xref: /openbmc/linux/arch/Kconfig (revision 349fde59)
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
14da32b581SCatalin Marinasconfig ARCH_HAS_SUBPAGE_FAULTS
15da32b581SCatalin Marinas	bool
16da32b581SCatalin Marinas	help
17da32b581SCatalin Marinas	  Select if the architecture can check permissions at sub-page
18da32b581SCatalin Marinas	  granularity (e.g. arm64 MTE). The probe_user_*() functions
19da32b581SCatalin Marinas	  must be implemented.
20da32b581SCatalin Marinas
2105736e4aSThomas Gleixnerconfig HOTPLUG_SMT
2205736e4aSThomas Gleixner	bool
2305736e4aSThomas Gleixner
246f062123SThomas Gleixner# Selected by HOTPLUG_CORE_SYNC_DEAD or HOTPLUG_CORE_SYNC_FULL
256f062123SThomas Gleixnerconfig HOTPLUG_CORE_SYNC
266f062123SThomas Gleixner	bool
276f062123SThomas Gleixner
286f062123SThomas Gleixner# Basic CPU dead synchronization selected by architecture
296f062123SThomas Gleixnerconfig HOTPLUG_CORE_SYNC_DEAD
306f062123SThomas Gleixner	bool
316f062123SThomas Gleixner	select HOTPLUG_CORE_SYNC
326f062123SThomas Gleixner
336f062123SThomas Gleixner# Full CPU synchronization with alive state selected by architecture
346f062123SThomas Gleixnerconfig HOTPLUG_CORE_SYNC_FULL
356f062123SThomas Gleixner	bool
366f062123SThomas Gleixner	select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
376f062123SThomas Gleixner	select HOTPLUG_CORE_SYNC
386f062123SThomas Gleixner
39a631be92SThomas Gleixnerconfig HOTPLUG_SPLIT_STARTUP
40a631be92SThomas Gleixner	bool
41a631be92SThomas Gleixner	select HOTPLUG_CORE_SYNC_FULL
42a631be92SThomas Gleixner
4318415f33SThomas Gleixnerconfig HOTPLUG_PARALLEL
4418415f33SThomas Gleixner	bool
4518415f33SThomas Gleixner	select HOTPLUG_SPLIT_STARTUP
4618415f33SThomas Gleixner
47142781e1SThomas Gleixnerconfig GENERIC_ENTRY
48142781e1SThomas Gleixner	bool
49142781e1SThomas Gleixner
50125e5645SMathieu Desnoyersconfig KPROBES
51125e5645SMathieu Desnoyers	bool "Kprobes"
5205ed160eSMasami Hiramatsu	depends on MODULES
53125e5645SMathieu Desnoyers	depends on HAVE_KPROBES
5405ed160eSMasami Hiramatsu	select KALLSYMS
55835f14edSPaul E. McKenney	select TASKS_RCU if PREEMPTION
56125e5645SMathieu Desnoyers	help
57125e5645SMathieu Desnoyers	  Kprobes allows you to trap at almost any kernel address and
58125e5645SMathieu Desnoyers	  execute a callback function.  register_kprobe() establishes
59125e5645SMathieu Desnoyers	  a probepoint and specifies the callback.  Kprobes is useful
60125e5645SMathieu Desnoyers	  for kernel debugging, non-intrusive instrumentation and testing.
61125e5645SMathieu Desnoyers	  If in doubt, say "N".
62125e5645SMathieu Desnoyers
6345f81b1cSSteven Rostedtconfig JUMP_LABEL
64c5905afbSIngo Molnar	bool "Optimize very unlikely/likely branches"
6545f81b1cSSteven Rostedt	depends on HAVE_ARCH_JUMP_LABEL
664ab7674fSJosh Poimboeuf	select OBJTOOL if HAVE_JUMP_LABEL_HACK
6745f81b1cSSteven Rostedt	help
68c5905afbSIngo Molnar	  This option enables a transparent branch optimization that
69c5905afbSIngo Molnar	  makes certain almost-always-true or almost-always-false branch
70c5905afbSIngo Molnar	  conditions even cheaper to execute within the kernel.
7145f81b1cSSteven Rostedt
72c5905afbSIngo Molnar	  Certain performance-sensitive kernel code, such as trace points,
73c5905afbSIngo Molnar	  scheduler functionality, networking code and KVM have such
74c5905afbSIngo Molnar	  branches and include support for this optimization technique.
75c5905afbSIngo Molnar
76c5905afbSIngo Molnar	  If it is detected that the compiler has support for "asm goto",
77c5905afbSIngo Molnar	  the kernel will compile such branches with just a nop
78c5905afbSIngo Molnar	  instruction. When the condition flag is toggled to true, the
79c5905afbSIngo Molnar	  nop will be converted to a jump instruction to execute the
80c5905afbSIngo Molnar	  conditional block of instructions.
81c5905afbSIngo Molnar
82c5905afbSIngo Molnar	  This technique lowers overhead and stress on the branch prediction
83c5905afbSIngo Molnar	  of the processor and generally makes the kernel faster. The update
84c5905afbSIngo Molnar	  of the condition is slower, but those are always very rare.
85c5905afbSIngo Molnar
86c5905afbSIngo Molnar	  ( On 32-bit x86, the necessary options added to the compiler
87c5905afbSIngo Molnar	    flags may increase the size of the kernel slightly. )
8845f81b1cSSteven Rostedt
891987c947SPeter Zijlstraconfig STATIC_KEYS_SELFTEST
901987c947SPeter Zijlstra	bool "Static key selftest"
911987c947SPeter Zijlstra	depends on JUMP_LABEL
921987c947SPeter Zijlstra	help
931987c947SPeter Zijlstra	  Boot time self-test of the branch patching code.
941987c947SPeter Zijlstra
95f03c4129SPeter Zijlstraconfig STATIC_CALL_SELFTEST
96f03c4129SPeter Zijlstra	bool "Static call selftest"
97f03c4129SPeter Zijlstra	depends on HAVE_STATIC_CALL
98f03c4129SPeter Zijlstra	help
99f03c4129SPeter Zijlstra	  Boot time self-test of the call patching code.
100f03c4129SPeter Zijlstra
101afd66255SMasami Hiramatsuconfig OPTPROBES
1025cc718b9SMasami Hiramatsu	def_bool y
1035cc718b9SMasami Hiramatsu	depends on KPROBES && HAVE_OPTPROBES
10401b1d88bSThomas Gleixner	select TASKS_RCU if PREEMPTION
105afd66255SMasami Hiramatsu
106e7dbfe34SMasami Hiramatsuconfig KPROBES_ON_FTRACE
107e7dbfe34SMasami Hiramatsu	def_bool y
108e7dbfe34SMasami Hiramatsu	depends on KPROBES && HAVE_KPROBES_ON_FTRACE
109e7dbfe34SMasami Hiramatsu	depends on DYNAMIC_FTRACE_WITH_REGS
110e7dbfe34SMasami Hiramatsu	help
111e7dbfe34SMasami Hiramatsu	  If function tracer is enabled and the arch supports full
112e7dbfe34SMasami Hiramatsu	  passing of pt_regs to function tracing, then kprobes can
113e7dbfe34SMasami Hiramatsu	  optimize on top of function tracing.
114e7dbfe34SMasami Hiramatsu
1152b144498SSrikar Dronamrajuconfig UPROBES
11609294e31SDavid A. Long	def_bool n
117e8f4aa60SAllen Pais	depends on ARCH_SUPPORTS_UPROBES
1182b144498SSrikar Dronamraju	help
1197b2d81d4SIngo Molnar	  Uprobes is the user-space counterpart to kprobes: they
1207b2d81d4SIngo Molnar	  enable instrumentation applications (such as 'perf probe')
1217b2d81d4SIngo Molnar	  to establish unintrusive probes in user-space binaries and
1227b2d81d4SIngo Molnar	  libraries, by executing handler functions when the probes
1237b2d81d4SIngo Molnar	  are hit by user-space applications.
1247b2d81d4SIngo Molnar
1257b2d81d4SIngo Molnar	  ( These probes come in the form of single-byte breakpoints,
1267b2d81d4SIngo Molnar	    managed by the kernel and kept transparent to the probed
1277b2d81d4SIngo Molnar	    application. )
1282b144498SSrikar Dronamraju
129adab66b7SSteven Rostedt (VMware)config HAVE_64BIT_ALIGNED_ACCESS
130adab66b7SSteven Rostedt (VMware)	def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
131adab66b7SSteven Rostedt (VMware)	help
132adab66b7SSteven Rostedt (VMware)	  Some architectures require 64 bit accesses to be 64 bit
133adab66b7SSteven Rostedt (VMware)	  aligned, which also requires structs containing 64 bit values
134adab66b7SSteven Rostedt (VMware)	  to be 64 bit aligned too. This includes some 32 bit
135adab66b7SSteven Rostedt (VMware)	  architectures which can do 64 bit accesses, as well as 64 bit
136adab66b7SSteven Rostedt (VMware)	  architectures without unaligned access.
137adab66b7SSteven Rostedt (VMware)
138adab66b7SSteven Rostedt (VMware)	  This symbol should be selected by an architecture if 64 bit
139adab66b7SSteven Rostedt (VMware)	  accesses are required to be 64 bit aligned in this way even
140adab66b7SSteven Rostedt (VMware)	  though it is not a 64 bit architecture.
141adab66b7SSteven Rostedt (VMware)
142ba1a297dSLukas Bulwahn	  See Documentation/core-api/unaligned-memory-access.rst for
143ba1a297dSLukas Bulwahn	  more information on the topic of unaligned memory accesses.
144adab66b7SSteven Rostedt (VMware)
14558340a07SJohannes Bergconfig HAVE_EFFICIENT_UNALIGNED_ACCESS
1469ba16087SJan Beulich	bool
14758340a07SJohannes Berg	help
14858340a07SJohannes Berg	  Some architectures are unable to perform unaligned accesses
14958340a07SJohannes Berg	  without the use of get_unaligned/put_unaligned. Others are
15058340a07SJohannes Berg	  unable to perform such accesses efficiently (e.g. trap on
15158340a07SJohannes Berg	  unaligned access and require fixing it up in the exception
15258340a07SJohannes Berg	  handler.)
15358340a07SJohannes Berg
15458340a07SJohannes Berg	  This symbol should be selected by an architecture if it can
15558340a07SJohannes Berg	  perform unaligned accesses efficiently to allow different
15658340a07SJohannes Berg	  code paths to be selected for these cases. Some network
15758340a07SJohannes Berg	  drivers, for example, could opt to not fix up alignment
15858340a07SJohannes Berg	  problems with received packets if doing so would not help
15958340a07SJohannes Berg	  much.
16058340a07SJohannes Berg
161c9b54d6fSMauro Carvalho Chehab	  See Documentation/core-api/unaligned-memory-access.rst for more
16258340a07SJohannes Berg	  information on the topic of unaligned memory accesses.
16358340a07SJohannes Berg
164cf66bb93SDavid Woodhouseconfig ARCH_USE_BUILTIN_BSWAP
165cf66bb93SDavid Woodhouse	bool
166cf66bb93SDavid Woodhouse	help
167cf66bb93SDavid Woodhouse	  Modern versions of GCC (since 4.4) have builtin functions
168cf66bb93SDavid Woodhouse	  for handling byte-swapping. Using these, instead of the old
169cf66bb93SDavid Woodhouse	  inline assembler that the architecture code provides in the
170cf66bb93SDavid Woodhouse	  __arch_bswapXX() macros, allows the compiler to see what's
171cf66bb93SDavid Woodhouse	  happening and offers more opportunity for optimisation. In
172cf66bb93SDavid Woodhouse	  particular, the compiler will be able to combine the byteswap
173cf66bb93SDavid Woodhouse	  with a nearby load or store and use load-and-swap or
174cf66bb93SDavid Woodhouse	  store-and-swap instructions if the architecture has them. It
175cf66bb93SDavid Woodhouse	  should almost *never* result in code which is worse than the
176cf66bb93SDavid Woodhouse	  hand-coded assembler in <asm/swab.h>.  But just in case it
177cf66bb93SDavid Woodhouse	  does, the use of the builtins is optional.
178cf66bb93SDavid Woodhouse
179cf66bb93SDavid Woodhouse	  Any architecture with load-and-swap or store-and-swap
180cf66bb93SDavid Woodhouse	  instructions should set this. And it shouldn't hurt to set it
181cf66bb93SDavid Woodhouse	  on architectures that don't have such instructions.
182cf66bb93SDavid Woodhouse
1839edddaa2SAnanth N Mavinakayanahalliconfig KRETPROBES
1849edddaa2SAnanth N Mavinakayanahalli	def_bool y
18573f9b911SMasami Hiramatsu	depends on KPROBES && (HAVE_KRETPROBES || HAVE_RETHOOK)
18673f9b911SMasami Hiramatsu
18773f9b911SMasami Hiramatsuconfig KRETPROBE_ON_RETHOOK
18873f9b911SMasami Hiramatsu	def_bool y
18973f9b911SMasami Hiramatsu	depends on HAVE_RETHOOK
19073f9b911SMasami Hiramatsu	depends on KRETPROBES
19173f9b911SMasami Hiramatsu	select RETHOOK
1929edddaa2SAnanth N Mavinakayanahalli
1937c68af6eSAvi Kivityconfig USER_RETURN_NOTIFIER
1947c68af6eSAvi Kivity	bool
1957c68af6eSAvi Kivity	depends on HAVE_USER_RETURN_NOTIFIER
1967c68af6eSAvi Kivity	help
1977c68af6eSAvi Kivity	  Provide a kernel-internal notification when a cpu is about to
1987c68af6eSAvi Kivity	  switch to user mode.
1997c68af6eSAvi Kivity
20028b2ee20SRik van Rielconfig HAVE_IOREMAP_PROT
2019ba16087SJan Beulich	bool
20228b2ee20SRik van Riel
203125e5645SMathieu Desnoyersconfig HAVE_KPROBES
2049ba16087SJan Beulich	bool
2059edddaa2SAnanth N Mavinakayanahalli
2069edddaa2SAnanth N Mavinakayanahalliconfig HAVE_KRETPROBES
2079ba16087SJan Beulich	bool
20874bc7ceeSArthur Kepner
209afd66255SMasami Hiramatsuconfig HAVE_OPTPROBES
210afd66255SMasami Hiramatsu	bool
211d314d74cSCong Wang
212e7dbfe34SMasami Hiramatsuconfig HAVE_KPROBES_ON_FTRACE
213e7dbfe34SMasami Hiramatsu	bool
214e7dbfe34SMasami Hiramatsu
2151f6d3a8fSMasami Hiramatsuconfig ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2161f6d3a8fSMasami Hiramatsu	bool
2171f6d3a8fSMasami Hiramatsu	help
2181f6d3a8fSMasami Hiramatsu	  Since kretprobes modifies return address on the stack, the
2191f6d3a8fSMasami Hiramatsu	  stacktrace may see the kretprobe trampoline address instead
2201f6d3a8fSMasami Hiramatsu	  of correct one. If the architecture stacktrace code and
2211f6d3a8fSMasami Hiramatsu	  unwinder can adjust such entries, select this configuration.
2221f6d3a8fSMasami Hiramatsu
223540adea3SMasami Hiramatsuconfig HAVE_FUNCTION_ERROR_INJECTION
2249802d865SJosef Bacik	bool
2259802d865SJosef Bacik
22642a0bb3fSPetr Mladekconfig HAVE_NMI
22742a0bb3fSPetr Mladek	bool
22842a0bb3fSPetr Mladek
229a257caccSChristophe Leroyconfig HAVE_FUNCTION_DESCRIPTORS
230a257caccSChristophe Leroy	bool
231a257caccSChristophe Leroy
2324aae683fSMasahiro Yamadaconfig TRACE_IRQFLAGS_SUPPORT
2334aae683fSMasahiro Yamada	bool
2344aae683fSMasahiro Yamada
2354510bffbSMark Rutlandconfig TRACE_IRQFLAGS_NMI_SUPPORT
2364510bffbSMark Rutland	bool
2374510bffbSMark Rutland
2381f5a4ad9SRoland McGrath#
2391f5a4ad9SRoland McGrath# An arch should select this if it provides all these things:
2401f5a4ad9SRoland McGrath#
2411f5a4ad9SRoland McGrath#	task_pt_regs()		in asm/processor.h or asm/ptrace.h
2421f5a4ad9SRoland McGrath#	arch_has_single_step()	if there is hardware single-step support
2431f5a4ad9SRoland McGrath#	arch_has_block_step()	if there is hardware block-step support
2441f5a4ad9SRoland McGrath#	asm/syscall.h		supplying asm-generic/syscall.h interface
2451f5a4ad9SRoland McGrath#	linux/regset.h		user_regset interfaces
2461f5a4ad9SRoland McGrath#	CORE_DUMP_USE_REGSET	#define'd in linux/elf.h
247153474baSEric W. Biederman#	TIF_SYSCALL_TRACE	calls ptrace_report_syscall_{entry,exit}
24803248addSEric W. Biederman#	TIF_NOTIFY_RESUME	calls resume_user_mode_work()
2491f5a4ad9SRoland McGrath#
2501f5a4ad9SRoland McGrathconfig HAVE_ARCH_TRACEHOOK
2519ba16087SJan Beulich	bool
2521f5a4ad9SRoland McGrath
253c64be2bbSMarek Szyprowskiconfig HAVE_DMA_CONTIGUOUS
254c64be2bbSMarek Szyprowski	bool
255c64be2bbSMarek Szyprowski
25629d5e047SThomas Gleixnerconfig GENERIC_SMP_IDLE_THREAD
25729d5e047SThomas Gleixner	bool
25829d5e047SThomas Gleixner
259485cf5daSKevin Hilmanconfig GENERIC_IDLE_POLL_SETUP
260485cf5daSKevin Hilman	bool
261485cf5daSKevin Hilman
2626974f0c4SDaniel Micayconfig ARCH_HAS_FORTIFY_SOURCE
2636974f0c4SDaniel Micay	bool
2646974f0c4SDaniel Micay	help
2656974f0c4SDaniel Micay	  An architecture should select this when it can successfully
2666974f0c4SDaniel Micay	  build and run with CONFIG_FORTIFY_SOURCE.
2676974f0c4SDaniel Micay
268d8ae8a37SChristoph Hellwig#
269d8ae8a37SChristoph Hellwig# Select if the arch provides a historic keepinit alias for the retain_initrd
270d8ae8a37SChristoph Hellwig# command line option
271d8ae8a37SChristoph Hellwig#
272d8ae8a37SChristoph Hellwigconfig ARCH_HAS_KEEPINITRD
273d8ae8a37SChristoph Hellwig	bool
274d8ae8a37SChristoph Hellwig
275d2852a22SDaniel Borkmann# Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
276d2852a22SDaniel Borkmannconfig ARCH_HAS_SET_MEMORY
277d2852a22SDaniel Borkmann	bool
278d2852a22SDaniel Borkmann
279d253ca0cSRick Edgecombe# Select if arch has all set_direct_map_invalid/default() functions
280d253ca0cSRick Edgecombeconfig ARCH_HAS_SET_DIRECT_MAP
281d253ca0cSRick Edgecombe	bool
282d253ca0cSRick Edgecombe
283c30700dbSChristoph Hellwig#
284fa7e2247SChristoph Hellwig# Select if the architecture provides the arch_dma_set_uncached symbol to
285a86ecfa6SColin Ian King# either provide an uncached segment alias for a DMA allocation, or
286fa7e2247SChristoph Hellwig# to remap the page tables in place.
287c30700dbSChristoph Hellwig#
288fa7e2247SChristoph Hellwigconfig ARCH_HAS_DMA_SET_UNCACHED
289c30700dbSChristoph Hellwig	bool
290c30700dbSChristoph Hellwig
291999a5d12SChristoph Hellwig#
292999a5d12SChristoph Hellwig# Select if the architectures provides the arch_dma_clear_uncached symbol
293999a5d12SChristoph Hellwig# to undo an in-place page table remap for uncached access.
294999a5d12SChristoph Hellwig#
295999a5d12SChristoph Hellwigconfig ARCH_HAS_DMA_CLEAR_UNCACHED
296f5e10287SThomas Gleixner	bool
297f5e10287SThomas Gleixner
2987725acaaSThomas Gleixnerconfig ARCH_HAS_CPU_FINALIZE_INIT
2997725acaaSThomas Gleixner	bool
3007725acaaSThomas Gleixner
301a6359d1eSThomas Gleixner# Select if arch init_task must go in the __init_task_data section
302a6359d1eSThomas Gleixnerconfig ARCH_TASK_STRUCT_ON_STACK
303a4a2eb49SThomas Gleixner	bool
304a4a2eb49SThomas Gleixner
305f5e10287SThomas Gleixner# Select if arch has its private alloc_task_struct() function
306f5e10287SThomas Gleixnerconfig ARCH_TASK_STRUCT_ALLOCATOR
307f5e10287SThomas Gleixner	bool
308f5e10287SThomas Gleixner
3095905429aSKees Cookconfig HAVE_ARCH_THREAD_STRUCT_WHITELIST
3105905429aSKees Cook	bool
3115905429aSKees Cook	depends on !ARCH_TASK_STRUCT_ALLOCATOR
3125905429aSKees Cook	help
3135905429aSKees Cook	  An architecture should select this to provide hardened usercopy
3145905429aSKees Cook	  knowledge about what region of the thread_struct should be
3155905429aSKees Cook	  whitelisted for copying to userspace. Normally this is only the
3165905429aSKees Cook	  FPU registers. Specifically, arch_thread_struct_whitelist()
3175905429aSKees Cook	  should be implemented. Without this, the entire thread_struct
3185905429aSKees Cook	  field in task_struct will be left whitelisted.
3195905429aSKees Cook
320b235beeaSLinus Torvalds# Select if arch has its private alloc_thread_stack() function
321b235beeaSLinus Torvaldsconfig ARCH_THREAD_STACK_ALLOCATOR
322f5e10287SThomas Gleixner	bool
323f5e10287SThomas Gleixner
3245aaeb5c0SIngo Molnar# Select if arch wants to size task_struct dynamically via arch_task_struct_size:
3255aaeb5c0SIngo Molnarconfig ARCH_WANTS_DYNAMIC_TASK_STRUCT
3265aaeb5c0SIngo Molnar	bool
3275aaeb5c0SIngo Molnar
32851c2ee6dSNick Desaulniersconfig ARCH_WANTS_NO_INSTR
32951c2ee6dSNick Desaulniers	bool
33051c2ee6dSNick Desaulniers	help
33151c2ee6dSNick Desaulniers	  An architecture should select this if the noinstr macro is being used on
33251c2ee6dSNick Desaulniers	  functions to denote that the toolchain should avoid instrumenting such
33351c2ee6dSNick Desaulniers	  functions and is required for correctness.
33451c2ee6dSNick Desaulniers
335942fa985SYury Norovconfig ARCH_32BIT_OFF_T
336942fa985SYury Norov	bool
337942fa985SYury Norov	depends on !64BIT
338942fa985SYury Norov	help
339942fa985SYury Norov	  All new 32-bit architectures should have 64-bit off_t type on
340942fa985SYury Norov	  userspace side which corresponds to the loff_t kernel type. This
341942fa985SYury Norov	  is the requirement for modern ABIs. Some existing architectures
342942fa985SYury Norov	  still support 32-bit off_t. This option is enabled for all such
343942fa985SYury Norov	  architectures explicitly.
344942fa985SYury Norov
34596c0a6a7SHeiko Carstens# Selected by 64 bit architectures which have a 32 bit f_tinode in struct ustat
34696c0a6a7SHeiko Carstensconfig ARCH_32BIT_USTAT_F_TINODE
34796c0a6a7SHeiko Carstens	bool
34896c0a6a7SHeiko Carstens
3492ff2b7ecSMasahiro Yamadaconfig HAVE_ASM_MODVERSIONS
3502ff2b7ecSMasahiro Yamada	bool
3512ff2b7ecSMasahiro Yamada	help
352a86ecfa6SColin Ian King	  This symbol should be selected by an architecture if it provides
3532ff2b7ecSMasahiro Yamada	  <asm/asm-prototypes.h> to support the module versioning for symbols
3542ff2b7ecSMasahiro Yamada	  exported from assembly code.
3552ff2b7ecSMasahiro Yamada
356f850c30cSHeiko Carstensconfig HAVE_REGS_AND_STACK_ACCESS_API
357f850c30cSHeiko Carstens	bool
358e01292b1SHeiko Carstens	help
359a86ecfa6SColin Ian King	  This symbol should be selected by an architecture if it supports
360e01292b1SHeiko Carstens	  the API needed to access registers and stack entries from pt_regs,
361e01292b1SHeiko Carstens	  declared in asm/ptrace.h
362e01292b1SHeiko Carstens	  For example the kprobes-based event tracer needs this API.
363f850c30cSHeiko Carstens
364d7822b1eSMathieu Desnoyersconfig HAVE_RSEQ
365d7822b1eSMathieu Desnoyers	bool
366d7822b1eSMathieu Desnoyers	depends on HAVE_REGS_AND_STACK_ACCESS_API
367d7822b1eSMathieu Desnoyers	help
368d7822b1eSMathieu Desnoyers	  This symbol should be selected by an architecture if it
369d7822b1eSMathieu Desnoyers	  supports an implementation of restartable sequences.
370d7822b1eSMathieu Desnoyers
3712f7ab126SMiguel Ojedaconfig HAVE_RUST
3722f7ab126SMiguel Ojeda	bool
3732f7ab126SMiguel Ojeda	help
3742f7ab126SMiguel Ojeda	  This symbol should be selected by an architecture if it
3752f7ab126SMiguel Ojeda	  supports Rust.
3762f7ab126SMiguel Ojeda
3773c88ee19SMasami Hiramatsuconfig HAVE_FUNCTION_ARG_ACCESS_API
3783c88ee19SMasami Hiramatsu	bool
3793c88ee19SMasami Hiramatsu	help
380a86ecfa6SColin Ian King	  This symbol should be selected by an architecture if it supports
3813c88ee19SMasami Hiramatsu	  the API needed to access function arguments from pt_regs,
3823c88ee19SMasami Hiramatsu	  declared in asm/ptrace.h
3833c88ee19SMasami Hiramatsu
38462a038d3SK.Prasadconfig HAVE_HW_BREAKPOINT
38562a038d3SK.Prasad	bool
38699e8c5a3SFrederic Weisbecker	depends on PERF_EVENTS
38762a038d3SK.Prasad
3880102752eSFrederic Weisbeckerconfig HAVE_MIXED_BREAKPOINTS_REGS
3890102752eSFrederic Weisbecker	bool
3900102752eSFrederic Weisbecker	depends on HAVE_HW_BREAKPOINT
3910102752eSFrederic Weisbecker	help
3920102752eSFrederic Weisbecker	  Depending on the arch implementation of hardware breakpoints,
3930102752eSFrederic Weisbecker	  some of them have separate registers for data and instruction
3940102752eSFrederic Weisbecker	  breakpoints addresses, others have mixed registers to store
3950102752eSFrederic Weisbecker	  them but define the access type in a control register.
3960102752eSFrederic Weisbecker	  Select this option if your arch implements breakpoints under the
3970102752eSFrederic Weisbecker	  latter fashion.
3980102752eSFrederic Weisbecker
3997c68af6eSAvi Kivityconfig HAVE_USER_RETURN_NOTIFIER
4007c68af6eSAvi Kivity	bool
401a1922ed6SIngo Molnar
402c01d4323SFrederic Weisbeckerconfig HAVE_PERF_EVENTS_NMI
403c01d4323SFrederic Weisbecker	bool
40423637d47SFrederic Weisbecker	help
40523637d47SFrederic Weisbecker	  System hardware can generate an NMI using the perf event
40623637d47SFrederic Weisbecker	  subsystem.  Also has support for calculating CPU cycle events
40723637d47SFrederic Weisbecker	  to determine how many clock cycles in a given period.
408c01d4323SFrederic Weisbecker
40905a4a952SNicholas Pigginconfig HAVE_HARDLOCKUP_DETECTOR_PERF
41005a4a952SNicholas Piggin	bool
41105a4a952SNicholas Piggin	depends on HAVE_PERF_EVENTS_NMI
41205a4a952SNicholas Piggin	help
41305a4a952SNicholas Piggin	  The arch chooses to use the generic perf-NMI-based hardlockup
41405a4a952SNicholas Piggin	  detector. Must define HAVE_PERF_EVENTS_NMI.
41505a4a952SNicholas Piggin
41605a4a952SNicholas Pigginconfig HAVE_HARDLOCKUP_DETECTOR_ARCH
41705a4a952SNicholas Piggin	bool
41805a4a952SNicholas Piggin	help
4191356d0b9SPetr Mladek	  The arch provides its own hardlockup detector implementation instead
4201356d0b9SPetr Mladek	  of the generic ones.
4211356d0b9SPetr Mladek
4221356d0b9SPetr Mladek	  It uses the same command line parameters, and sysctl interface,
4231356d0b9SPetr Mladek	  as the generic hardlockup detectors.
42405a4a952SNicholas Piggin
425c5e63197SJiri Olsaconfig HAVE_PERF_REGS
426c5e63197SJiri Olsa	bool
427c5e63197SJiri Olsa	help
428c5e63197SJiri Olsa	  Support selective register dumps for perf events. This includes
429c5e63197SJiri Olsa	  bit-mapping of each registers and a unique architecture id.
430c5e63197SJiri Olsa
431c5ebcedbSJiri Olsaconfig HAVE_PERF_USER_STACK_DUMP
432c5ebcedbSJiri Olsa	bool
433c5ebcedbSJiri Olsa	help
434c5ebcedbSJiri Olsa	  Support user stack dumps for perf event samples. This needs
435c5ebcedbSJiri Olsa	  access to the user stack pointer which is not unified across
436c5ebcedbSJiri Olsa	  architectures.
437c5ebcedbSJiri Olsa
438bf5438fcSJason Baronconfig HAVE_ARCH_JUMP_LABEL
439bf5438fcSJason Baron	bool
440bf5438fcSJason Baron
44150ff18abSArd Biesheuvelconfig HAVE_ARCH_JUMP_LABEL_RELATIVE
44250ff18abSArd Biesheuvel	bool
44350ff18abSArd Biesheuvel
4440d6e24d4SPeter Zijlstraconfig MMU_GATHER_TABLE_FREE
4450d6e24d4SPeter Zijlstra	bool
4460d6e24d4SPeter Zijlstra
447ff2e6d72SPeter Zijlstraconfig MMU_GATHER_RCU_TABLE_FREE
44826723911SPeter Zijlstra	bool
4490d6e24d4SPeter Zijlstra	select MMU_GATHER_TABLE_FREE
45026723911SPeter Zijlstra
4513af4bd03SPeter Zijlstraconfig MMU_GATHER_PAGE_SIZE
452ed6a7935SPeter Zijlstra	bool
453ed6a7935SPeter Zijlstra
45427796d03SPeter Zijlstraconfig MMU_GATHER_NO_RANGE
45527796d03SPeter Zijlstra	bool
4561e9fdf21SPeter Zijlstra	select MMU_GATHER_MERGE_VMAS
4571e9fdf21SPeter Zijlstra
4581e9fdf21SPeter Zijlstraconfig MMU_GATHER_NO_FLUSH_CACHE
4591e9fdf21SPeter Zijlstra	bool
4601e9fdf21SPeter Zijlstra
4611e9fdf21SPeter Zijlstraconfig MMU_GATHER_MERGE_VMAS
4621e9fdf21SPeter Zijlstra	bool
46327796d03SPeter Zijlstra
464580a586cSPeter Zijlstraconfig MMU_GATHER_NO_GATHER
465952a31c9SMartin Schwidefsky	bool
4660d6e24d4SPeter Zijlstra	depends on MMU_GATHER_TABLE_FREE
467952a31c9SMartin Schwidefsky
468d53c3dfbSNicholas Pigginconfig ARCH_WANT_IRQS_OFF_ACTIVATE_MM
469d53c3dfbSNicholas Piggin	bool
470d53c3dfbSNicholas Piggin	help
471d53c3dfbSNicholas Piggin	  Temporary select until all architectures can be converted to have
472d53c3dfbSNicholas Piggin	  irqs disabled over activate_mm. Architectures that do IPI based TLB
473d53c3dfbSNicholas Piggin	  shootdowns should enable this.
474d53c3dfbSNicholas Piggin
47588e3009bSNicholas Piggin# Use normal mm refcounting for MMU_LAZY_TLB kernel thread references.
47688e3009bSNicholas Piggin# MMU_LAZY_TLB_REFCOUNT=n can improve the scalability of context switching
47788e3009bSNicholas Piggin# to/from kernel threads when the same mm is running on a lot of CPUs (a large
47888e3009bSNicholas Piggin# multi-threaded application), by reducing contention on the mm refcount.
47988e3009bSNicholas Piggin#
48088e3009bSNicholas Piggin# This can be disabled if the architecture ensures no CPUs are using an mm as a
48188e3009bSNicholas Piggin# "lazy tlb" beyond its final refcount (i.e., by the time __mmdrop frees the mm
48288e3009bSNicholas Piggin# or its kernel page tables). This could be arranged by arch_exit_mmap(), or
48388e3009bSNicholas Piggin# final exit(2) TLB flush, for example.
48488e3009bSNicholas Piggin#
48588e3009bSNicholas Piggin# To implement this, an arch *must*:
48688e3009bSNicholas Piggin# Ensure the _lazy_tlb variants of mmgrab/mmdrop are used when manipulating
48788e3009bSNicholas Piggin# the lazy tlb reference of a kthread's ->active_mm (non-arch code has been
48888e3009bSNicholas Piggin# converted already).
48988e3009bSNicholas Pigginconfig MMU_LAZY_TLB_REFCOUNT
49088e3009bSNicholas Piggin	def_bool y
4912655421aSNicholas Piggin	depends on !MMU_LAZY_TLB_SHOOTDOWN
4922655421aSNicholas Piggin
4932655421aSNicholas Piggin# This option allows MMU_LAZY_TLB_REFCOUNT=n. It ensures no CPUs are using an
4942655421aSNicholas Piggin# mm as a lazy tlb beyond its last reference count, by shooting down these
4952655421aSNicholas Piggin# users before the mm is deallocated. __mmdrop() first IPIs all CPUs that may
4962655421aSNicholas Piggin# be using the mm as a lazy tlb, so that they may switch themselves to using
4972655421aSNicholas Piggin# init_mm for their active mm. mm_cpumask(mm) is used to determine which CPUs
4982655421aSNicholas Piggin# may be using mm as a lazy tlb mm.
4992655421aSNicholas Piggin#
5002655421aSNicholas Piggin# To implement this, an arch *must*:
5012655421aSNicholas Piggin# - At the time of the final mmdrop of the mm, ensure mm_cpumask(mm) contains
5022655421aSNicholas Piggin#   at least all possible CPUs in which the mm is lazy.
5032655421aSNicholas Piggin# - It must meet the requirements for MMU_LAZY_TLB_REFCOUNT=n (see above).
5042655421aSNicholas Pigginconfig MMU_LAZY_TLB_SHOOTDOWN
5052655421aSNicholas Piggin	bool
50688e3009bSNicholas Piggin
507df013ffbSHuang Yingconfig ARCH_HAVE_NMI_SAFE_CMPXCHG
508df013ffbSHuang Ying	bool
509df013ffbSHuang Ying
5102e83b879SPaul E. McKenneyconfig ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
5112e83b879SPaul E. McKenney	bool
5122e83b879SPaul E. McKenney
51343570fd2SHeiko Carstensconfig HAVE_ALIGNED_STRUCT_PAGE
51443570fd2SHeiko Carstens	bool
51543570fd2SHeiko Carstens	help
51643570fd2SHeiko Carstens	  This makes sure that struct pages are double word aligned and that
51743570fd2SHeiko Carstens	  e.g. the SLUB allocator can perform double word atomic operations
51843570fd2SHeiko Carstens	  on a struct page for better performance. However selecting this
51943570fd2SHeiko Carstens	  might increase the size of a struct page by a word.
52043570fd2SHeiko Carstens
5214156153cSHeiko Carstensconfig HAVE_CMPXCHG_LOCAL
5224156153cSHeiko Carstens	bool
5234156153cSHeiko Carstens
5242565409fSHeiko Carstensconfig HAVE_CMPXCHG_DOUBLE
5252565409fSHeiko Carstens	bool
5262565409fSHeiko Carstens
52777e58496SPaul E. McKenneyconfig ARCH_WEAK_RELEASE_ACQUIRE
52877e58496SPaul E. McKenney	bool
52977e58496SPaul E. McKenney
530c1d7e01dSWill Deaconconfig ARCH_WANT_IPC_PARSE_VERSION
531c1d7e01dSWill Deacon	bool
532c1d7e01dSWill Deacon
533c1d7e01dSWill Deaconconfig ARCH_WANT_COMPAT_IPC_PARSE_VERSION
534c1d7e01dSWill Deacon	bool
535c1d7e01dSWill Deacon
53648b25c43SChris Metcalfconfig ARCH_WANT_OLD_COMPAT_IPC
537c1d7e01dSWill Deacon	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
53848b25c43SChris Metcalf	bool
53948b25c43SChris Metcalf
540282a181bSYiFei Zhuconfig HAVE_ARCH_SECCOMP
541e2cfabdfSWill Drewry	bool
542e2cfabdfSWill Drewry	help
543282a181bSYiFei Zhu	  An arch should select this symbol to support seccomp mode 1 (the fixed
544282a181bSYiFei Zhu	  syscall policy), and must provide an overrides for __NR_seccomp_sigreturn,
545282a181bSYiFei Zhu	  and compat syscalls if the asm-generic/seccomp.h defaults need adjustment:
546282a181bSYiFei Zhu	  - __NR_seccomp_read_32
547282a181bSYiFei Zhu	  - __NR_seccomp_write_32
548282a181bSYiFei Zhu	  - __NR_seccomp_exit_32
549282a181bSYiFei Zhu	  - __NR_seccomp_sigreturn_32
550282a181bSYiFei Zhu
551282a181bSYiFei Zhuconfig HAVE_ARCH_SECCOMP_FILTER
552282a181bSYiFei Zhu	bool
553282a181bSYiFei Zhu	select HAVE_ARCH_SECCOMP
554282a181bSYiFei Zhu	help
555fb0fadf9SWill Drewry	  An arch should select this symbol if it provides all of these things:
556282a181bSYiFei Zhu	  - all the requirements for HAVE_ARCH_SECCOMP
557bb6ea430SWill Drewry	  - syscall_get_arch()
558bb6ea430SWill Drewry	  - syscall_get_arguments()
559bb6ea430SWill Drewry	  - syscall_rollback()
560bb6ea430SWill Drewry	  - syscall_set_return_value()
561fb0fadf9SWill Drewry	  - SIGSYS siginfo_t support
562fb0fadf9SWill Drewry	  - secure_computing is called from a ptrace_event()-safe context
563fb0fadf9SWill Drewry	  - secure_computing return value is checked and a return value of -1
564fb0fadf9SWill Drewry	    results in the system call being skipped immediately.
56548dc92b9SKees Cook	  - seccomp syscall wired up
5660d8315ddSYiFei Zhu	  - if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE,
5670d8315ddSYiFei Zhu	    SECCOMP_ARCH_NATIVE_NR, SECCOMP_ARCH_NATIVE_NAME defined. If
5680d8315ddSYiFei Zhu	    COMPAT is supported, have the SECCOMP_ARCH_COMPAT* defines too.
569e2cfabdfSWill Drewry
570282a181bSYiFei Zhuconfig SECCOMP
571282a181bSYiFei Zhu	prompt "Enable seccomp to safely execute untrusted bytecode"
572282a181bSYiFei Zhu	def_bool y
573282a181bSYiFei Zhu	depends on HAVE_ARCH_SECCOMP
574282a181bSYiFei Zhu	help
575282a181bSYiFei Zhu	  This kernel feature is useful for number crunching applications
576282a181bSYiFei Zhu	  that may need to handle untrusted bytecode during their
577282a181bSYiFei Zhu	  execution. By using pipes or other transports made available
578282a181bSYiFei Zhu	  to the process as file descriptors supporting the read/write
579282a181bSYiFei Zhu	  syscalls, it's possible to isolate those applications in their
580282a181bSYiFei Zhu	  own address space using seccomp. Once seccomp is enabled via
581282a181bSYiFei Zhu	  prctl(PR_SET_SECCOMP) or the seccomp() syscall, it cannot be
582282a181bSYiFei Zhu	  disabled and the task is only allowed to execute a few safe
583282a181bSYiFei Zhu	  syscalls defined by each seccomp mode.
584282a181bSYiFei Zhu
585282a181bSYiFei Zhu	  If unsure, say Y.
586282a181bSYiFei Zhu
587e2cfabdfSWill Drewryconfig SECCOMP_FILTER
588e2cfabdfSWill Drewry	def_bool y
589e2cfabdfSWill Drewry	depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
590e2cfabdfSWill Drewry	help
591e2cfabdfSWill Drewry	  Enable tasks to build secure computing environments defined
592e2cfabdfSWill Drewry	  in terms of Berkeley Packet Filter programs which implement
593e2cfabdfSWill Drewry	  task-defined system call filtering polices.
594e2cfabdfSWill Drewry
5955fb94e9cSMauro Carvalho Chehab	  See Documentation/userspace-api/seccomp_filter.rst for details.
596e2cfabdfSWill Drewry
5970d8315ddSYiFei Zhuconfig SECCOMP_CACHE_DEBUG
5980d8315ddSYiFei Zhu	bool "Show seccomp filter cache status in /proc/pid/seccomp_cache"
5990d8315ddSYiFei Zhu	depends on SECCOMP_FILTER && !HAVE_SPARSE_SYSCALL_NR
6000d8315ddSYiFei Zhu	depends on PROC_FS
6010d8315ddSYiFei Zhu	help
6020d8315ddSYiFei Zhu	  This enables the /proc/pid/seccomp_cache interface to monitor
6030d8315ddSYiFei Zhu	  seccomp cache data. The file format is subject to change. Reading
6040d8315ddSYiFei Zhu	  the file requires CAP_SYS_ADMIN.
6050d8315ddSYiFei Zhu
6060d8315ddSYiFei Zhu	  This option is for debugging only. Enabling presents the risk that
6070d8315ddSYiFei Zhu	  an adversary may be able to infer the seccomp filter logic.
6080d8315ddSYiFei Zhu
6090d8315ddSYiFei Zhu	  If unsure, say N.
6100d8315ddSYiFei Zhu
611afaef01cSAlexander Popovconfig HAVE_ARCH_STACKLEAK
612afaef01cSAlexander Popov	bool
613afaef01cSAlexander Popov	help
614afaef01cSAlexander Popov	  An architecture should select this if it has the code which
615afaef01cSAlexander Popov	  fills the used part of the kernel stack with the STACKLEAK_POISON
616afaef01cSAlexander Popov	  value before returning from system calls.
617afaef01cSAlexander Popov
618d148eac0SMasahiro Yamadaconfig HAVE_STACKPROTECTOR
61919952a92SKees Cook	bool
62019952a92SKees Cook	help
62119952a92SKees Cook	  An arch should select this symbol if:
62219952a92SKees Cook	  - it has implemented a stack canary (e.g. __stack_chk_guard)
62319952a92SKees Cook
624050e9baaSLinus Torvaldsconfig STACKPROTECTOR
6252a61f474SMasahiro Yamada	bool "Stack Protector buffer overflow detection"
626d148eac0SMasahiro Yamada	depends on HAVE_STACKPROTECTOR
6272a61f474SMasahiro Yamada	depends on $(cc-option,-fstack-protector)
6282a61f474SMasahiro Yamada	default y
6298779657dSKees Cook	help
6308779657dSKees Cook	  This option turns on the "stack-protector" GCC feature. This
63119952a92SKees Cook	  feature puts, at the beginning of functions, a canary value on
63219952a92SKees Cook	  the stack just before the return address, and validates
63319952a92SKees Cook	  the value just before actually returning.  Stack based buffer
63419952a92SKees Cook	  overflows (that need to overwrite this return address) now also
63519952a92SKees Cook	  overwrite the canary, which gets detected and the attack is then
63619952a92SKees Cook	  neutralized via a kernel panic.
63719952a92SKees Cook
6388779657dSKees Cook	  Functions will have the stack-protector canary logic added if they
6398779657dSKees Cook	  have an 8-byte or larger character array on the stack.
6408779657dSKees Cook
64119952a92SKees Cook	  This feature requires gcc version 4.2 or above, or a distribution
6428779657dSKees Cook	  gcc with the feature backported ("-fstack-protector").
6438779657dSKees Cook
6448779657dSKees Cook	  On an x86 "defconfig" build, this feature adds canary checks to
6458779657dSKees Cook	  about 3% of all kernel functions, which increases kernel code size
6468779657dSKees Cook	  by about 0.3%.
6478779657dSKees Cook
648050e9baaSLinus Torvaldsconfig STACKPROTECTOR_STRONG
6492a61f474SMasahiro Yamada	bool "Strong Stack Protector"
650050e9baaSLinus Torvalds	depends on STACKPROTECTOR
6512a61f474SMasahiro Yamada	depends on $(cc-option,-fstack-protector-strong)
6522a61f474SMasahiro Yamada	default y
6538779657dSKees Cook	help
6548779657dSKees Cook	  Functions will have the stack-protector canary logic added in any
6558779657dSKees Cook	  of the following conditions:
6568779657dSKees Cook
6578779657dSKees Cook	  - local variable's address used as part of the right hand side of an
6588779657dSKees Cook	    assignment or function argument
6598779657dSKees Cook	  - local variable is an array (or union containing an array),
6608779657dSKees Cook	    regardless of array type or length
6618779657dSKees Cook	  - uses register local variables
6628779657dSKees Cook
6638779657dSKees Cook	  This feature requires gcc version 4.9 or above, or a distribution
6648779657dSKees Cook	  gcc with the feature backported ("-fstack-protector-strong").
6658779657dSKees Cook
6668779657dSKees Cook	  On an x86 "defconfig" build, this feature adds canary checks to
6678779657dSKees Cook	  about 20% of all kernel functions, which increases the kernel code
6688779657dSKees Cook	  size by about 2%.
6698779657dSKees Cook
670d08b9f0cSSami Tolvanenconfig ARCH_SUPPORTS_SHADOW_CALL_STACK
671d08b9f0cSSami Tolvanen	bool
672d08b9f0cSSami Tolvanen	help
673afcf5441SDan Li	  An architecture should select this if it supports the compiler's
674afcf5441SDan Li	  Shadow Call Stack and implements runtime support for shadow stack
675aa7a65aeSWill Deacon	  switching.
676d08b9f0cSSami Tolvanen
677d08b9f0cSSami Tolvanenconfig SHADOW_CALL_STACK
678afcf5441SDan Li	bool "Shadow Call Stack"
679afcf5441SDan Li	depends on ARCH_SUPPORTS_SHADOW_CALL_STACK
68038792972SArd Biesheuvel	depends on DYNAMIC_FTRACE_WITH_ARGS || DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER
681d08b9f0cSSami Tolvanen	help
682afcf5441SDan Li	  This option enables the compiler's Shadow Call Stack, which
683afcf5441SDan Li	  uses a shadow stack to protect function return addresses from
684afcf5441SDan Li	  being overwritten by an attacker. More information can be found
685afcf5441SDan Li	  in the compiler's documentation:
686d08b9f0cSSami Tolvanen
687afcf5441SDan Li	  - Clang: https://clang.llvm.org/docs/ShadowCallStack.html
688afcf5441SDan Li	  - GCC: https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options
689d08b9f0cSSami Tolvanen
690d08b9f0cSSami Tolvanen	  Note that security guarantees in the kernel differ from the
691d08b9f0cSSami Tolvanen	  ones documented for user space. The kernel must store addresses
692d08b9f0cSSami Tolvanen	  of shadow stacks in memory, which means an attacker capable of
693d08b9f0cSSami Tolvanen	  reading and writing arbitrary memory may be able to locate them
694d08b9f0cSSami Tolvanen	  and hijack control flow by modifying the stacks.
695d08b9f0cSSami Tolvanen
6969beccca0SArd Biesheuvelconfig DYNAMIC_SCS
6979beccca0SArd Biesheuvel	bool
6989beccca0SArd Biesheuvel	help
6999beccca0SArd Biesheuvel	  Set by the arch code if it relies on code patching to insert the
7009beccca0SArd Biesheuvel	  shadow call stack push and pop instructions rather than on the
7019beccca0SArd Biesheuvel	  compiler.
7029beccca0SArd Biesheuvel
703dc5723b0SSami Tolvanenconfig LTO
704dc5723b0SSami Tolvanen	bool
705dc5723b0SSami Tolvanen	help
706dc5723b0SSami Tolvanen	  Selected if the kernel will be built using the compiler's LTO feature.
707dc5723b0SSami Tolvanen
708dc5723b0SSami Tolvanenconfig LTO_CLANG
709dc5723b0SSami Tolvanen	bool
710dc5723b0SSami Tolvanen	select LTO
711dc5723b0SSami Tolvanen	help
712dc5723b0SSami Tolvanen	  Selected if the kernel will be built using Clang's LTO feature.
713dc5723b0SSami Tolvanen
714dc5723b0SSami Tolvanenconfig ARCH_SUPPORTS_LTO_CLANG
715dc5723b0SSami Tolvanen	bool
716dc5723b0SSami Tolvanen	help
717dc5723b0SSami Tolvanen	  An architecture should select this option if it supports:
718dc5723b0SSami Tolvanen	  - compiling with Clang,
719dc5723b0SSami Tolvanen	  - compiling inline assembly with Clang's integrated assembler,
720dc5723b0SSami Tolvanen	  - and linking with LLD.
721dc5723b0SSami Tolvanen
722dc5723b0SSami Tolvanenconfig ARCH_SUPPORTS_LTO_CLANG_THIN
723dc5723b0SSami Tolvanen	bool
724dc5723b0SSami Tolvanen	help
725dc5723b0SSami Tolvanen	  An architecture should select this option if it can support Clang's
726dc5723b0SSami Tolvanen	  ThinLTO mode.
727dc5723b0SSami Tolvanen
728dc5723b0SSami Tolvanenconfig HAS_LTO_CLANG
729dc5723b0SSami Tolvanen	def_bool y
7301e68a8afSNathan Chancellor	depends on CC_IS_CLANG && LD_IS_LLD && AS_IS_LLVM
731dc5723b0SSami Tolvanen	depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
732dc5723b0SSami Tolvanen	depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
733dc5723b0SSami Tolvanen	depends on ARCH_SUPPORTS_LTO_CLANG
734dc5723b0SSami Tolvanen	depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT
735*349fde59SJakob Koschel	# https://github.com/ClangBuiltLinux/linux/issues/1721
736*349fde59SJakob Koschel	depends on (!KASAN || KASAN_HW_TAGS || CLANG_VERSION >= 170000) || !DEBUG_INFO
737*349fde59SJakob Koschel	depends on (!KCOV || CLANG_VERSION >= 170000) || !DEBUG_INFO
738dc5723b0SSami Tolvanen	depends on !GCOV_KERNEL
739dc5723b0SSami Tolvanen	help
740dc5723b0SSami Tolvanen	  The compiler and Kconfig options support building with Clang's
741dc5723b0SSami Tolvanen	  LTO.
742dc5723b0SSami Tolvanen
743dc5723b0SSami Tolvanenchoice
744dc5723b0SSami Tolvanen	prompt "Link Time Optimization (LTO)"
745dc5723b0SSami Tolvanen	default LTO_NONE
746dc5723b0SSami Tolvanen	help
747dc5723b0SSami Tolvanen	  This option enables Link Time Optimization (LTO), which allows the
748dc5723b0SSami Tolvanen	  compiler to optimize binaries globally.
749dc5723b0SSami Tolvanen
750dc5723b0SSami Tolvanen	  If unsure, select LTO_NONE. Note that LTO is very resource-intensive
751dc5723b0SSami Tolvanen	  so it's disabled by default.
752dc5723b0SSami Tolvanen
753dc5723b0SSami Tolvanenconfig LTO_NONE
754dc5723b0SSami Tolvanen	bool "None"
755dc5723b0SSami Tolvanen	help
756dc5723b0SSami Tolvanen	  Build the kernel normally, without Link Time Optimization (LTO).
757dc5723b0SSami Tolvanen
758dc5723b0SSami Tolvanenconfig LTO_CLANG_FULL
759dc5723b0SSami Tolvanen	bool "Clang Full LTO (EXPERIMENTAL)"
760dc5723b0SSami Tolvanen	depends on HAS_LTO_CLANG
761dc5723b0SSami Tolvanen	depends on !COMPILE_TEST
762dc5723b0SSami Tolvanen	select LTO_CLANG
763dc5723b0SSami Tolvanen	help
764dc5723b0SSami Tolvanen	  This option enables Clang's full Link Time Optimization (LTO), which
765dc5723b0SSami Tolvanen	  allows the compiler to optimize the kernel globally. If you enable
766dc5723b0SSami Tolvanen	  this option, the compiler generates LLVM bitcode instead of ELF
767dc5723b0SSami Tolvanen	  object files, and the actual compilation from bitcode happens at
768dc5723b0SSami Tolvanen	  the LTO link step, which may take several minutes depending on the
769dc5723b0SSami Tolvanen	  kernel configuration. More information can be found from LLVM's
770dc5723b0SSami Tolvanen	  documentation:
771dc5723b0SSami Tolvanen
772dc5723b0SSami Tolvanen	    https://llvm.org/docs/LinkTimeOptimization.html
773dc5723b0SSami Tolvanen
774dc5723b0SSami Tolvanen	  During link time, this option can use a large amount of RAM, and
775dc5723b0SSami Tolvanen	  may take much longer than the ThinLTO option.
776dc5723b0SSami Tolvanen
777dc5723b0SSami Tolvanenconfig LTO_CLANG_THIN
778dc5723b0SSami Tolvanen	bool "Clang ThinLTO (EXPERIMENTAL)"
779dc5723b0SSami Tolvanen	depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN
780dc5723b0SSami Tolvanen	select LTO_CLANG
781dc5723b0SSami Tolvanen	help
782dc5723b0SSami Tolvanen	  This option enables Clang's ThinLTO, which allows for parallel
783dc5723b0SSami Tolvanen	  optimization and faster incremental compiles compared to the
784dc5723b0SSami Tolvanen	  CONFIG_LTO_CLANG_FULL option. More information can be found
785dc5723b0SSami Tolvanen	  from Clang's documentation:
786dc5723b0SSami Tolvanen
787dc5723b0SSami Tolvanen	    https://clang.llvm.org/docs/ThinLTO.html
788dc5723b0SSami Tolvanen
789dc5723b0SSami Tolvanen	  If unsure, say Y.
790dc5723b0SSami Tolvanenendchoice
791dc5723b0SSami Tolvanen
792cf68fffbSSami Tolvanenconfig ARCH_SUPPORTS_CFI_CLANG
793cf68fffbSSami Tolvanen	bool
794cf68fffbSSami Tolvanen	help
795cf68fffbSSami Tolvanen	  An architecture should select this option if it can support Clang's
796cf68fffbSSami Tolvanen	  Control-Flow Integrity (CFI) checking.
797cf68fffbSSami Tolvanen
79889245600SSami Tolvanenconfig ARCH_USES_CFI_TRAPS
79989245600SSami Tolvanen	bool
80089245600SSami Tolvanen
801cf68fffbSSami Tolvanenconfig CFI_CLANG
802cf68fffbSSami Tolvanen	bool "Use Clang's Control Flow Integrity (CFI)"
80389245600SSami Tolvanen	depends on ARCH_SUPPORTS_CFI_CLANG
80489245600SSami Tolvanen	depends on $(cc-option,-fsanitize=kcfi)
805cf68fffbSSami Tolvanen	help
806cf68fffbSSami Tolvanen	  This option enables Clang’s forward-edge Control Flow Integrity
807cf68fffbSSami Tolvanen	  (CFI) checking, where the compiler injects a runtime check to each
808cf68fffbSSami Tolvanen	  indirect function call to ensure the target is a valid function with
809cf68fffbSSami Tolvanen	  the correct static type. This restricts possible call targets and
810cf68fffbSSami Tolvanen	  makes it more difficult for an attacker to exploit bugs that allow
811cf68fffbSSami Tolvanen	  the modification of stored function pointers. More information can be
812cf68fffbSSami Tolvanen	  found from Clang's documentation:
813cf68fffbSSami Tolvanen
814cf68fffbSSami Tolvanen	    https://clang.llvm.org/docs/ControlFlowIntegrity.html
815cf68fffbSSami Tolvanen
816cf68fffbSSami Tolvanenconfig CFI_PERMISSIVE
817cf68fffbSSami Tolvanen	bool "Use CFI in permissive mode"
818cf68fffbSSami Tolvanen	depends on CFI_CLANG
819cf68fffbSSami Tolvanen	help
820cf68fffbSSami Tolvanen	  When selected, Control Flow Integrity (CFI) violations result in a
821cf68fffbSSami Tolvanen	  warning instead of a kernel panic. This option should only be used
822cf68fffbSSami Tolvanen	  for finding indirect call type mismatches during development.
823cf68fffbSSami Tolvanen
824cf68fffbSSami Tolvanen	  If unsure, say N.
825cf68fffbSSami Tolvanen
8260f60a8efSKees Cookconfig HAVE_ARCH_WITHIN_STACK_FRAMES
8270f60a8efSKees Cook	bool
8280f60a8efSKees Cook	help
8290f60a8efSKees Cook	  An architecture should select this if it can walk the kernel stack
8300f60a8efSKees Cook	  frames to determine if an object is part of either the arguments
8310f60a8efSKees Cook	  or local variables (i.e. that it excludes saved return addresses,
8320f60a8efSKees Cook	  and similar) by implementing an inline arch_within_stack_frames(),
8330f60a8efSKees Cook	  which is used by CONFIG_HARDENED_USERCOPY.
8340f60a8efSKees Cook
83524a9c541SFrederic Weisbeckerconfig HAVE_CONTEXT_TRACKING_USER
8362b1d5024SFrederic Weisbecker	bool
8372b1d5024SFrederic Weisbecker	help
83891d1aa43SFrederic Weisbecker	  Provide kernel/user boundaries probes necessary for subsystems
83991d1aa43SFrederic Weisbecker	  that need it, such as userspace RCU extended quiescent state.
840490f561bSFrederic Weisbecker	  Syscalls need to be wrapped inside user_exit()-user_enter(), either
841490f561bSFrederic Weisbecker	  optimized behind static key or through the slow path using TIF_NOHZ
842490f561bSFrederic Weisbecker	  flag. Exceptions handlers must be wrapped as well. Irqs are already
8436f0e6c15SFrederic Weisbecker	  protected inside ct_irq_enter/ct_irq_exit() but preemption or signal
844490f561bSFrederic Weisbecker	  handling on irq exit still need to be protected.
845490f561bSFrederic Weisbecker
84624a9c541SFrederic Weisbeckerconfig HAVE_CONTEXT_TRACKING_USER_OFFSTACK
84783c2da2eSFrederic Weisbecker	bool
84883c2da2eSFrederic Weisbecker	help
84983c2da2eSFrederic Weisbecker	  Architecture neither relies on exception_enter()/exception_exit()
85083c2da2eSFrederic Weisbecker	  nor on schedule_user(). Also preempt_schedule_notrace() and
85183c2da2eSFrederic Weisbecker	  preempt_schedule_irq() can't be called in a preemptible section
85283c2da2eSFrederic Weisbecker	  while context tracking is CONTEXT_USER. This feature reflects a sane
85383c2da2eSFrederic Weisbecker	  entry implementation where the following requirements are met on
85483c2da2eSFrederic Weisbecker	  critical entry code, ie: before user_exit() or after user_enter():
85583c2da2eSFrederic Weisbecker
85683c2da2eSFrederic Weisbecker	  - Critical entry code isn't preemptible (or better yet:
85783c2da2eSFrederic Weisbecker	    not interruptible).
858493c1822SFrederic Weisbecker	  - No use of RCU read side critical sections, unless ct_nmi_enter()
85983c2da2eSFrederic Weisbecker	    got called.
86083c2da2eSFrederic Weisbecker	  - No use of instrumentation, unless instrumentation_begin() got
86183c2da2eSFrederic Weisbecker	    called.
86283c2da2eSFrederic Weisbecker
863490f561bSFrederic Weisbeckerconfig HAVE_TIF_NOHZ
864490f561bSFrederic Weisbecker	bool
865490f561bSFrederic Weisbecker	help
866490f561bSFrederic Weisbecker	  Arch relies on TIF_NOHZ and syscall slow path to implement context
867490f561bSFrederic Weisbecker	  tracking calls to user_enter()/user_exit().
8682b1d5024SFrederic Weisbecker
869b952741cSFrederic Weisbeckerconfig HAVE_VIRT_CPU_ACCOUNTING
870b952741cSFrederic Weisbecker	bool
871b952741cSFrederic Weisbecker
8722b91ec9fSFrederic Weisbeckerconfig HAVE_VIRT_CPU_ACCOUNTING_IDLE
8732b91ec9fSFrederic Weisbecker	bool
8742b91ec9fSFrederic Weisbecker	help
8752b91ec9fSFrederic Weisbecker	  Architecture has its own way to account idle CPU time and therefore
8762b91ec9fSFrederic Weisbecker	  doesn't implement vtime_account_idle().
8772b91ec9fSFrederic Weisbecker
87840565b5aSStanislaw Gruszkaconfig ARCH_HAS_SCALED_CPUTIME
87940565b5aSStanislaw Gruszka	bool
88040565b5aSStanislaw Gruszka
881554b0004SKevin Hilmanconfig HAVE_VIRT_CPU_ACCOUNTING_GEN
882554b0004SKevin Hilman	bool
883554b0004SKevin Hilman	default y if 64BIT
884554b0004SKevin Hilman	help
885554b0004SKevin Hilman	  With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
886554b0004SKevin Hilman	  Before enabling this option, arch code must be audited
887554b0004SKevin Hilman	  to ensure there are no races in concurrent read/write of
888554b0004SKevin Hilman	  cputime_t. For example, reading/writing 64-bit cputime_t on
889554b0004SKevin Hilman	  some 32-bit arches may require multiple accesses, so proper
890554b0004SKevin Hilman	  locking is needed to protect against concurrent accesses.
891554b0004SKevin Hilman
892fdf9c356SFrederic Weisbeckerconfig HAVE_IRQ_TIME_ACCOUNTING
893fdf9c356SFrederic Weisbecker	bool
894fdf9c356SFrederic Weisbecker	help
895fdf9c356SFrederic Weisbecker	  Archs need to ensure they use a high enough resolution clock to
896fdf9c356SFrederic Weisbecker	  support irq time accounting and then call enable_sched_clock_irqtime().
897fdf9c356SFrederic Weisbecker
898c49dd340SKalesh Singhconfig HAVE_MOVE_PUD
899c49dd340SKalesh Singh	bool
900c49dd340SKalesh Singh	help
901c49dd340SKalesh Singh	  Architectures that select this are able to move page tables at the
902c49dd340SKalesh Singh	  PUD level. If there are only 3 page table levels, the move effectively
903c49dd340SKalesh Singh	  happens at the PGD level.
904c49dd340SKalesh Singh
9052c91bd4aSJoel Fernandes (Google)config HAVE_MOVE_PMD
9062c91bd4aSJoel Fernandes (Google)	bool
9072c91bd4aSJoel Fernandes (Google)	help
9082c91bd4aSJoel Fernandes (Google)	  Archs that select this are able to move page tables at the PMD level.
9092c91bd4aSJoel Fernandes (Google)
91015626062SGerald Schaeferconfig HAVE_ARCH_TRANSPARENT_HUGEPAGE
91115626062SGerald Schaefer	bool
91215626062SGerald Schaefer
913a00cc7d9SMatthew Wilcoxconfig HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
914a00cc7d9SMatthew Wilcox	bool
915a00cc7d9SMatthew Wilcox
9160ddab1d2SToshi Kaniconfig HAVE_ARCH_HUGE_VMAP
9170ddab1d2SToshi Kani	bool
9180ddab1d2SToshi Kani
919121e6f32SNicholas Piggin#
920121e6f32SNicholas Piggin#  Archs that select this would be capable of PMD-sized vmaps (i.e.,
921559089e0SSong Liu#  arch_vmap_pmd_supported() returns true). The VM_ALLOW_HUGE_VMAP flag
922559089e0SSong Liu#  must be used to enable allocations to use hugepages.
923121e6f32SNicholas Piggin#
924121e6f32SNicholas Pigginconfig HAVE_ARCH_HUGE_VMALLOC
925121e6f32SNicholas Piggin	depends on HAVE_ARCH_HUGE_VMAP
926121e6f32SNicholas Piggin	bool
927121e6f32SNicholas Piggin
9283876d4a3SAlexandre Ghiticonfig ARCH_WANT_HUGE_PMD_SHARE
9293876d4a3SAlexandre Ghiti	bool
9303876d4a3SAlexandre Ghiti
9310f8975ecSPavel Emelyanovconfig HAVE_ARCH_SOFT_DIRTY
9320f8975ecSPavel Emelyanov	bool
9330f8975ecSPavel Emelyanov
934786d35d4SDavid Howellsconfig HAVE_MOD_ARCH_SPECIFIC
935786d35d4SDavid Howells	bool
936786d35d4SDavid Howells	help
937786d35d4SDavid Howells	  The arch uses struct mod_arch_specific to store data.  Many arches
938786d35d4SDavid Howells	  just need a simple module loader without arch specific data - those
939786d35d4SDavid Howells	  should not enable this.
940786d35d4SDavid Howells
941786d35d4SDavid Howellsconfig MODULES_USE_ELF_RELA
942786d35d4SDavid Howells	bool
943786d35d4SDavid Howells	help
944786d35d4SDavid Howells	  Modules only use ELF RELA relocations.  Modules with ELF REL
945786d35d4SDavid Howells	  relocations will give an error.
946786d35d4SDavid Howells
947786d35d4SDavid Howellsconfig MODULES_USE_ELF_REL
948786d35d4SDavid Howells	bool
949786d35d4SDavid Howells	help
950786d35d4SDavid Howells	  Modules only use ELF REL relocations.  Modules with ELF RELA
951786d35d4SDavid Howells	  relocations will give an error.
952786d35d4SDavid Howells
95301dc0386SChristophe Leroyconfig ARCH_WANTS_MODULES_DATA_IN_VMALLOC
95401dc0386SChristophe Leroy	bool
95501dc0386SChristophe Leroy	help
95601dc0386SChristophe Leroy	  For architectures like powerpc/32 which have constraints on module
95701dc0386SChristophe Leroy	  allocation and need to allocate module data outside of module area.
95801dc0386SChristophe Leroy
959cc1f0274SFrederic Weisbeckerconfig HAVE_IRQ_EXIT_ON_IRQ_STACK
960cc1f0274SFrederic Weisbecker	bool
961cc1f0274SFrederic Weisbecker	help
962cc1f0274SFrederic Weisbecker	  Architecture doesn't only execute the irq handler on the irq stack
963cc1f0274SFrederic Weisbecker	  but also irq_exit(). This way we can process softirqs on this irq
964cc1f0274SFrederic Weisbecker	  stack instead of switching to a new one when we call __do_softirq()
965cc1f0274SFrederic Weisbecker	  in the end of an hardirq.
966cc1f0274SFrederic Weisbecker	  This spares a stack switch and improves cache usage on softirq
967cc1f0274SFrederic Weisbecker	  processing.
968cc1f0274SFrederic Weisbecker
969cd1a41ceSThomas Gleixnerconfig HAVE_SOFTIRQ_ON_OWN_STACK
970cd1a41ceSThomas Gleixner	bool
971cd1a41ceSThomas Gleixner	help
972cd1a41ceSThomas Gleixner	  Architecture provides a function to run __do_softirq() on a
973c226bc3cSColin Ian King	  separate stack.
974cd1a41ceSThomas Gleixner
9758cbb2b50SSebastian Andrzej Siewiorconfig SOFTIRQ_ON_OWN_STACK
9768cbb2b50SSebastian Andrzej Siewior	def_bool HAVE_SOFTIRQ_ON_OWN_STACK && !PREEMPT_RT
9778cbb2b50SSebastian Andrzej Siewior
97812700c17SArnd Bergmannconfig ALTERNATE_USER_ADDRESS_SPACE
97912700c17SArnd Bergmann	bool
98012700c17SArnd Bergmann	help
98112700c17SArnd Bergmann	  Architectures set this when the CPU uses separate address
98212700c17SArnd Bergmann	  spaces for kernel and user space pointers. In this case, the
98312700c17SArnd Bergmann	  access_ok() check on a __user pointer is skipped.
98412700c17SArnd Bergmann
985235a8f02SKirill A. Shutemovconfig PGTABLE_LEVELS
986235a8f02SKirill A. Shutemov	int
987235a8f02SKirill A. Shutemov	default 2
988235a8f02SKirill A. Shutemov
9892b68f6caSKees Cookconfig ARCH_HAS_ELF_RANDOMIZE
9902b68f6caSKees Cook	bool
9912b68f6caSKees Cook	help
9922b68f6caSKees Cook	  An architecture supports choosing randomized locations for
9932b68f6caSKees Cook	  stack, mmap, brk, and ET_DYN. Defined functions:
9942b68f6caSKees Cook	  - arch_mmap_rnd()
995204db6edSKees Cook	  - arch_randomize_brk()
9962b68f6caSKees Cook
997d07e2259SDaniel Cashmanconfig HAVE_ARCH_MMAP_RND_BITS
998d07e2259SDaniel Cashman	bool
999d07e2259SDaniel Cashman	help
1000d07e2259SDaniel Cashman	  An arch should select this symbol if it supports setting a variable
1001d07e2259SDaniel Cashman	  number of bits for use in establishing the base address for mmap
1002d07e2259SDaniel Cashman	  allocations, has MMU enabled and provides values for both:
1003d07e2259SDaniel Cashman	  - ARCH_MMAP_RND_BITS_MIN
1004d07e2259SDaniel Cashman	  - ARCH_MMAP_RND_BITS_MAX
1005d07e2259SDaniel Cashman
10065f56a5dfSJiri Slabyconfig HAVE_EXIT_THREAD
10075f56a5dfSJiri Slaby	bool
10085f56a5dfSJiri Slaby	help
10095f56a5dfSJiri Slaby	  An architecture implements exit_thread.
10105f56a5dfSJiri Slaby
1011d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN
1012d07e2259SDaniel Cashman	int
1013d07e2259SDaniel Cashman
1014d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX
1015d07e2259SDaniel Cashman	int
1016d07e2259SDaniel Cashman
1017d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS_DEFAULT
1018d07e2259SDaniel Cashman	int
1019d07e2259SDaniel Cashman
1020d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS
1021d07e2259SDaniel Cashman	int "Number of bits to use for ASLR of mmap base address" if EXPERT
1022d07e2259SDaniel Cashman	range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
1023d07e2259SDaniel Cashman	default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
1024d07e2259SDaniel Cashman	default ARCH_MMAP_RND_BITS_MIN
1025d07e2259SDaniel Cashman	depends on HAVE_ARCH_MMAP_RND_BITS
1026d07e2259SDaniel Cashman	help
1027d07e2259SDaniel Cashman	  This value can be used to select the number of bits to use to
1028d07e2259SDaniel Cashman	  determine the random offset to the base address of vma regions
1029d07e2259SDaniel Cashman	  resulting from mmap allocations. This value will be bounded
1030d07e2259SDaniel Cashman	  by the architecture's minimum and maximum supported values.
1031d07e2259SDaniel Cashman
1032d07e2259SDaniel Cashman	  This value can be changed after boot using the
1033d07e2259SDaniel Cashman	  /proc/sys/vm/mmap_rnd_bits tunable
1034d07e2259SDaniel Cashman
1035d07e2259SDaniel Cashmanconfig HAVE_ARCH_MMAP_RND_COMPAT_BITS
1036d07e2259SDaniel Cashman	bool
1037d07e2259SDaniel Cashman	help
1038d07e2259SDaniel Cashman	  An arch should select this symbol if it supports running applications
1039d07e2259SDaniel Cashman	  in compatibility mode, supports setting a variable number of bits for
1040d07e2259SDaniel Cashman	  use in establishing the base address for mmap allocations, has MMU
1041d07e2259SDaniel Cashman	  enabled and provides values for both:
1042d07e2259SDaniel Cashman	  - ARCH_MMAP_RND_COMPAT_BITS_MIN
1043d07e2259SDaniel Cashman	  - ARCH_MMAP_RND_COMPAT_BITS_MAX
1044d07e2259SDaniel Cashman
1045d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN
1046d07e2259SDaniel Cashman	int
1047d07e2259SDaniel Cashman
1048d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX
1049d07e2259SDaniel Cashman	int
1050d07e2259SDaniel Cashman
1051d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1052d07e2259SDaniel Cashman	int
1053d07e2259SDaniel Cashman
1054d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS
1055d07e2259SDaniel Cashman	int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
1056d07e2259SDaniel Cashman	range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
1057d07e2259SDaniel Cashman	default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1058d07e2259SDaniel Cashman	default ARCH_MMAP_RND_COMPAT_BITS_MIN
1059d07e2259SDaniel Cashman	depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
1060d07e2259SDaniel Cashman	help
1061d07e2259SDaniel Cashman	  This value can be used to select the number of bits to use to
1062d07e2259SDaniel Cashman	  determine the random offset to the base address of vma regions
1063d07e2259SDaniel Cashman	  resulting from mmap allocations for compatible applications This
1064d07e2259SDaniel Cashman	  value will be bounded by the architecture's minimum and maximum
1065d07e2259SDaniel Cashman	  supported values.
1066d07e2259SDaniel Cashman
1067d07e2259SDaniel Cashman	  This value can be changed after boot using the
1068d07e2259SDaniel Cashman	  /proc/sys/vm/mmap_rnd_compat_bits tunable
1069d07e2259SDaniel Cashman
10701b028f78SDmitry Safonovconfig HAVE_ARCH_COMPAT_MMAP_BASES
10711b028f78SDmitry Safonov	bool
10721b028f78SDmitry Safonov	help
10731b028f78SDmitry Safonov	  This allows 64bit applications to invoke 32-bit mmap() syscall
10741b028f78SDmitry Safonov	  and vice-versa 32-bit applications to call 64-bit mmap().
10751b028f78SDmitry Safonov	  Required for applications doing different bitness syscalls.
10761b028f78SDmitry Safonov
10771f0e290cSGuenter Roeckconfig PAGE_SIZE_LESS_THAN_64KB
10781f0e290cSGuenter Roeck	def_bool y
10791f0e290cSGuenter Roeck	depends on !ARM64_64K_PAGES
10801f0e290cSGuenter Roeck	depends on !IA64_PAGE_SIZE_64KB
10811f0e290cSGuenter Roeck	depends on !PAGE_SIZE_64KB
10821f0e290cSGuenter Roeck	depends on !PARISC_PAGE_SIZE_64KB
1083e4bbd20dSNathan Chancellor	depends on PAGE_SIZE_LESS_THAN_256KB
1084e4bbd20dSNathan Chancellor
1085e4bbd20dSNathan Chancellorconfig PAGE_SIZE_LESS_THAN_256KB
1086e4bbd20dSNathan Chancellor	def_bool y
10871f0e290cSGuenter Roeck	depends on !PAGE_SIZE_256KB
10881f0e290cSGuenter Roeck
108967f3977fSAlexandre Ghiti# This allows to use a set of generic functions to determine mmap base
109067f3977fSAlexandre Ghiti# address by giving priority to top-down scheme only if the process
109167f3977fSAlexandre Ghiti# is not in legacy mode (compat task, unlimited stack size or
109267f3977fSAlexandre Ghiti# sysctl_legacy_va_layout).
109367f3977fSAlexandre Ghiti# Architecture that selects this option can provide its own version of:
109467f3977fSAlexandre Ghiti# - STACK_RND_MASK
109567f3977fSAlexandre Ghiticonfig ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
109667f3977fSAlexandre Ghiti	bool
109767f3977fSAlexandre Ghiti	depends on MMU
1098e7142bf5SAlexandre Ghiti	select ARCH_HAS_ELF_RANDOMIZE
109967f3977fSAlexandre Ghiti
110003f16cd0SJosh Poimboeufconfig HAVE_OBJTOOL
110103f16cd0SJosh Poimboeuf	bool
110203f16cd0SJosh Poimboeuf
11034ab7674fSJosh Poimboeufconfig HAVE_JUMP_LABEL_HACK
11044ab7674fSJosh Poimboeuf	bool
11054ab7674fSJosh Poimboeuf
110622102f45SJosh Poimboeufconfig HAVE_NOINSTR_HACK
110722102f45SJosh Poimboeuf	bool
110822102f45SJosh Poimboeuf
1109489e355bSJosh Poimboeufconfig HAVE_NOINSTR_VALIDATION
1110489e355bSJosh Poimboeuf	bool
1111489e355bSJosh Poimboeuf
11125f3da8c0SJosh Poimboeufconfig HAVE_UACCESS_VALIDATION
11135f3da8c0SJosh Poimboeuf	bool
11145f3da8c0SJosh Poimboeuf	select OBJTOOL
11155f3da8c0SJosh Poimboeuf
1116b9ab5ebbSJosh Poimboeufconfig HAVE_STACK_VALIDATION
1117b9ab5ebbSJosh Poimboeuf	bool
1118b9ab5ebbSJosh Poimboeuf	help
111903f16cd0SJosh Poimboeuf	  Architecture supports objtool compile-time frame pointer rule
112003f16cd0SJosh Poimboeuf	  validation.
1121b9ab5ebbSJosh Poimboeuf
1122af085d90SJosh Poimboeufconfig HAVE_RELIABLE_STACKTRACE
1123af085d90SJosh Poimboeuf	bool
1124af085d90SJosh Poimboeuf	help
1125140d7e88SMiroslav Benes	  Architecture has either save_stack_trace_tsk_reliable() or
1126140d7e88SMiroslav Benes	  arch_stack_walk_reliable() function which only returns a stack trace
1127140d7e88SMiroslav Benes	  if it can guarantee the trace is reliable.
1128af085d90SJosh Poimboeuf
1129468a9428SGeorge Spelvinconfig HAVE_ARCH_HASH
1130468a9428SGeorge Spelvin	bool
1131468a9428SGeorge Spelvin	default n
1132468a9428SGeorge Spelvin	help
1133468a9428SGeorge Spelvin	  If this is set, the architecture provides an <asm/hash.h>
1134468a9428SGeorge Spelvin	  file which provides platform-specific implementations of some
1135468a9428SGeorge Spelvin	  functions in <linux/hash.h> or fs/namei.c.
1136468a9428SGeorge Spelvin
1137666047feSFinn Thainconfig HAVE_ARCH_NVRAM_OPS
1138666047feSFinn Thain	bool
1139666047feSFinn Thain
11403a495511SWilliam Breathitt Grayconfig ISA_BUS_API
11413a495511SWilliam Breathitt Gray	def_bool ISA
11423a495511SWilliam Breathitt Gray
1143d2125043SAl Viro#
1144d2125043SAl Viro# ABI hall of shame
1145d2125043SAl Viro#
1146d2125043SAl Viroconfig CLONE_BACKWARDS
1147d2125043SAl Viro	bool
1148d2125043SAl Viro	help
1149d2125043SAl Viro	  Architecture has tls passed as the 4th argument of clone(2),
1150d2125043SAl Viro	  not the 5th one.
1151d2125043SAl Viro
1152d2125043SAl Viroconfig CLONE_BACKWARDS2
1153d2125043SAl Viro	bool
1154d2125043SAl Viro	help
1155d2125043SAl Viro	  Architecture has the first two arguments of clone(2) swapped.
1156d2125043SAl Viro
1157dfa9771aSMichal Simekconfig CLONE_BACKWARDS3
1158dfa9771aSMichal Simek	bool
1159dfa9771aSMichal Simek	help
1160dfa9771aSMichal Simek	  Architecture has tls passed as the 3rd argument of clone(2),
1161dfa9771aSMichal Simek	  not the 5th one.
1162dfa9771aSMichal Simek
1163eaca6eaeSAl Viroconfig ODD_RT_SIGACTION
1164eaca6eaeSAl Viro	bool
1165eaca6eaeSAl Viro	help
1166eaca6eaeSAl Viro	  Architecture has unusual rt_sigaction(2) arguments
1167eaca6eaeSAl Viro
11680a0e8cdfSAl Viroconfig OLD_SIGSUSPEND
11690a0e8cdfSAl Viro	bool
11700a0e8cdfSAl Viro	help
11710a0e8cdfSAl Viro	  Architecture has old sigsuspend(2) syscall, of one-argument variety
11720a0e8cdfSAl Viro
11730a0e8cdfSAl Viroconfig OLD_SIGSUSPEND3
11740a0e8cdfSAl Viro	bool
11750a0e8cdfSAl Viro	help
11760a0e8cdfSAl Viro	  Even weirder antique ABI - three-argument sigsuspend(2)
11770a0e8cdfSAl Viro
1178495dfbf7SAl Viroconfig OLD_SIGACTION
1179495dfbf7SAl Viro	bool
1180495dfbf7SAl Viro	help
1181495dfbf7SAl Viro	  Architecture has old sigaction(2) syscall.  Nope, not the same
1182495dfbf7SAl Viro	  as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
1183495dfbf7SAl Viro	  but fairly different variant of sigaction(2), thanks to OSF/1
1184495dfbf7SAl Viro	  compatibility...
1185495dfbf7SAl Viro
1186495dfbf7SAl Viroconfig COMPAT_OLD_SIGACTION
1187495dfbf7SAl Viro	bool
1188495dfbf7SAl Viro
118917435e5fSDeepa Dinamaniconfig COMPAT_32BIT_TIME
1190942437c9SArnd Bergmann	bool "Provide system calls for 32-bit time_t"
1191942437c9SArnd Bergmann	default !64BIT || COMPAT
119217435e5fSDeepa Dinamani	help
119317435e5fSDeepa Dinamani	  This enables 32 bit time_t support in addition to 64 bit time_t support.
119417435e5fSDeepa Dinamani	  This is relevant on all 32-bit architectures, and 64-bit architectures
119517435e5fSDeepa Dinamani	  as part of compat syscall handling.
119617435e5fSDeepa Dinamani
119787a4c375SChristoph Hellwigconfig ARCH_NO_PREEMPT
119887a4c375SChristoph Hellwig	bool
119987a4c375SChristoph Hellwig
1200a50a3f4bSThomas Gleixnerconfig ARCH_SUPPORTS_RT
1201a50a3f4bSThomas Gleixner	bool
1202a50a3f4bSThomas Gleixner
1203fff7fb0bSZhaoxiu Zengconfig CPU_NO_EFFICIENT_FFS
1204fff7fb0bSZhaoxiu Zeng	def_bool n
1205fff7fb0bSZhaoxiu Zeng
1206ba14a194SAndy Lutomirskiconfig HAVE_ARCH_VMAP_STACK
1207ba14a194SAndy Lutomirski	def_bool n
1208ba14a194SAndy Lutomirski	help
1209ba14a194SAndy Lutomirski	  An arch should select this symbol if it can support kernel stacks
1210ba14a194SAndy Lutomirski	  in vmalloc space.  This means:
1211ba14a194SAndy Lutomirski
1212ba14a194SAndy Lutomirski	  - vmalloc space must be large enough to hold many kernel stacks.
1213ba14a194SAndy Lutomirski	    This may rule out many 32-bit architectures.
1214ba14a194SAndy Lutomirski
1215ba14a194SAndy Lutomirski	  - Stacks in vmalloc space need to work reliably.  For example, if
1216ba14a194SAndy Lutomirski	    vmap page tables are created on demand, either this mechanism
1217ba14a194SAndy Lutomirski	    needs to work while the stack points to a virtual address with
1218ba14a194SAndy Lutomirski	    unpopulated page tables or arch code (switch_to() and switch_mm(),
1219ba14a194SAndy Lutomirski	    most likely) needs to ensure that the stack's page table entries
1220ba14a194SAndy Lutomirski	    are populated before running on a possibly unpopulated stack.
1221ba14a194SAndy Lutomirski
1222ba14a194SAndy Lutomirski	  - If the stack overflows into a guard page, something reasonable
1223ba14a194SAndy Lutomirski	    should happen.  The definition of "reasonable" is flexible, but
1224ba14a194SAndy Lutomirski	    instantly rebooting without logging anything would be unfriendly.
1225ba14a194SAndy Lutomirski
1226ba14a194SAndy Lutomirskiconfig VMAP_STACK
1227ba14a194SAndy Lutomirski	default y
1228ba14a194SAndy Lutomirski	bool "Use a virtually-mapped stack"
1229eafb149eSDaniel Axtens	depends on HAVE_ARCH_VMAP_STACK
123038dd767dSAndrey Konovalov	depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC
1231a7f7f624SMasahiro Yamada	help
1232ba14a194SAndy Lutomirski	  Enable this if you want the use virtually-mapped kernel stacks
1233ba14a194SAndy Lutomirski	  with guard pages.  This causes kernel stack overflows to be
1234ba14a194SAndy Lutomirski	  caught immediately rather than causing difficult-to-diagnose
1235ba14a194SAndy Lutomirski	  corruption.
1236ba14a194SAndy Lutomirski
123738dd767dSAndrey Konovalov	  To use this with software KASAN modes, the architecture must support
123838dd767dSAndrey Konovalov	  backing virtual mappings with real shadow memory, and KASAN_VMALLOC
123938dd767dSAndrey Konovalov	  must be enabled.
1240ba14a194SAndy Lutomirski
124139218ff4SKees Cookconfig HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
124239218ff4SKees Cook	def_bool n
124339218ff4SKees Cook	help
124439218ff4SKees Cook	  An arch should select this symbol if it can support kernel stack
124539218ff4SKees Cook	  offset randomization with calls to add_random_kstack_offset()
124639218ff4SKees Cook	  during syscall entry and choose_random_kstack_offset() during
124739218ff4SKees Cook	  syscall exit. Careful removal of -fstack-protector-strong and
124839218ff4SKees Cook	  -fstack-protector should also be applied to the entry code and
124939218ff4SKees Cook	  closely examined, as the artificial stack bump looks like an array
125039218ff4SKees Cook	  to the compiler, so it will attempt to add canary checks regardless
125139218ff4SKees Cook	  of the static branch state.
125239218ff4SKees Cook
12538cb37a59SMarco Elverconfig RANDOMIZE_KSTACK_OFFSET
12548cb37a59SMarco Elver	bool "Support for randomizing kernel stack offset on syscall entry" if EXPERT
12558cb37a59SMarco Elver	default y
125639218ff4SKees Cook	depends on HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
1257efa90c11SMarco Elver	depends on INIT_STACK_NONE || !CC_IS_CLANG || CLANG_VERSION >= 140000
125839218ff4SKees Cook	help
125939218ff4SKees Cook	  The kernel stack offset can be randomized (after pt_regs) by
126039218ff4SKees Cook	  roughly 5 bits of entropy, frustrating memory corruption
126139218ff4SKees Cook	  attacks that depend on stack address determinism or
12628cb37a59SMarco Elver	  cross-syscall address exposures.
12638cb37a59SMarco Elver
12648cb37a59SMarco Elver	  The feature is controlled via the "randomize_kstack_offset=on/off"
12658cb37a59SMarco Elver	  kernel boot param, and if turned off has zero overhead due to its use
12668cb37a59SMarco Elver	  of static branches (see JUMP_LABEL).
12678cb37a59SMarco Elver
12688cb37a59SMarco Elver	  If unsure, say Y.
12698cb37a59SMarco Elver
12708cb37a59SMarco Elverconfig RANDOMIZE_KSTACK_OFFSET_DEFAULT
12718cb37a59SMarco Elver	bool "Default state of kernel stack offset randomization"
12728cb37a59SMarco Elver	depends on RANDOMIZE_KSTACK_OFFSET
12738cb37a59SMarco Elver	help
12748cb37a59SMarco Elver	  Kernel stack offset randomization is controlled by kernel boot param
12758cb37a59SMarco Elver	  "randomize_kstack_offset=on/off", and this config chooses the default
12768cb37a59SMarco Elver	  boot state.
127739218ff4SKees Cook
1278ad21fc4fSLaura Abbottconfig ARCH_OPTIONAL_KERNEL_RWX
1279ad21fc4fSLaura Abbott	def_bool n
1280ad21fc4fSLaura Abbott
1281ad21fc4fSLaura Abbottconfig ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1282ad21fc4fSLaura Abbott	def_bool n
1283ad21fc4fSLaura Abbott
1284ad21fc4fSLaura Abbottconfig ARCH_HAS_STRICT_KERNEL_RWX
1285ad21fc4fSLaura Abbott	def_bool n
1286ad21fc4fSLaura Abbott
12870f5bf6d0SLaura Abbottconfig STRICT_KERNEL_RWX
1288ad21fc4fSLaura Abbott	bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX
1289ad21fc4fSLaura Abbott	depends on ARCH_HAS_STRICT_KERNEL_RWX
1290ad21fc4fSLaura Abbott	default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1291ad21fc4fSLaura Abbott	help
1292ad21fc4fSLaura Abbott	  If this is set, kernel text and rodata memory will be made read-only,
1293ad21fc4fSLaura Abbott	  and non-text memory will be made non-executable. This provides
1294ad21fc4fSLaura Abbott	  protection against certain security exploits (e.g. executing the heap
1295ad21fc4fSLaura Abbott	  or modifying text)
1296ad21fc4fSLaura Abbott
1297ad21fc4fSLaura Abbott	  These features are considered standard security practice these days.
1298ad21fc4fSLaura Abbott	  You should say Y here in almost all cases.
1299ad21fc4fSLaura Abbott
1300ad21fc4fSLaura Abbottconfig ARCH_HAS_STRICT_MODULE_RWX
1301ad21fc4fSLaura Abbott	def_bool n
1302ad21fc4fSLaura Abbott
13030f5bf6d0SLaura Abbottconfig STRICT_MODULE_RWX
1304ad21fc4fSLaura Abbott	bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX
1305ad21fc4fSLaura Abbott	depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES
1306ad21fc4fSLaura Abbott	default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1307ad21fc4fSLaura Abbott	help
1308ad21fc4fSLaura Abbott	  If this is set, module text and rodata memory will be made read-only,
1309ad21fc4fSLaura Abbott	  and non-text memory will be made non-executable. This provides
1310ad21fc4fSLaura Abbott	  protection against certain security exploits (e.g. writing to text)
1311ad21fc4fSLaura Abbott
1312ea8c64acSChristoph Hellwig# select if the architecture provides an asm/dma-direct.h header
1313ea8c64acSChristoph Hellwigconfig ARCH_HAS_PHYS_TO_DMA
1314ea8c64acSChristoph Hellwig	bool
1315ea8c64acSChristoph Hellwig
131604f264d3SPaul Burtonconfig HAVE_ARCH_COMPILER_H
131704f264d3SPaul Burton	bool
131804f264d3SPaul Burton	help
131904f264d3SPaul Burton	  An architecture can select this if it provides an
132004f264d3SPaul Burton	  asm/compiler.h header that should be included after
132104f264d3SPaul Burton	  linux/compiler-*.h in order to override macro definitions that those
132204f264d3SPaul Burton	  headers generally provide.
132304f264d3SPaul Burton
1324271ca788SArd Biesheuvelconfig HAVE_ARCH_PREL32_RELOCATIONS
1325271ca788SArd Biesheuvel	bool
1326271ca788SArd Biesheuvel	help
1327271ca788SArd Biesheuvel	  May be selected by an architecture if it supports place-relative
1328271ca788SArd Biesheuvel	  32-bit relocations, both in the toolchain and in the module loader,
1329271ca788SArd Biesheuvel	  in which case relative references can be used in special sections
1330271ca788SArd Biesheuvel	  for PCI fixup, initcalls etc which are only half the size on 64 bit
1331271ca788SArd Biesheuvel	  architectures, and don't require runtime relocation on relocatable
1332271ca788SArd Biesheuvel	  kernels.
1333271ca788SArd Biesheuvel
1334ce9084baSArd Biesheuvelconfig ARCH_USE_MEMREMAP_PROT
1335ce9084baSArd Biesheuvel	bool
1336ce9084baSArd Biesheuvel
1337fb346fd9SWaiman Longconfig LOCK_EVENT_COUNTS
1338fb346fd9SWaiman Long	bool "Locking event counts collection"
1339fb346fd9SWaiman Long	depends on DEBUG_FS
1340a7f7f624SMasahiro Yamada	help
1341fb346fd9SWaiman Long	  Enable light-weight counting of various locking related events
1342fb346fd9SWaiman Long	  in the system with minimal performance impact. This reduces
1343fb346fd9SWaiman Long	  the chance of application behavior change because of timing
1344fb346fd9SWaiman Long	  differences. The counts are reported via debugfs.
1345fb346fd9SWaiman Long
13465cf896fbSPeter Collingbourne# Select if the architecture has support for applying RELR relocations.
13475cf896fbSPeter Collingbourneconfig ARCH_HAS_RELR
13485cf896fbSPeter Collingbourne	bool
13495cf896fbSPeter Collingbourne
13505cf896fbSPeter Collingbourneconfig RELR
13515cf896fbSPeter Collingbourne	bool "Use RELR relocation packing"
13525cf896fbSPeter Collingbourne	depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR
13535cf896fbSPeter Collingbourne	default y
13545cf896fbSPeter Collingbourne	help
13555cf896fbSPeter Collingbourne	  Store the kernel's dynamic relocations in the RELR relocation packing
13565cf896fbSPeter Collingbourne	  format. Requires a compatible linker (LLD supports this feature), as
13575cf896fbSPeter Collingbourne	  well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy
13585cf896fbSPeter Collingbourne	  are compatible).
13595cf896fbSPeter Collingbourne
13600c9c1d56SThiago Jung Bauermannconfig ARCH_HAS_MEM_ENCRYPT
13610c9c1d56SThiago Jung Bauermann	bool
13620c9c1d56SThiago Jung Bauermann
136346b49b12STom Lendackyconfig ARCH_HAS_CC_PLATFORM
136446b49b12STom Lendacky	bool
136546b49b12STom Lendacky
13660e242208SHassan Naveedconfig HAVE_SPARSE_SYSCALL_NR
13670e242208SHassan Naveed	bool
13680e242208SHassan Naveed	help
13690e242208SHassan Naveed	  An architecture should select this if its syscall numbering is sparse
13700e242208SHassan Naveed	  to save space. For example, MIPS architecture has a syscall array with
13710e242208SHassan Naveed	  entries at 4000, 5000 and 6000 locations. This option turns on syscall
13720e242208SHassan Naveed	  related optimizations for a given architecture.
13730e242208SHassan Naveed
1374d60d7de3SSven Schnelleconfig ARCH_HAS_VDSO_DATA
1375d60d7de3SSven Schnelle	bool
1376d60d7de3SSven Schnelle
1377115284d8SJosh Poimboeufconfig HAVE_STATIC_CALL
1378115284d8SJosh Poimboeuf	bool
1379115284d8SJosh Poimboeuf
13809183c3f9SJosh Poimboeufconfig HAVE_STATIC_CALL_INLINE
13819183c3f9SJosh Poimboeuf	bool
13829183c3f9SJosh Poimboeuf	depends on HAVE_STATIC_CALL
138303f16cd0SJosh Poimboeuf	select OBJTOOL
13849183c3f9SJosh Poimboeuf
13856ef869e0SMichal Hockoconfig HAVE_PREEMPT_DYNAMIC
13866ef869e0SMichal Hocko	bool
138799cf983cSMark Rutland
138899cf983cSMark Rutlandconfig HAVE_PREEMPT_DYNAMIC_CALL
138999cf983cSMark Rutland	bool
13906ef869e0SMichal Hocko	depends on HAVE_STATIC_CALL
139199cf983cSMark Rutland	select HAVE_PREEMPT_DYNAMIC
13926ef869e0SMichal Hocko	help
139399cf983cSMark Rutland	  An architecture should select this if it can handle the preemption
139499cf983cSMark Rutland	  model being selected at boot time using static calls.
139599cf983cSMark Rutland
139699cf983cSMark Rutland	  Where an architecture selects HAVE_STATIC_CALL_INLINE, any call to a
139799cf983cSMark Rutland	  preemption function will be patched directly.
139899cf983cSMark Rutland
139999cf983cSMark Rutland	  Where an architecture does not select HAVE_STATIC_CALL_INLINE, any
140099cf983cSMark Rutland	  call to a preemption function will go through a trampoline, and the
140199cf983cSMark Rutland	  trampoline will be patched.
140299cf983cSMark Rutland
140399cf983cSMark Rutland	  It is strongly advised to support inline static call to avoid any
140499cf983cSMark Rutland	  overhead.
140599cf983cSMark Rutland
140699cf983cSMark Rutlandconfig HAVE_PREEMPT_DYNAMIC_KEY
140799cf983cSMark Rutland	bool
1408a0a12c3eSNick Desaulniers	depends on HAVE_ARCH_JUMP_LABEL
140999cf983cSMark Rutland	select HAVE_PREEMPT_DYNAMIC
141099cf983cSMark Rutland	help
141199cf983cSMark Rutland	  An architecture should select this if it can handle the preemption
141299cf983cSMark Rutland	  model being selected at boot time using static keys.
141399cf983cSMark Rutland
141499cf983cSMark Rutland	  Each preemption function will be given an early return based on a
141599cf983cSMark Rutland	  static key. This should have slightly lower overhead than non-inline
141699cf983cSMark Rutland	  static calls, as this effectively inlines each trampoline into the
141799cf983cSMark Rutland	  start of its callee. This may avoid redundant work, and may
141899cf983cSMark Rutland	  integrate better with CFI schemes.
141999cf983cSMark Rutland
142099cf983cSMark Rutland	  This will have greater overhead than using inline static calls as
142199cf983cSMark Rutland	  the call to the preemption function cannot be entirely elided.
14226ef869e0SMichal Hocko
142359612b24SNathan Chancellorconfig ARCH_WANT_LD_ORPHAN_WARN
142459612b24SNathan Chancellor	bool
142559612b24SNathan Chancellor	help
142659612b24SNathan Chancellor	  An arch should select this symbol once all linker sections are explicitly
142759612b24SNathan Chancellor	  included, size-asserted, or discarded in the linker scripts. This is
142859612b24SNathan Chancellor	  important because we never want expected sections to be placed heuristically
142959612b24SNathan Chancellor	  by the linker, since the locations of such sections can change between linker
143059612b24SNathan Chancellor	  versions.
143159612b24SNathan Chancellor
14324f5b0c17SMike Rapoportconfig HAVE_ARCH_PFN_VALID
14334f5b0c17SMike Rapoport	bool
14344f5b0c17SMike Rapoport
14355d6ad668SMike Rapoportconfig ARCH_SUPPORTS_DEBUG_PAGEALLOC
14365d6ad668SMike Rapoport	bool
14375d6ad668SMike Rapoport
1438df4e817bSPasha Tatashinconfig ARCH_SUPPORTS_PAGE_TABLE_CHECK
1439df4e817bSPasha Tatashin	bool
1440df4e817bSPasha Tatashin
14412ca408d9SBrian Gerstconfig ARCH_SPLIT_ARG64
14422ca408d9SBrian Gerst	bool
14432ca408d9SBrian Gerst	help
14442ca408d9SBrian Gerst	  If a 32-bit architecture requires 64-bit arguments to be split into
14452ca408d9SBrian Gerst	  pairs of 32-bit arguments, select this option.
14462ca408d9SBrian Gerst
14477facdc42SAl Viroconfig ARCH_HAS_ELFCORE_COMPAT
14487facdc42SAl Viro	bool
14497facdc42SAl Viro
145058e106e7SBalbir Singhconfig ARCH_HAS_PARANOID_L1D_FLUSH
145158e106e7SBalbir Singh	bool
145258e106e7SBalbir Singh
1453d593d64fSPrasad Sodagudiconfig ARCH_HAVE_TRACE_MMIO_ACCESS
1454d593d64fSPrasad Sodagudi	bool
1455d593d64fSPrasad Sodagudi
14561bdda24cSThomas Gleixnerconfig DYNAMIC_SIGFRAME
14571bdda24cSThomas Gleixner	bool
14581bdda24cSThomas Gleixner
145950468e43SJarkko Sakkinen# Select, if arch has a named attribute group bound to NUMA device nodes.
146050468e43SJarkko Sakkinenconfig HAVE_ARCH_NODE_DEV_GROUP
146150468e43SJarkko Sakkinen	bool
146250468e43SJarkko Sakkinen
1463eed9a328SYu Zhaoconfig ARCH_HAS_NONLEAF_PMD_YOUNG
1464eed9a328SYu Zhao	bool
1465eed9a328SYu Zhao	help
1466eed9a328SYu Zhao	  Architectures that select this option are capable of setting the
1467eed9a328SYu Zhao	  accessed bit in non-leaf PMD entries when using them as part of linear
1468eed9a328SYu Zhao	  address translations. Page table walkers that clear the accessed bit
1469eed9a328SYu Zhao	  may use this capability to reduce their search space.
1470eed9a328SYu Zhao
14712521f2c2SPeter Oberparleitersource "kernel/gcov/Kconfig"
147245332b1bSMasahiro Yamada
147345332b1bSMasahiro Yamadasource "scripts/gcc-plugins/Kconfig"
1474fa1b5d09SLinus Torvalds
1475d49a0626SPeter Zijlstraconfig FUNCTION_ALIGNMENT_4B
1476d49a0626SPeter Zijlstra	bool
1477d49a0626SPeter Zijlstra
1478d49a0626SPeter Zijlstraconfig FUNCTION_ALIGNMENT_8B
1479d49a0626SPeter Zijlstra	bool
1480d49a0626SPeter Zijlstra
1481d49a0626SPeter Zijlstraconfig FUNCTION_ALIGNMENT_16B
1482d49a0626SPeter Zijlstra	bool
1483d49a0626SPeter Zijlstra
1484d49a0626SPeter Zijlstraconfig FUNCTION_ALIGNMENT_32B
1485d49a0626SPeter Zijlstra	bool
1486d49a0626SPeter Zijlstra
1487d49a0626SPeter Zijlstraconfig FUNCTION_ALIGNMENT_64B
1488d49a0626SPeter Zijlstra	bool
1489d49a0626SPeter Zijlstra
1490d49a0626SPeter Zijlstraconfig FUNCTION_ALIGNMENT
1491d49a0626SPeter Zijlstra	int
1492d49a0626SPeter Zijlstra	default 64 if FUNCTION_ALIGNMENT_64B
1493d49a0626SPeter Zijlstra	default 32 if FUNCTION_ALIGNMENT_32B
1494d49a0626SPeter Zijlstra	default 16 if FUNCTION_ALIGNMENT_16B
1495d49a0626SPeter Zijlstra	default 8 if FUNCTION_ALIGNMENT_8B
1496d49a0626SPeter Zijlstra	default 4 if FUNCTION_ALIGNMENT_4B
1497d49a0626SPeter Zijlstra	default 0
1498d49a0626SPeter Zijlstra
149922471e13SRandy Dunlapendmenu
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