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 7958340a07SJohannes Bergconfig HAVE_EFFICIENT_UNALIGNED_ACCESS 809ba16087SJan Beulich bool 8158340a07SJohannes Berg help 8258340a07SJohannes Berg Some architectures are unable to perform unaligned accesses 8358340a07SJohannes Berg without the use of get_unaligned/put_unaligned. Others are 8458340a07SJohannes Berg unable to perform such accesses efficiently (e.g. trap on 8558340a07SJohannes Berg unaligned access and require fixing it up in the exception 8658340a07SJohannes Berg handler.) 8758340a07SJohannes Berg 8858340a07SJohannes Berg This symbol should be selected by an architecture if it can 8958340a07SJohannes Berg perform unaligned accesses efficiently to allow different 9058340a07SJohannes Berg code paths to be selected for these cases. Some network 9158340a07SJohannes Berg drivers, for example, could opt to not fix up alignment 9258340a07SJohannes Berg problems with received packets if doing so would not help 9358340a07SJohannes Berg much. 9458340a07SJohannes Berg 9558340a07SJohannes Berg See Documentation/unaligned-memory-access.txt for more 9658340a07SJohannes Berg information on the topic of unaligned memory accesses. 9758340a07SJohannes Berg 981a94bc34SHeiko Carstensconfig HAVE_SYSCALL_WRAPPERS 991a94bc34SHeiko Carstens bool 1001a94bc34SHeiko Carstens 1019edddaa2SAnanth N Mavinakayanahalliconfig KRETPROBES 1029edddaa2SAnanth N Mavinakayanahalli def_bool y 1039edddaa2SAnanth N Mavinakayanahalli depends on KPROBES && HAVE_KRETPROBES 1049edddaa2SAnanth N Mavinakayanahalli 1057c68af6eSAvi Kivityconfig USER_RETURN_NOTIFIER 1067c68af6eSAvi Kivity bool 1077c68af6eSAvi Kivity depends on HAVE_USER_RETURN_NOTIFIER 1087c68af6eSAvi Kivity help 1097c68af6eSAvi Kivity Provide a kernel-internal notification when a cpu is about to 1107c68af6eSAvi Kivity switch to user mode. 1117c68af6eSAvi Kivity 11228b2ee20SRik van Rielconfig HAVE_IOREMAP_PROT 1139ba16087SJan Beulich bool 11428b2ee20SRik van Riel 115125e5645SMathieu Desnoyersconfig HAVE_KPROBES 1169ba16087SJan Beulich bool 1179edddaa2SAnanth N Mavinakayanahalli 1189edddaa2SAnanth N Mavinakayanahalliconfig HAVE_KRETPROBES 1199ba16087SJan Beulich bool 12074bc7ceeSArthur Kepner 121afd66255SMasami Hiramatsuconfig HAVE_OPTPROBES 122afd66255SMasami Hiramatsu bool 123d314d74cSCong Wang 124d314d74cSCong Wangconfig HAVE_NMI_WATCHDOG 125d314d74cSCong Wang bool 1261f5a4ad9SRoland McGrath# 1271f5a4ad9SRoland McGrath# An arch should select this if it provides all these things: 1281f5a4ad9SRoland McGrath# 1291f5a4ad9SRoland McGrath# task_pt_regs() in asm/processor.h or asm/ptrace.h 1301f5a4ad9SRoland McGrath# arch_has_single_step() if there is hardware single-step support 1311f5a4ad9SRoland McGrath# arch_has_block_step() if there is hardware block-step support 1321f5a4ad9SRoland McGrath# asm/syscall.h supplying asm-generic/syscall.h interface 1331f5a4ad9SRoland McGrath# linux/regset.h user_regset interfaces 1341f5a4ad9SRoland McGrath# CORE_DUMP_USE_REGSET #define'd in linux/elf.h 1351f5a4ad9SRoland McGrath# TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} 1361f5a4ad9SRoland McGrath# TIF_NOTIFY_RESUME calls tracehook_notify_resume() 1371f5a4ad9SRoland McGrath# signal delivery calls tracehook_signal_handler() 1381f5a4ad9SRoland McGrath# 1391f5a4ad9SRoland McGrathconfig HAVE_ARCH_TRACEHOOK 1409ba16087SJan Beulich bool 1411f5a4ad9SRoland McGrath 14274bc7ceeSArthur Kepnerconfig HAVE_DMA_ATTRS 1439ba16087SJan Beulich bool 1443d442233SJens Axboe 1453d442233SJens Axboeconfig USE_GENERIC_SMP_HELPERS 1469ba16087SJan Beulich bool 1479483a578SDavid Brownell 14829d5e047SThomas Gleixnerconfig GENERIC_SMP_IDLE_THREAD 14929d5e047SThomas Gleixner bool 15029d5e047SThomas Gleixner 151a6359d1eSThomas Gleixner# Select if arch init_task initializer is different to init/init_task.c 152a6359d1eSThomas Gleixnerconfig ARCH_INIT_TASK 153a4a2eb49SThomas Gleixner bool 154a4a2eb49SThomas Gleixner 155f850c30cSHeiko Carstensconfig HAVE_REGS_AND_STACK_ACCESS_API 156f850c30cSHeiko Carstens bool 157e01292b1SHeiko Carstens help 158e01292b1SHeiko Carstens This symbol should be selected by an architecure if it supports 159e01292b1SHeiko Carstens the API needed to access registers and stack entries from pt_regs, 160e01292b1SHeiko Carstens declared in asm/ptrace.h 161e01292b1SHeiko Carstens For example the kprobes-based event tracer needs this API. 162f850c30cSHeiko Carstens 1639483a578SDavid Brownellconfig HAVE_CLK 1649ba16087SJan Beulich bool 1659483a578SDavid Brownell help 1669483a578SDavid Brownell The <linux/clk.h> calls support software clock gating and 1679483a578SDavid Brownell thus are a key power management tool on many systems. 1689483a578SDavid Brownell 1695ee00bd4SJoerg Roedelconfig HAVE_DMA_API_DEBUG 1705ee00bd4SJoerg Roedel bool 17136cd3c9fSHeiko Carstens 17262a038d3SK.Prasadconfig HAVE_HW_BREAKPOINT 17362a038d3SK.Prasad bool 17499e8c5a3SFrederic Weisbecker depends on PERF_EVENTS 17562a038d3SK.Prasad 1760102752eSFrederic Weisbeckerconfig HAVE_MIXED_BREAKPOINTS_REGS 1770102752eSFrederic Weisbecker bool 1780102752eSFrederic Weisbecker depends on HAVE_HW_BREAKPOINT 1790102752eSFrederic Weisbecker help 1800102752eSFrederic Weisbecker Depending on the arch implementation of hardware breakpoints, 1810102752eSFrederic Weisbecker some of them have separate registers for data and instruction 1820102752eSFrederic Weisbecker breakpoints addresses, others have mixed registers to store 1830102752eSFrederic Weisbecker them but define the access type in a control register. 1840102752eSFrederic Weisbecker Select this option if your arch implements breakpoints under the 1850102752eSFrederic Weisbecker latter fashion. 1860102752eSFrederic Weisbecker 1877c68af6eSAvi Kivityconfig HAVE_USER_RETURN_NOTIFIER 1887c68af6eSAvi Kivity bool 189a1922ed6SIngo Molnar 190c01d4323SFrederic Weisbeckerconfig HAVE_PERF_EVENTS_NMI 191c01d4323SFrederic Weisbecker bool 19223637d47SFrederic Weisbecker help 19323637d47SFrederic Weisbecker System hardware can generate an NMI using the perf event 19423637d47SFrederic Weisbecker subsystem. Also has support for calculating CPU cycle events 19523637d47SFrederic Weisbecker to determine how many clock cycles in a given period. 196c01d4323SFrederic Weisbecker 197bf5438fcSJason Baronconfig HAVE_ARCH_JUMP_LABEL 198bf5438fcSJason Baron bool 199bf5438fcSJason Baron 200335d7afbSGerald Schaeferconfig HAVE_ARCH_MUTEX_CPU_RELAX 201335d7afbSGerald Schaefer bool 202335d7afbSGerald Schaefer 20326723911SPeter Zijlstraconfig HAVE_RCU_TABLE_FREE 20426723911SPeter Zijlstra bool 20526723911SPeter Zijlstra 206df013ffbSHuang Yingconfig ARCH_HAVE_NMI_SAFE_CMPXCHG 207df013ffbSHuang Ying bool 208df013ffbSHuang Ying 20943570fd2SHeiko Carstensconfig HAVE_ALIGNED_STRUCT_PAGE 21043570fd2SHeiko Carstens bool 21143570fd2SHeiko Carstens help 21243570fd2SHeiko Carstens This makes sure that struct pages are double word aligned and that 21343570fd2SHeiko Carstens e.g. the SLUB allocator can perform double word atomic operations 21443570fd2SHeiko Carstens on a struct page for better performance. However selecting this 21543570fd2SHeiko Carstens might increase the size of a struct page by a word. 21643570fd2SHeiko Carstens 2174156153cSHeiko Carstensconfig HAVE_CMPXCHG_LOCAL 2184156153cSHeiko Carstens bool 2194156153cSHeiko Carstens 2202565409fSHeiko Carstensconfig HAVE_CMPXCHG_DOUBLE 2212565409fSHeiko Carstens bool 2222565409fSHeiko Carstens 22348b25c43SChris Metcalfconfig ARCH_WANT_OLD_COMPAT_IPC 22448b25c43SChris Metcalf bool 22548b25c43SChris Metcalf 2262521f2c2SPeter Oberparleitersource "kernel/gcov/Kconfig" 227