1fb32e03fSMathieu Desnoyers# 2fb32e03fSMathieu Desnoyers# General architecture dependent options 3fb32e03fSMathieu Desnoyers# 4125e5645SMathieu Desnoyers 5125e5645SMathieu Desnoyersconfig OPROFILE 6b309a294SRobert Richter tristate "OProfile system profiling" 7125e5645SMathieu Desnoyers depends on PROFILING 8125e5645SMathieu Desnoyers depends on HAVE_OPROFILE 9d69d59f4SIngo Molnar select RING_BUFFER 109a5963ebSChristian Borntraeger select RING_BUFFER_ALLOW_SWAP 11125e5645SMathieu Desnoyers help 12125e5645SMathieu Desnoyers OProfile is a profiling system capable of profiling the 13125e5645SMathieu Desnoyers whole system, include the kernel, kernel modules, libraries, 14125e5645SMathieu Desnoyers and applications. 15125e5645SMathieu Desnoyers 16125e5645SMathieu Desnoyers If unsure, say N. 17125e5645SMathieu Desnoyers 184d4036e0SJason Yehconfig OPROFILE_EVENT_MULTIPLEX 194d4036e0SJason Yeh bool "OProfile multiplexing support (EXPERIMENTAL)" 204d4036e0SJason Yeh default n 214d4036e0SJason Yeh depends on OPROFILE && X86 224d4036e0SJason Yeh help 234d4036e0SJason Yeh The number of hardware counters is limited. The multiplexing 244d4036e0SJason Yeh feature enables OProfile to gather more events than counters 254d4036e0SJason Yeh are provided by the hardware. This is realized by switching 264d4036e0SJason Yeh between events at an user specified time interval. 274d4036e0SJason Yeh 284d4036e0SJason Yeh If unsure, say N. 294d4036e0SJason Yeh 30125e5645SMathieu Desnoyersconfig HAVE_OPROFILE 319ba16087SJan Beulich bool 32125e5645SMathieu Desnoyers 33dcfce4a0SRobert Richterconfig OPROFILE_NMI_TIMER 34dcfce4a0SRobert Richter def_bool y 35dcfce4a0SRobert Richter depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI 36dcfce4a0SRobert Richter 37125e5645SMathieu Desnoyersconfig KPROBES 38125e5645SMathieu Desnoyers bool "Kprobes" 3905ed160eSMasami Hiramatsu depends on MODULES 40125e5645SMathieu Desnoyers depends on HAVE_KPROBES 4105ed160eSMasami Hiramatsu select KALLSYMS 42125e5645SMathieu Desnoyers help 43125e5645SMathieu Desnoyers Kprobes allows you to trap at almost any kernel address and 44125e5645SMathieu Desnoyers execute a callback function. register_kprobe() establishes 45125e5645SMathieu Desnoyers a probepoint and specifies the callback. Kprobes is useful 46125e5645SMathieu Desnoyers for kernel debugging, non-intrusive instrumentation and testing. 47125e5645SMathieu Desnoyers If in doubt, say "N". 48125e5645SMathieu Desnoyers 4945f81b1cSSteven Rostedtconfig JUMP_LABEL 50c5905afbSIngo Molnar bool "Optimize very unlikely/likely branches" 5145f81b1cSSteven Rostedt depends on HAVE_ARCH_JUMP_LABEL 5245f81b1cSSteven Rostedt help 53c5905afbSIngo Molnar This option enables a transparent branch optimization that 54c5905afbSIngo Molnar makes certain almost-always-true or almost-always-false branch 55c5905afbSIngo Molnar conditions even cheaper to execute within the kernel. 5645f81b1cSSteven Rostedt 57c5905afbSIngo Molnar Certain performance-sensitive kernel code, such as trace points, 58c5905afbSIngo Molnar scheduler functionality, networking code and KVM have such 59c5905afbSIngo Molnar branches and include support for this optimization technique. 60c5905afbSIngo Molnar 61c5905afbSIngo Molnar If it is detected that the compiler has support for "asm goto", 62c5905afbSIngo Molnar the kernel will compile such branches with just a nop 63c5905afbSIngo Molnar instruction. When the condition flag is toggled to true, the 64c5905afbSIngo Molnar nop will be converted to a jump instruction to execute the 65c5905afbSIngo Molnar conditional block of instructions. 66c5905afbSIngo Molnar 67c5905afbSIngo Molnar This technique lowers overhead and stress on the branch prediction 68c5905afbSIngo Molnar of the processor and generally makes the kernel faster. The update 69c5905afbSIngo Molnar of the condition is slower, but those are always very rare. 70c5905afbSIngo Molnar 71c5905afbSIngo Molnar ( On 32-bit x86, the necessary options added to the compiler 72c5905afbSIngo Molnar flags may increase the size of the kernel slightly. ) 7345f81b1cSSteven Rostedt 74afd66255SMasami Hiramatsuconfig OPTPROBES 755cc718b9SMasami Hiramatsu def_bool y 765cc718b9SMasami Hiramatsu depends on KPROBES && HAVE_OPTPROBES 77afd66255SMasami Hiramatsu depends on !PREEMPT 78afd66255SMasami Hiramatsu 792b144498SSrikar Dronamrajuconfig UPROBES 807b2d81d4SIngo Molnar bool "Transparent user-space probes (EXPERIMENTAL)" 81ec83db0fSSrikar Dronamraju depends on UPROBE_EVENT && PERF_EVENTS 822b144498SSrikar Dronamraju default n 832b144498SSrikar Dronamraju help 847b2d81d4SIngo Molnar Uprobes is the user-space counterpart to kprobes: they 857b2d81d4SIngo Molnar enable instrumentation applications (such as 'perf probe') 867b2d81d4SIngo Molnar to establish unintrusive probes in user-space binaries and 877b2d81d4SIngo Molnar libraries, by executing handler functions when the probes 887b2d81d4SIngo Molnar are hit by user-space applications. 897b2d81d4SIngo Molnar 907b2d81d4SIngo Molnar ( These probes come in the form of single-byte breakpoints, 917b2d81d4SIngo Molnar managed by the kernel and kept transparent to the probed 927b2d81d4SIngo Molnar application. ) 932b144498SSrikar Dronamraju 942b144498SSrikar Dronamraju If in doubt, say "N". 952b144498SSrikar Dronamraju 9658340a07SJohannes Bergconfig HAVE_EFFICIENT_UNALIGNED_ACCESS 979ba16087SJan Beulich bool 9858340a07SJohannes Berg help 9958340a07SJohannes Berg Some architectures are unable to perform unaligned accesses 10058340a07SJohannes Berg without the use of get_unaligned/put_unaligned. Others are 10158340a07SJohannes Berg unable to perform such accesses efficiently (e.g. trap on 10258340a07SJohannes Berg unaligned access and require fixing it up in the exception 10358340a07SJohannes Berg handler.) 10458340a07SJohannes Berg 10558340a07SJohannes Berg This symbol should be selected by an architecture if it can 10658340a07SJohannes Berg perform unaligned accesses efficiently to allow different 10758340a07SJohannes Berg code paths to be selected for these cases. Some network 10858340a07SJohannes Berg drivers, for example, could opt to not fix up alignment 10958340a07SJohannes Berg problems with received packets if doing so would not help 11058340a07SJohannes Berg much. 11158340a07SJohannes Berg 11258340a07SJohannes Berg See Documentation/unaligned-memory-access.txt for more 11358340a07SJohannes Berg information on the topic of unaligned memory accesses. 11458340a07SJohannes Berg 1151a94bc34SHeiko Carstensconfig HAVE_SYSCALL_WRAPPERS 1161a94bc34SHeiko Carstens bool 1171a94bc34SHeiko Carstens 1189edddaa2SAnanth N Mavinakayanahalliconfig KRETPROBES 1199edddaa2SAnanth N Mavinakayanahalli def_bool y 1209edddaa2SAnanth N Mavinakayanahalli depends on KPROBES && HAVE_KRETPROBES 1219edddaa2SAnanth N Mavinakayanahalli 1227c68af6eSAvi Kivityconfig USER_RETURN_NOTIFIER 1237c68af6eSAvi Kivity bool 1247c68af6eSAvi Kivity depends on HAVE_USER_RETURN_NOTIFIER 1257c68af6eSAvi Kivity help 1267c68af6eSAvi Kivity Provide a kernel-internal notification when a cpu is about to 1277c68af6eSAvi Kivity switch to user mode. 1287c68af6eSAvi Kivity 12928b2ee20SRik van Rielconfig HAVE_IOREMAP_PROT 1309ba16087SJan Beulich bool 13128b2ee20SRik van Riel 132125e5645SMathieu Desnoyersconfig HAVE_KPROBES 1339ba16087SJan Beulich bool 1349edddaa2SAnanth N Mavinakayanahalli 1359edddaa2SAnanth N Mavinakayanahalliconfig HAVE_KRETPROBES 1369ba16087SJan Beulich bool 13774bc7ceeSArthur Kepner 138afd66255SMasami Hiramatsuconfig HAVE_OPTPROBES 139afd66255SMasami Hiramatsu bool 140d314d74cSCong Wang 141d314d74cSCong Wangconfig HAVE_NMI_WATCHDOG 142d314d74cSCong Wang bool 1431f5a4ad9SRoland McGrath# 1441f5a4ad9SRoland McGrath# An arch should select this if it provides all these things: 1451f5a4ad9SRoland McGrath# 1461f5a4ad9SRoland McGrath# task_pt_regs() in asm/processor.h or asm/ptrace.h 1471f5a4ad9SRoland McGrath# arch_has_single_step() if there is hardware single-step support 1481f5a4ad9SRoland McGrath# arch_has_block_step() if there is hardware block-step support 1491f5a4ad9SRoland McGrath# asm/syscall.h supplying asm-generic/syscall.h interface 1501f5a4ad9SRoland McGrath# linux/regset.h user_regset interfaces 1511f5a4ad9SRoland McGrath# CORE_DUMP_USE_REGSET #define'd in linux/elf.h 1521f5a4ad9SRoland McGrath# TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} 1531f5a4ad9SRoland McGrath# TIF_NOTIFY_RESUME calls tracehook_notify_resume() 1541f5a4ad9SRoland McGrath# signal delivery calls tracehook_signal_handler() 1551f5a4ad9SRoland McGrath# 1561f5a4ad9SRoland McGrathconfig HAVE_ARCH_TRACEHOOK 1579ba16087SJan Beulich bool 1581f5a4ad9SRoland McGrath 15974bc7ceeSArthur Kepnerconfig HAVE_DMA_ATTRS 1609ba16087SJan Beulich bool 1613d442233SJens Axboe 162c64be2bbSMarek Szyprowskiconfig HAVE_DMA_CONTIGUOUS 163c64be2bbSMarek Szyprowski bool 164c64be2bbSMarek Szyprowski 1653d442233SJens Axboeconfig USE_GENERIC_SMP_HELPERS 1669ba16087SJan Beulich bool 1679483a578SDavid Brownell 16829d5e047SThomas Gleixnerconfig GENERIC_SMP_IDLE_THREAD 16929d5e047SThomas Gleixner bool 17029d5e047SThomas Gleixner 171a6359d1eSThomas Gleixner# Select if arch init_task initializer is different to init/init_task.c 172a6359d1eSThomas Gleixnerconfig ARCH_INIT_TASK 173a4a2eb49SThomas Gleixner bool 174a4a2eb49SThomas Gleixner 175f5e10287SThomas Gleixner# Select if arch has its private alloc_task_struct() function 176f5e10287SThomas Gleixnerconfig ARCH_TASK_STRUCT_ALLOCATOR 177f5e10287SThomas Gleixner bool 178f5e10287SThomas Gleixner 179f5e10287SThomas Gleixner# Select if arch has its private alloc_thread_info() function 180f5e10287SThomas Gleixnerconfig ARCH_THREAD_INFO_ALLOCATOR 181f5e10287SThomas Gleixner bool 182f5e10287SThomas Gleixner 183f850c30cSHeiko Carstensconfig HAVE_REGS_AND_STACK_ACCESS_API 184f850c30cSHeiko Carstens bool 185e01292b1SHeiko Carstens help 186e01292b1SHeiko Carstens This symbol should be selected by an architecure if it supports 187e01292b1SHeiko Carstens the API needed to access registers and stack entries from pt_regs, 188e01292b1SHeiko Carstens declared in asm/ptrace.h 189e01292b1SHeiko Carstens For example the kprobes-based event tracer needs this API. 190f850c30cSHeiko Carstens 1919483a578SDavid Brownellconfig HAVE_CLK 1929ba16087SJan Beulich bool 1939483a578SDavid Brownell help 1949483a578SDavid Brownell The <linux/clk.h> calls support software clock gating and 1959483a578SDavid Brownell thus are a key power management tool on many systems. 1969483a578SDavid Brownell 1975ee00bd4SJoerg Roedelconfig HAVE_DMA_API_DEBUG 1985ee00bd4SJoerg Roedel bool 19936cd3c9fSHeiko Carstens 20062a038d3SK.Prasadconfig HAVE_HW_BREAKPOINT 20162a038d3SK.Prasad bool 20299e8c5a3SFrederic Weisbecker depends on PERF_EVENTS 20362a038d3SK.Prasad 2040102752eSFrederic Weisbeckerconfig HAVE_MIXED_BREAKPOINTS_REGS 2050102752eSFrederic Weisbecker bool 2060102752eSFrederic Weisbecker depends on HAVE_HW_BREAKPOINT 2070102752eSFrederic Weisbecker help 2080102752eSFrederic Weisbecker Depending on the arch implementation of hardware breakpoints, 2090102752eSFrederic Weisbecker some of them have separate registers for data and instruction 2100102752eSFrederic Weisbecker breakpoints addresses, others have mixed registers to store 2110102752eSFrederic Weisbecker them but define the access type in a control register. 2120102752eSFrederic Weisbecker Select this option if your arch implements breakpoints under the 2130102752eSFrederic Weisbecker latter fashion. 2140102752eSFrederic Weisbecker 2157c68af6eSAvi Kivityconfig HAVE_USER_RETURN_NOTIFIER 2167c68af6eSAvi Kivity bool 217a1922ed6SIngo Molnar 218c01d4323SFrederic Weisbeckerconfig HAVE_PERF_EVENTS_NMI 219c01d4323SFrederic Weisbecker bool 22023637d47SFrederic Weisbecker help 22123637d47SFrederic Weisbecker System hardware can generate an NMI using the perf event 22223637d47SFrederic Weisbecker subsystem. Also has support for calculating CPU cycle events 22323637d47SFrederic Weisbecker to determine how many clock cycles in a given period. 224c01d4323SFrederic Weisbecker 225bf5438fcSJason Baronconfig HAVE_ARCH_JUMP_LABEL 226bf5438fcSJason Baron bool 227bf5438fcSJason Baron 228335d7afbSGerald Schaeferconfig HAVE_ARCH_MUTEX_CPU_RELAX 229335d7afbSGerald Schaefer bool 230335d7afbSGerald Schaefer 23126723911SPeter Zijlstraconfig HAVE_RCU_TABLE_FREE 23226723911SPeter Zijlstra bool 23326723911SPeter Zijlstra 234df013ffbSHuang Yingconfig ARCH_HAVE_NMI_SAFE_CMPXCHG 235df013ffbSHuang Ying bool 236df013ffbSHuang Ying 23743570fd2SHeiko Carstensconfig HAVE_ALIGNED_STRUCT_PAGE 23843570fd2SHeiko Carstens bool 23943570fd2SHeiko Carstens help 24043570fd2SHeiko Carstens This makes sure that struct pages are double word aligned and that 24143570fd2SHeiko Carstens e.g. the SLUB allocator can perform double word atomic operations 24243570fd2SHeiko Carstens on a struct page for better performance. However selecting this 24343570fd2SHeiko Carstens might increase the size of a struct page by a word. 24443570fd2SHeiko Carstens 2454156153cSHeiko Carstensconfig HAVE_CMPXCHG_LOCAL 2464156153cSHeiko Carstens bool 2474156153cSHeiko Carstens 2482565409fSHeiko Carstensconfig HAVE_CMPXCHG_DOUBLE 2492565409fSHeiko Carstens bool 2502565409fSHeiko Carstens 251c1d7e01dSWill Deaconconfig ARCH_WANT_IPC_PARSE_VERSION 252c1d7e01dSWill Deacon bool 253c1d7e01dSWill Deacon 254c1d7e01dSWill Deaconconfig ARCH_WANT_COMPAT_IPC_PARSE_VERSION 255c1d7e01dSWill Deacon bool 256c1d7e01dSWill Deacon 25748b25c43SChris Metcalfconfig ARCH_WANT_OLD_COMPAT_IPC 258c1d7e01dSWill Deacon select ARCH_WANT_COMPAT_IPC_PARSE_VERSION 25948b25c43SChris Metcalf bool 26048b25c43SChris Metcalf 261e2cfabdfSWill Drewryconfig HAVE_ARCH_SECCOMP_FILTER 262e2cfabdfSWill Drewry bool 263e2cfabdfSWill Drewry help 264fb0fadf9SWill Drewry An arch should select this symbol if it provides all of these things: 265bb6ea430SWill Drewry - syscall_get_arch() 266bb6ea430SWill Drewry - syscall_get_arguments() 267bb6ea430SWill Drewry - syscall_rollback() 268bb6ea430SWill Drewry - syscall_set_return_value() 269fb0fadf9SWill Drewry - SIGSYS siginfo_t support 270fb0fadf9SWill Drewry - secure_computing is called from a ptrace_event()-safe context 271fb0fadf9SWill Drewry - secure_computing return value is checked and a return value of -1 272fb0fadf9SWill Drewry results in the system call being skipped immediately. 273e2cfabdfSWill Drewry 274e2cfabdfSWill Drewryconfig SECCOMP_FILTER 275e2cfabdfSWill Drewry def_bool y 276e2cfabdfSWill Drewry depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET 277e2cfabdfSWill Drewry help 278e2cfabdfSWill Drewry Enable tasks to build secure computing environments defined 279e2cfabdfSWill Drewry in terms of Berkeley Packet Filter programs which implement 280e2cfabdfSWill Drewry task-defined system call filtering polices. 281e2cfabdfSWill Drewry 282e2cfabdfSWill Drewry See Documentation/prctl/seccomp_filter.txt for details. 283e2cfabdfSWill Drewry 284*786d35d4SDavid Howellsconfig HAVE_MOD_ARCH_SPECIFIC 285*786d35d4SDavid Howells bool 286*786d35d4SDavid Howells help 287*786d35d4SDavid Howells The arch uses struct mod_arch_specific to store data. Many arches 288*786d35d4SDavid Howells just need a simple module loader without arch specific data - those 289*786d35d4SDavid Howells should not enable this. 290*786d35d4SDavid Howells 291*786d35d4SDavid Howellsconfig MODULES_USE_ELF_RELA 292*786d35d4SDavid Howells bool 293*786d35d4SDavid Howells help 294*786d35d4SDavid Howells Modules only use ELF RELA relocations. Modules with ELF REL 295*786d35d4SDavid Howells relocations will give an error. 296*786d35d4SDavid Howells 297*786d35d4SDavid Howellsconfig MODULES_USE_ELF_REL 298*786d35d4SDavid Howells bool 299*786d35d4SDavid Howells help 300*786d35d4SDavid Howells Modules only use ELF REL relocations. Modules with ELF RELA 301*786d35d4SDavid Howells relocations will give an error. 302*786d35d4SDavid Howells 3032521f2c2SPeter Oberparleitersource "kernel/gcov/Kconfig" 304