| # |
| # General architecture dependent options |
| # |
| |
| config OPROFILE |
| tristate "OProfile system profiling" |
| depends on PROFILING |
| depends on HAVE_OPROFILE |
| select RING_BUFFER |
| select RING_BUFFER_ALLOW_SWAP |
| help |
| OProfile is a profiling system capable of profiling the |
| whole system, include the kernel, kernel modules, libraries, |
| and applications. |
| |
| If unsure, say N. |
| |
| config OPROFILE_EVENT_MULTIPLEX |
| bool "OProfile multiplexing support (EXPERIMENTAL)" |
| default n |
| depends on OPROFILE && X86 |
| help |
| The number of hardware counters is limited. The multiplexing |
| feature enables OProfile to gather more events than counters |
| are provided by the hardware. This is realized by switching |
| between events at an user specified time interval. |
| |
| If unsure, say N. |
| |
| config HAVE_OPROFILE |
| bool |
| |
| config OPROFILE_NMI_TIMER |
| def_bool y |
| depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI |
| |
| config KPROBES |
| bool "Kprobes" |
| depends on MODULES |
| depends on HAVE_KPROBES |
| select KALLSYMS |
| help |
| Kprobes allows you to trap at almost any kernel address and |
| execute a callback function. register_kprobe() establishes |
| a probepoint and specifies the callback. Kprobes is useful |
| for kernel debugging, non-intrusive instrumentation and testing. |
| If in doubt, say "N". |
| |
| config JUMP_LABEL |
| bool "Optimize very unlikely/likely branches" |
| depends on HAVE_ARCH_JUMP_LABEL |
| help |
| This option enables a transparent branch optimization that |
| makes certain almost-always-true or almost-always-false branch |
| conditions even cheaper to execute within the kernel. |
| |
| Certain performance-sensitive kernel code, such as trace points, |
| scheduler functionality, networking code and KVM have such |
| branches and include support for this optimization technique. |
| |
| If it is detected that the compiler has support for "asm goto", |
| the kernel will compile such branches with just a nop |
| instruction. When the condition flag is toggled to true, the |
| nop will be converted to a jump instruction to execute the |
| conditional block of instructions. |
| |
| This technique lowers overhead and stress on the branch prediction |
| of the processor and generally makes the kernel faster. The update |
| of the condition is slower, but those are always very rare. |
| |
| ( On 32-bit x86, the necessary options added to the compiler |
| flags may increase the size of the kernel slightly. ) |
| |
| config OPTPROBES |
| def_bool y |
| depends on KPROBES && HAVE_OPTPROBES |
| depends on !PREEMPT |
| |
| config UPROBES |
| bool "Transparent user-space probes (EXPERIMENTAL)" |
| depends on UPROBE_EVENT && PERF_EVENTS |
| default n |
| select PERCPU_RWSEM |
| help |
| Uprobes is the user-space counterpart to kprobes: they |
| enable instrumentation applications (such as 'perf probe') |
| to establish unintrusive probes in user-space binaries and |
| libraries, by executing handler functions when the probes |
| are hit by user-space applications. |
| |
| ( These probes come in the form of single-byte breakpoints, |
| managed by the kernel and kept transparent to the probed |
| application. ) |
| |
| If in doubt, say "N". |
| |
| config HAVE_EFFICIENT_UNALIGNED_ACCESS |
| bool |
| help |
| Some architectures are unable to perform unaligned accesses |
| without the use of get_unaligned/put_unaligned. Others are |
| unable to perform such accesses efficiently (e.g. trap on |
| unaligned access and require fixing it up in the exception |
| handler.) |
| |
| This symbol should be selected by an architecture if it can |
| perform unaligned accesses efficiently to allow different |
| code paths to be selected for these cases. Some network |
| drivers, for example, could opt to not fix up alignment |
| problems with received packets if doing so would not help |
| much. |
| |
| See Documentation/unaligned-memory-access.txt for more |
| information on the topic of unaligned memory accesses. |
| |
| config ARCH_USE_BUILTIN_BSWAP |
| bool |
| help |
| Modern versions of GCC (since 4.4) have builtin functions |
| for handling byte-swapping. Using these, instead of the old |
| inline assembler that the architecture code provides in the |
| __arch_bswapXX() macros, allows the compiler to see what's |
| happening and offers more opportunity for optimisation. In |
| particular, the compiler will be able to combine the byteswap |
| with a nearby load or store and use load-and-swap or |
| store-and-swap instructions if the architecture has them. It |
| should almost *never* result in code which is worse than the |
| hand-coded assembler in <asm/swab.h>. But just in case it |
| does, the use of the builtins is optional. |
| |
| Any architecture with load-and-swap or store-and-swap |
| instructions should set this. And it shouldn't hurt to set it |
| on architectures that don't have such instructions. |
| |
| config HAVE_SYSCALL_WRAPPERS |
| bool |
| |
| config KRETPROBES |
| def_bool y |
| depends on KPROBES && HAVE_KRETPROBES |
| |
| config USER_RETURN_NOTIFIER |
| bool |
| depends on HAVE_USER_RETURN_NOTIFIER |
| help |
| Provide a kernel-internal notification when a cpu is about to |
| switch to user mode. |
| |
| config HAVE_IOREMAP_PROT |
| bool |
| |
| config HAVE_KPROBES |
| bool |
| |
| config HAVE_KRETPROBES |
| bool |
| |
| config HAVE_OPTPROBES |
| bool |
| |
| config HAVE_NMI_WATCHDOG |
| bool |
| # |
| # An arch should select this if it provides all these things: |
| # |
| # task_pt_regs() in asm/processor.h or asm/ptrace.h |
| # arch_has_single_step() if there is hardware single-step support |
| # arch_has_block_step() if there is hardware block-step support |
| # asm/syscall.h supplying asm-generic/syscall.h interface |
| # linux/regset.h user_regset interfaces |
| # CORE_DUMP_USE_REGSET #define'd in linux/elf.h |
| # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} |
| # TIF_NOTIFY_RESUME calls tracehook_notify_resume() |
| # signal delivery calls tracehook_signal_handler() |
| # |
| config HAVE_ARCH_TRACEHOOK |
| bool |
| |
| config HAVE_DMA_ATTRS |
| bool |
| |
| config HAVE_DMA_CONTIGUOUS |
| bool |
| |
| config USE_GENERIC_SMP_HELPERS |
| bool |
| |
| config GENERIC_SMP_IDLE_THREAD |
| bool |
| |
| # Select if arch init_task initializer is different to init/init_task.c |
| config ARCH_INIT_TASK |
| bool |
| |
| # Select if arch has its private alloc_task_struct() function |
| config ARCH_TASK_STRUCT_ALLOCATOR |
| bool |
| |
| # Select if arch has its private alloc_thread_info() function |
| config ARCH_THREAD_INFO_ALLOCATOR |
| bool |
| |
| config HAVE_REGS_AND_STACK_ACCESS_API |
| bool |
| help |
| This symbol should be selected by an architecure if it supports |
| the API needed to access registers and stack entries from pt_regs, |
| declared in asm/ptrace.h |
| For example the kprobes-based event tracer needs this API. |
| |
| config HAVE_CLK |
| bool |
| help |
| The <linux/clk.h> calls support software clock gating and |
| thus are a key power management tool on many systems. |
| |
| config HAVE_DMA_API_DEBUG |
| bool |
| |
| config HAVE_HW_BREAKPOINT |
| bool |
| depends on PERF_EVENTS |
| |
| config HAVE_MIXED_BREAKPOINTS_REGS |
| bool |
| depends on HAVE_HW_BREAKPOINT |
| help |
| Depending on the arch implementation of hardware breakpoints, |
| some of them have separate registers for data and instruction |
| breakpoints addresses, others have mixed registers to store |
| them but define the access type in a control register. |
| Select this option if your arch implements breakpoints under the |
| latter fashion. |
| |
| config HAVE_USER_RETURN_NOTIFIER |
| bool |
| |
| config HAVE_PERF_EVENTS_NMI |
| bool |
| help |
| System hardware can generate an NMI using the perf event |
| subsystem. Also has support for calculating CPU cycle events |
| to determine how many clock cycles in a given period. |
| |
| config HAVE_PERF_REGS |
| bool |
| help |
| Support selective register dumps for perf events. This includes |
| bit-mapping of each registers and a unique architecture id. |
| |
| config HAVE_PERF_USER_STACK_DUMP |
| bool |
| help |
| Support user stack dumps for perf event samples. This needs |
| access to the user stack pointer which is not unified across |
| architectures. |
| |
| config HAVE_ARCH_JUMP_LABEL |
| bool |
| |
| config HAVE_ARCH_MUTEX_CPU_RELAX |
| bool |
| |
| config HAVE_RCU_TABLE_FREE |
| bool |
| |
| config ARCH_HAVE_NMI_SAFE_CMPXCHG |
| bool |
| |
| config HAVE_ALIGNED_STRUCT_PAGE |
| bool |
| help |
| This makes sure that struct pages are double word aligned and that |
| e.g. the SLUB allocator can perform double word atomic operations |
| on a struct page for better performance. However selecting this |
| might increase the size of a struct page by a word. |
| |
| config HAVE_CMPXCHG_LOCAL |
| bool |
| |
| config HAVE_CMPXCHG_DOUBLE |
| bool |
| |
| config ARCH_WANT_IPC_PARSE_VERSION |
| bool |
| |
| config ARCH_WANT_COMPAT_IPC_PARSE_VERSION |
| bool |
| |
| config ARCH_WANT_OLD_COMPAT_IPC |
| select ARCH_WANT_COMPAT_IPC_PARSE_VERSION |
| bool |
| |
| config HAVE_ARCH_SECCOMP_FILTER |
| bool |
| help |
| An arch should select this symbol if it provides all of these things: |
| - syscall_get_arch() |
| - syscall_get_arguments() |
| - syscall_rollback() |
| - syscall_set_return_value() |
| - SIGSYS siginfo_t support |
| - secure_computing is called from a ptrace_event()-safe context |
| - secure_computing return value is checked and a return value of -1 |
| results in the system call being skipped immediately. |
| |
| config SECCOMP_FILTER |
| def_bool y |
| depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET |
| help |
| Enable tasks to build secure computing environments defined |
| in terms of Berkeley Packet Filter programs which implement |
| task-defined system call filtering polices. |
| |
| See Documentation/prctl/seccomp_filter.txt for details. |
| |
| config HAVE_CONTEXT_TRACKING |
| bool |
| help |
| Provide kernel/user boundaries probes necessary for subsystems |
| that need it, such as userspace RCU extended quiescent state. |
| Syscalls need to be wrapped inside user_exit()-user_enter() through |
| the slow path using TIF_NOHZ flag. Exceptions handlers must be |
| wrapped as well. Irqs are already protected inside |
| rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on |
| irq exit still need to be protected. |
| |
| config HAVE_VIRT_CPU_ACCOUNTING |
| bool |
| |
| config HAVE_IRQ_TIME_ACCOUNTING |
| bool |
| help |
| Archs need to ensure they use a high enough resolution clock to |
| support irq time accounting and then call enable_sched_clock_irqtime(). |
| |
| config HAVE_ARCH_TRANSPARENT_HUGEPAGE |
| bool |
| |
| config HAVE_MOD_ARCH_SPECIFIC |
| bool |
| help |
| The arch uses struct mod_arch_specific to store data. Many arches |
| just need a simple module loader without arch specific data - those |
| should not enable this. |
| |
| config MODULES_USE_ELF_RELA |
| bool |
| help |
| Modules only use ELF RELA relocations. Modules with ELF REL |
| relocations will give an error. |
| |
| config MODULES_USE_ELF_REL |
| bool |
| help |
| Modules only use ELF REL relocations. Modules with ELF RELA |
| relocations will give an error. |
| |
| config GENERIC_SIGALTSTACK |
| bool |
| |
| # |
| # ABI hall of shame |
| # |
| config CLONE_BACKWARDS |
| bool |
| help |
| Architecture has tls passed as the 4th argument of clone(2), |
| not the 5th one. |
| |
| config CLONE_BACKWARDS2 |
| bool |
| help |
| Architecture has the first two arguments of clone(2) swapped. |
| |
| source "kernel/gcov/Kconfig" |
