arch/Kconfig

   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         select RING_BUFFER
  10         select RING_BUFFER_ALLOW_SWAP
  11         help
  12           OProfile is a profiling system capable of profiling the
  13           whole system, include the kernel, kernel modules, libraries,
  14           and applications.
  15
  16           If unsure, say N.
  17
  18 config OPROFILE_EVENT_MULTIPLEX
  19         bool "OProfile multiplexing support (EXPERIMENTAL)"
  20         default n
  21         depends on OPROFILE && X86
  22         help
  23           The number of hardware counters is limited. The multiplexing
  24           feature enables OProfile to gather more events than counters
  25           are provided by the hardware. This is realized by switching
  26           between events at an user specified time interval.
  27
  28           If unsure, say N.
  29
  30 config HAVE_OPROFILE
  31         bool
  32
  33 config OPROFILE_NMI_TIMER
  34         def_bool y
  35         depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
  36
  37 config KPROBES
  38         bool "Kprobes"
  39         depends on MODULES
  40         depends on HAVE_KPROBES
  41         select KALLSYMS
  42         help
  43           Kprobes allows you to trap at almost any kernel address and
  44           execute a callback function.  register_kprobe() establishes
  45           a probepoint and specifies the callback.  Kprobes is useful
  46           for kernel debugging, non-intrusive instrumentation and testing.
  47           If in doubt, say "N".
  48
  49 config JUMP_LABEL
  50        bool "Optimize very unlikely/likely branches"
  51        depends on HAVE_ARCH_JUMP_LABEL
  52        help
  53          This option enables a transparent branch optimization that
  54          makes certain almost-always-true or almost-always-false branch
  55          conditions even cheaper to execute within the kernel.
  56
  57          Certain performance-sensitive kernel code, such as trace points,
  58          scheduler functionality, networking code and KVM have such
  59          branches and include support for this optimization technique.
  60
  61          If it is detected that the compiler has support for "asm goto",
  62          the kernel will compile such branches with just a nop
  63          instruction. When the condition flag is toggled to true, the
  64          nop will be converted to a jump instruction to execute the
  65          conditional block of instructions.
  66
  67          This technique lowers overhead and stress on the branch prediction
  68          of the processor and generally makes the kernel faster. The update
  69          of the condition is slower, but those are always very rare.
  70
  71          ( On 32-bit x86, the necessary options added to the compiler
  72            flags may increase the size of the kernel slightly. )
  73
  74 config OPTPROBES
  75         def_bool y
  76         depends on KPROBES && HAVE_OPTPROBES
  77         depends on !PREEMPT
  78
  79 config UPROBES
  80         bool "Transparent user-space probes (EXPERIMENTAL)"
  81         depends on UPROBE_EVENT && PERF_EVENTS
  82         default n
  83         help
  84           Uprobes is the user-space counterpart to kprobes: they
  85           enable instrumentation applications (such as 'perf probe')
  86           to establish unintrusive probes in user-space binaries and
  87           libraries, by executing handler functions when the probes
  88           are hit by user-space applications.
  89
  90           ( These probes come in the form of single-byte breakpoints,
  91             managed by the kernel and kept transparent to the probed
  92             application. )
  93
  94           If in doubt, say "N".
  95
  96 config HAVE_EFFICIENT_UNALIGNED_ACCESS
  97         bool
  98         help
  99           Some architectures are unable to perform unaligned accesses
 100           without the use of get_unaligned/put_unaligned. Others are
 101           unable to perform such accesses efficiently (e.g. trap on
 102           unaligned access and require fixing it up in the exception
 103           handler.)
 104
 105           This symbol should be selected by an architecture if it can
 106           perform unaligned accesses efficiently to allow different
 107           code paths to be selected for these cases. Some network
 108           drivers, for example, could opt to not fix up alignment
 109           problems with received packets if doing so would not help
 110           much.
 111
 112           See Documentation/unaligned-memory-access.txt for more
 113           information on the topic of unaligned memory accesses.
 114
 115 config HAVE_SYSCALL_WRAPPERS
 116         bool
 117
 118 config KRETPROBES
 119         def_bool y
 120         depends on KPROBES && HAVE_KRETPROBES
 121
 122 config USER_RETURN_NOTIFIER
 123         bool
 124         depends on HAVE_USER_RETURN_NOTIFIER
 125         help
 126           Provide a kernel-internal notification when a cpu is about to
 127           switch to user mode.
 128
 129 config HAVE_IOREMAP_PROT
 130         bool
 131
 132 config HAVE_KPROBES
 133         bool
 134
 135 config HAVE_KRETPROBES
 136         bool
 137
 138 config HAVE_OPTPROBES
 139         bool
 140
 141 config HAVE_NMI_WATCHDOG
 142         bool
 143 #
 144 # An arch should select this if it provides all these things:
 145 #
 146 #       task_pt_regs()          in asm/processor.h or asm/ptrace.h
 147 #       arch_has_single_step()  if there is hardware single-step support
 148 #       arch_has_block_step()   if there is hardware block-step support
 149 #       asm/syscall.h           supplying asm-generic/syscall.h interface
 150 #       linux/regset.h          user_regset interfaces
 151 #       CORE_DUMP_USE_REGSET    #define'd in linux/elf.h
 152 #       TIF_SYSCALL_TRACE       calls tracehook_report_syscall_{entry,exit}
 153 #       TIF_NOTIFY_RESUME       calls tracehook_notify_resume()
 154 #       signal delivery         calls tracehook_signal_handler()
 155 #
 156 config HAVE_ARCH_TRACEHOOK
 157         bool
 158
 159 config HAVE_DMA_ATTRS
 160         bool
 161
 162 config USE_GENERIC_SMP_HELPERS
 163         bool
 164
 165 config GENERIC_SMP_IDLE_THREAD
 166        bool
 167
 168 # Select if arch init_task initializer is different to init/init_task.c
 169 config ARCH_INIT_TASK
 170        bool
 171
 172 # Select if arch has its private alloc_task_struct() function
 173 config ARCH_TASK_STRUCT_ALLOCATOR
 174         bool
 175
 176 # Select if arch has its private alloc_thread_info() function
 177 config ARCH_THREAD_INFO_ALLOCATOR
 178         bool
 179
 180 config HAVE_REGS_AND_STACK_ACCESS_API
 181         bool
 182         help
 183           This symbol should be selected by an architecure if it supports
 184           the API needed to access registers and stack entries from pt_regs,
 185           declared in asm/ptrace.h
 186           For example the kprobes-based event tracer needs this API.
 187
 188 config HAVE_CLK
 189         bool
 190         help
 191           The <linux/clk.h> calls support software clock gating and
 192           thus are a key power management tool on many systems.
 193
 194 config HAVE_DMA_API_DEBUG
 195         bool
 196
 197 config HAVE_HW_BREAKPOINT
 198         bool
 199         depends on PERF_EVENTS
 200
 201 config HAVE_MIXED_BREAKPOINTS_REGS
 202         bool
 203         depends on HAVE_HW_BREAKPOINT
 204         help
 205           Depending on the arch implementation of hardware breakpoints,
 206           some of them have separate registers for data and instruction
 207           breakpoints addresses, others have mixed registers to store
 208           them but define the access type in a control register.
 209           Select this option if your arch implements breakpoints under the
 210           latter fashion.
 211
 212 config HAVE_USER_RETURN_NOTIFIER
 213         bool
 214
 215 config HAVE_PERF_EVENTS_NMI
 216         bool
 217         help
 218           System hardware can generate an NMI using the perf event
 219           subsystem.  Also has support for calculating CPU cycle events
 220           to determine how many clock cycles in a given period.
 221
 222 config HAVE_ARCH_JUMP_LABEL
 223         bool
 224
 225 config HAVE_ARCH_MUTEX_CPU_RELAX
 226         bool
 227
 228 config HAVE_RCU_TABLE_FREE
 229         bool
 230
 231 config ARCH_HAVE_NMI_SAFE_CMPXCHG
 232         bool
 233
 234 config HAVE_ALIGNED_STRUCT_PAGE
 235         bool
 236         help
 237           This makes sure that struct pages are double word aligned and that
 238           e.g. the SLUB allocator can perform double word atomic operations
 239           on a struct page for better performance. However selecting this
 240           might increase the size of a struct page by a word.
 241
 242 config HAVE_CMPXCHG_LOCAL
 243         bool
 244
 245 config HAVE_CMPXCHG_DOUBLE
 246         bool
 247
 248 config ARCH_WANT_OLD_COMPAT_IPC
 249         bool
 250
 251 config HAVE_ARCH_SECCOMP_FILTER
 252         bool
 253         help
 254           An arch should select this symbol if it provides all of these things:
 255           - syscall_get_arch()
 256           - syscall_get_arguments()
 257           - syscall_rollback()
 258           - syscall_set_return_value()
 259           - SIGSYS siginfo_t support
 260           - secure_computing is called from a ptrace_event()-safe context
 261           - secure_computing return value is checked and a return value of -1
 262             results in the system call being skipped immediately.
 263
 264 config SECCOMP_FILTER
 265         def_bool y
 266         depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
 267         help
 268           Enable tasks to build secure computing environments defined
 269           in terms of Berkeley Packet Filter programs which implement
 270           task-defined system call filtering polices.
 271
 272           See Documentation/prctl/seccomp_filter.txt for details.
 273
 274 source "kernel/gcov/Kconfig"