lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | # |
| 2 | # General architecture dependent options |
| 3 | # |
| 4 | |
| 5 | config OPROFILE |
| 6 | tristate "OProfile system profiling" |
| 7 | depends on PROFILING |
| 8 | depends on HAVE_OPROFILE |
| 9 | depends on !PREEMPT_RT_FULL |
| 10 | select RING_BUFFER |
| 11 | select RING_BUFFER_ALLOW_SWAP |
| 12 | help |
| 13 | OProfile is a profiling system capable of profiling the |
| 14 | whole system, include the kernel, kernel modules, libraries, |
| 15 | and applications. |
| 16 | |
| 17 | If unsure, say N. |
| 18 | |
| 19 | config OPROFILE_EVENT_MULTIPLEX |
| 20 | bool "OProfile multiplexing support (EXPERIMENTAL)" |
| 21 | default n |
| 22 | depends on OPROFILE && X86 |
| 23 | help |
| 24 | The number of hardware counters is limited. The multiplexing |
| 25 | feature enables OProfile to gather more events than counters |
| 26 | are provided by the hardware. This is realized by switching |
| 27 | between events at an user specified time interval. |
| 28 | |
| 29 | If unsure, say N. |
| 30 | |
| 31 | config HAVE_OPROFILE |
| 32 | bool |
| 33 | |
| 34 | config OPROFILE_NMI_TIMER |
| 35 | def_bool y |
| 36 | depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI |
| 37 | |
| 38 | config KPROBES |
| 39 | bool "Kprobes" |
| 40 | depends on MODULES |
| 41 | depends on HAVE_KPROBES |
| 42 | select KALLSYMS |
| 43 | help |
| 44 | Kprobes allows you to trap at almost any kernel address and |
| 45 | execute a callback function. register_kprobe() establishes |
| 46 | a probepoint and specifies the callback. Kprobes is useful |
| 47 | for kernel debugging, non-intrusive instrumentation and testing. |
| 48 | If in doubt, say "N". |
| 49 | |
| 50 | config JUMP_LABEL |
| 51 | bool "Optimize very unlikely/likely branches" |
| 52 | depends on HAVE_ARCH_JUMP_LABEL |
| 53 | depends on (!INTERRUPT_OFF_HIST && !PREEMPT_OFF_HIST && !WAKEUP_LATENCY_HIST && !MISSED_TIMER_OFFSETS_HIST) |
| 54 | help |
| 55 | This option enables a transparent branch optimization that |
| 56 | makes certain almost-always-true or almost-always-false branch |
| 57 | conditions even cheaper to execute within the kernel. |
| 58 | |
| 59 | Certain performance-sensitive kernel code, such as trace points, |
| 60 | scheduler functionality, networking code and KVM have such |
| 61 | branches and include support for this optimization technique. |
| 62 | |
| 63 | If it is detected that the compiler has support for "asm goto", |
| 64 | the kernel will compile such branches with just a nop |
| 65 | instruction. When the condition flag is toggled to true, the |
| 66 | nop will be converted to a jump instruction to execute the |
| 67 | conditional block of instructions. |
| 68 | |
| 69 | This technique lowers overhead and stress on the branch prediction |
| 70 | of the processor and generally makes the kernel faster. The update |
| 71 | of the condition is slower, but those are always very rare. |
| 72 | |
| 73 | ( On 32-bit x86, the necessary options added to the compiler |
| 74 | flags may increase the size of the kernel slightly. ) |
| 75 | |
| 76 | config OPTPROBES |
| 77 | def_bool y |
| 78 | depends on KPROBES && HAVE_OPTPROBES |
| 79 | depends on !PREEMPT |
| 80 | |
| 81 | config HAVE_EFFICIENT_UNALIGNED_ACCESS |
| 82 | bool |
| 83 | help |
| 84 | Some architectures are unable to perform unaligned accesses |
| 85 | without the use of get_unaligned/put_unaligned. Others are |
| 86 | unable to perform such accesses efficiently (e.g. trap on |
| 87 | unaligned access and require fixing it up in the exception |
| 88 | handler.) |
| 89 | |
| 90 | This symbol should be selected by an architecture if it can |
| 91 | perform unaligned accesses efficiently to allow different |
| 92 | code paths to be selected for these cases. Some network |
| 93 | drivers, for example, could opt to not fix up alignment |
| 94 | problems with received packets if doing so would not help |
| 95 | much. |
| 96 | |
| 97 | See Documentation/unaligned-memory-access.txt for more |
| 98 | information on the topic of unaligned memory accesses. |
| 99 | |
| 100 | config HAVE_SYSCALL_WRAPPERS |
| 101 | bool |
| 102 | |
| 103 | config KRETPROBES |
| 104 | def_bool y |
| 105 | depends on KPROBES && HAVE_KRETPROBES |
| 106 | |
| 107 | config USER_RETURN_NOTIFIER |
| 108 | bool |
| 109 | depends on HAVE_USER_RETURN_NOTIFIER |
| 110 | help |
| 111 | Provide a kernel-internal notification when a cpu is about to |
| 112 | switch to user mode. |
| 113 | |
| 114 | config HAVE_IOREMAP_PROT |
| 115 | bool |
| 116 | |
| 117 | config HAVE_KPROBES |
| 118 | bool |
| 119 | |
| 120 | config HAVE_KRETPROBES |
| 121 | bool |
| 122 | |
| 123 | config HAVE_OPTPROBES |
| 124 | bool |
| 125 | |
| 126 | config HAVE_NMI_WATCHDOG |
| 127 | bool |
| 128 | # |
| 129 | # An arch should select this if it provides all these things: |
| 130 | # |
| 131 | # task_pt_regs() in asm/processor.h or asm/ptrace.h |
| 132 | # arch_has_single_step() if there is hardware single-step support |
| 133 | # arch_has_block_step() if there is hardware block-step support |
| 134 | # asm/syscall.h supplying asm-generic/syscall.h interface |
| 135 | # linux/regset.h user_regset interfaces |
| 136 | # CORE_DUMP_USE_REGSET #define'd in linux/elf.h |
| 137 | # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} |
| 138 | # TIF_NOTIFY_RESUME calls tracehook_notify_resume() |
| 139 | # signal delivery calls tracehook_signal_handler() |
| 140 | # |
| 141 | config HAVE_ARCH_TRACEHOOK |
| 142 | bool |
| 143 | |
| 144 | config HAVE_DMA_ATTRS |
| 145 | bool |
| 146 | |
| 147 | config USE_GENERIC_SMP_HELPERS |
| 148 | bool |
| 149 | |
| 150 | config HAVE_REGS_AND_STACK_ACCESS_API |
| 151 | bool |
| 152 | help |
| 153 | This symbol should be selected by an architecure if it supports |
| 154 | the API needed to access registers and stack entries from pt_regs, |
| 155 | declared in asm/ptrace.h |
| 156 | For example the kprobes-based event tracer needs this API. |
| 157 | |
| 158 | config HAVE_CLK |
| 159 | bool |
| 160 | help |
| 161 | The <linux/clk.h> calls support software clock gating and |
| 162 | thus are a key power management tool on many systems. |
| 163 | |
| 164 | config HAVE_DMA_API_DEBUG |
| 165 | bool |
| 166 | |
| 167 | config HAVE_HW_BREAKPOINT |
| 168 | bool |
| 169 | depends on PERF_EVENTS |
| 170 | |
| 171 | config HAVE_MIXED_BREAKPOINTS_REGS |
| 172 | bool |
| 173 | depends on HAVE_HW_BREAKPOINT |
| 174 | help |
| 175 | Depending on the arch implementation of hardware breakpoints, |
| 176 | some of them have separate registers for data and instruction |
| 177 | breakpoints addresses, others have mixed registers to store |
| 178 | them but define the access type in a control register. |
| 179 | Select this option if your arch implements breakpoints under the |
| 180 | latter fashion. |
| 181 | |
| 182 | config HAVE_USER_RETURN_NOTIFIER |
| 183 | bool |
| 184 | |
| 185 | config HAVE_PERF_EVENTS_NMI |
| 186 | bool |
| 187 | help |
| 188 | System hardware can generate an NMI using the perf event |
| 189 | subsystem. Also has support for calculating CPU cycle events |
| 190 | to determine how many clock cycles in a given period. |
| 191 | |
| 192 | config HAVE_ARCH_JUMP_LABEL |
| 193 | bool |
| 194 | |
| 195 | config HAVE_ARCH_MUTEX_CPU_RELAX |
| 196 | bool |
| 197 | |
| 198 | config HAVE_RCU_TABLE_FREE |
| 199 | bool |
| 200 | |
| 201 | config ARCH_HAVE_NMI_SAFE_CMPXCHG |
| 202 | bool |
| 203 | |
| 204 | config HAVE_ALIGNED_STRUCT_PAGE |
| 205 | bool |
| 206 | help |
| 207 | This makes sure that struct pages are double word aligned and that |
| 208 | e.g. the SLUB allocator can perform double word atomic operations |
| 209 | on a struct page for better performance. However selecting this |
| 210 | might increase the size of a struct page by a word. |
| 211 | |
| 212 | config HAVE_CMPXCHG_LOCAL |
| 213 | bool |
| 214 | |
| 215 | config HAVE_CMPXCHG_DOUBLE |
| 216 | bool |
| 217 | |
| 218 | config ARCH_WANT_OLD_COMPAT_IPC |
| 219 | bool |
| 220 | |
| 221 | source "kernel/gcov/Kconfig" |