasha Tatashin 14242ca408d9SBrian Gerstconfig ARCH_SPLIT_ARG64 14252ca408d9SBrian Gerst bool 14262ca408d9SBrian Gerst help 14272ca408d9SBrian Gerst If a 32-bit architecture requires 64-bit arguments to be split into 14282ca408d9SBrian Gerst pairs of 32-bit arguments, select this option. 14292ca408d9SBrian Gerst 14307facdc42SAl Viroconfig ARCH_HAS_ELFCORE_COMPAT 14317facdc42SAl Viro bool 14327facdc42SAl Viro 143358e106e7SBalbir Singhconfig ARCH_HAS_PARANOID_L1D_FLUSH 143458e106e7SBalbir Singh bool 143558e106e7SBalbir Singh 1436d593d64fSPrasad Sodagudiconfig ARCH_HAVE_TRACE_MMIO_ACCESS 1437d593d64fSPrasad Sodagudi bool 1438d593d64fSPrasad Sodagudi 14391bdda24cSThomas Gleixnerconfig DYNAMIC_SIGFRAME 14401bdda24cSThomas Gleixner bool 14411bdda24cSThomas Gleixner 144250468e43SJarkko Sakkinen# Select, if arch has a named attribute group bound to NUMA device nodes. 144350468e43SJarkko Sakkinenconfig HAVE_ARCH_NODE_DEV_GROUP 144450468e43SJarkko Sakkinen bool 144550468e43SJarkko Sakkinen 1446eed9a328SYu Zhaoconfig ARCH_HAS_NONLEAF_PMD_YOUNG 1447eed9a328SYu Zhao bool 1448eed9a328SYu Zhao help 1449eed9a328SYu Zhao Architectures that select this option are capable of setting the 1450eed9a328SYu Zhao accessed bit in non-leaf PMD entries when using them as part of linear 1451eed9a328SYu Zhao address translations. Page table walkers that clear the accessed bit 1452eed9a328SYu Zhao may use this capability to reduce their search space. 1453eed9a328SYu Zhao 14542521f2c2SPeter Oberparleitersource "kernel/gcov/Kconfig" 145545332b1bSMasahiro Yamada 145645332b1bSMasahiro Yamadasource "scripts/gcc-plugins/Kconfig" 1457fa1b5d09SLinus Torvalds 1458d49a0626SPeter Zijlstraconfig FUNCTION_ALIGNMENT_4B 1459d49a0626SPeter Zijlstra bool 1460d49a0626SPeter Zijlstra 1461d49a0626SPeter Zijlstraconfig FUNCTION_ALIGNMENT_8B 1462d49a0626SPeter Zijlstra bool 1463d49a0626SPeter Zijlstra 1464d49a0626SPeter Zijlstraconfig FUNCTION_ALIGNMENT_16B 1465d49a0626SPeter Zijlstra bool 1466d49a0626SPeter Zijlstra 1467d49a0626SPeter Zijlstraconfig FUNCTION_ALIGNMENT_32B 1468d49a0626SPeter Zijlstra bool 1469d49a0626SPeter Zijlstra 1470d49a0626SPeter Zijlstraconfig FUNCTION_ALIGNMENT_64B 1471d49a0626SPeter Zijlstra bool 1472d49a0626SPeter Zijlstra 1473d49a0626SPeter Zijlstraconfig FUNCTION_ALIGNMENT 1474d49a0626SPeter Zijlstra int 1475d49a0626SPeter Zijlstra default 64 if FUNCTION_ALIGNMENT_64B 1476d49a0626SPeter Zijlstra default 32 if FUNCTION_ALIGNMENT_32B 1477d49a0626SPeter Zijlstra default 16 if FUNCTION_ALIGNMENT_16B 1478d49a0626SPeter Zijlstra default 8 if FUNCTION_ALIGNMENT_8B 1479d49a0626SPeter Zijlstra default 4 if FUNCTION_ALIGNMENT_4B 1480d49a0626SPeter Zijlstra default 0 1481d49a0626SPeter Zijlstra 148222471e13SRandy Dunlapendmenu 1483