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 HAVE_EFFICIENT_UNALIGNED_ACCESS
  80         bool
  81         help
  82           Some architectures are unable to perform unaligned accesses
  83           without the use of get_unaligned/put_unaligned. Others are
  84           unable to perform such accesses efficiently (e.g. trap on
  85           unaligned access and require fixing it up in the exception
  86           handler.)
  87
  88           This symbol should be selected by an architecture if it can
  89           perform unaligned accesses efficiently to allow different
  90           code paths to be selected for these cases. Some network
  91           drivers, for example, could opt to not fix up alignment
  92           problems with received packets if doing so would not help
  93           much.
  94
  95           See Documentation/unaligned-memory-access.txt for more
  96           information on the topic of unaligned memory accesses.
  97
  98 config HAVE_SYSCALL_WRAPPERS
  99         bool
 100
 101 config KRETPROBES
 102         def_bool y
 103         depends on KPROBES && HAVE_KRETPROBES
 104
 105 config USER_RETURN_NOTIFIER
 106         bool
 107         depends on HAVE_USER_RETURN_NOTIFIER
 108         help
 109           Provide a kernel-internal notification when a cpu is about to
 110           switch to user mode.
 111
 112 config HAVE_IOREMAP_PROT
 113         bool
 114
 115 config HAVE_KPROBES
 116         bool
 117
 118 config HAVE_KRETPROBES
 119         bool
 120
 121 config HAVE_OPTPROBES
 122         bool
 123
 124 config HAVE_NMI_WATCHDOG
 125         bool
 126 #
 127 # An arch should select this if it provides all these things:
 128 #
 129 #       task_pt_regs()          in asm/processor.h or asm/ptrace.h
 130 #       arch_has_single_step()  if there is hardware single-step support
 131 #       arch_has_block_step()   if there is hardware block-step support
 132 #       asm/syscall.h           supplying asm-generic/syscall.h interface
 133 #       linux/regset.h          user_regset interfaces
 134 #       CORE_DUMP_USE_REGSET    #define'd in linux/elf.h
 135 #       TIF_SYSCALL_TRACE       calls tracehook_report_syscall_{entry,exit}
 136 #       TIF_NOTIFY_RESUME       calls tracehook_notify_resume()
 137 #       signal delivery         calls tracehook_signal_handler()
 138 #
 139 config HAVE_ARCH_TRACEHOOK
 140         bool
 141
 142 config HAVE_DMA_ATTRS
 143         bool
 144
 145 config USE_GENERIC_SMP_HELPERS
 146         bool
 147
 148 config GENERIC_SMP_IDLE_THREAD
 149        bool
 150
 151 # Select if arch init_task initializer is different to init/init_task.c
 152 config ARCH_INIT_TASK
 153        bool
 154
 155 # Select if arch has its private alloc_task_struct() function
 156 config ARCH_TASK_STRUCT_ALLOCATOR
 157         bool
 158
 159 # Select if arch has its private alloc_thread_info() function
 160 config ARCH_THREAD_INFO_ALLOCATOR
 161         bool
 162
 163 config HAVE_REGS_AND_STACK_ACCESS_API
 164         bool
 165         help
 166           This symbol should be selected by an architecure if it supports
 167           the API needed to access registers and stack entries from pt_regs,
 168           declared in asm/ptrace.h
 169           For example the kprobes-based event tracer needs this API.
 170
 171 config HAVE_CLK
 172         bool
 173         help
 174           The <linux/clk.h> calls support software clock gating and
 175           thus are a key power management tool on many systems.
 176
 177 config HAVE_DMA_API_DEBUG
 178         bool
 179
 180 config HAVE_HW_BREAKPOINT
 181         bool
 182         depends on PERF_EVENTS
 183
 184 config HAVE_MIXED_BREAKPOINTS_REGS
 185         bool
 186         depends on HAVE_HW_BREAKPOINT
 187         help
 188           Depending on the arch implementation of hardware breakpoints,
 189           some of them have separate registers for data and instruction
 190           breakpoints addresses, others have mixed registers to store
 191           them but define the access type in a control register.
 192           Select this option if your arch implements breakpoints under the
 193           latter fashion.
 194
 195 config HAVE_USER_RETURN_NOTIFIER
 196         bool
 197
 198 config HAVE_PERF_EVENTS_NMI
 199         bool
 200         help
 201           System hardware can generate an NMI using the perf event
 202           subsystem.  Also has support for calculating CPU cycle events
 203           to determine how many clock cycles in a given period.
 204
 205 config HAVE_ARCH_JUMP_LABEL
 206         bool
 207
 208 config HAVE_ARCH_MUTEX_CPU_RELAX
 209         bool
 210
 211 config HAVE_RCU_TABLE_FREE
 212         bool
 213
 214 config ARCH_HAVE_NMI_SAFE_CMPXCHG
 215         bool
 216
 217 config HAVE_ALIGNED_STRUCT_PAGE
 218         bool
 219         help
 220           This makes sure that struct pages are double word aligned and that
 221           e.g. the SLUB allocator can perform double word atomic operations
 222           on a struct page for better performance. However selecting this
 223           might increase the size of a struct page by a word.
 224
 225 config HAVE_CMPXCHG_LOCAL
 226         bool
 227
 228 config HAVE_CMPXCHG_DOUBLE
 229         bool
 230
 231 config ARCH_WANT_OLD_COMPAT_IPC
 232         bool
 233
 234 config HAVE_ARCH_SECCOMP_FILTER
 235         bool
 236         help
 237           An arch should select this symbol if it provides all of these things:
 238           - syscall_get_arch()
 239           - syscall_get_arguments()
 240           - syscall_rollback()
 241           - syscall_set_return_value()
 242           - SIGSYS siginfo_t support
 243           - secure_computing is called from a ptrace_event()-safe context
 244           - secure_computing return value is checked and a return value of -1
 245             results in the system call being skipped immediately.
 246
 247 config SECCOMP_FILTER
 248         def_bool y
 249         depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
 250         help
 251           Enable tasks to build secure computing environments defined
 252           in terms of Berkeley Packet Filter programs which implement
 253           task-defined system call filtering polices.
 254
 255           See Documentation/prctl/seccomp_filter.txt for details.
 256
 257 source "kernel/gcov/Kconfig"