435 lines
12 KiB
Plaintext
435 lines
12 KiB
Plaintext
#
|
|
# 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 KPROBES_ON_FTRACE
|
|
def_bool y
|
|
depends on KPROBES && HAVE_KPROBES_ON_FTRACE
|
|
depends on DYNAMIC_FTRACE_WITH_REGS
|
|
help
|
|
If function tracer is enabled and the arch supports full
|
|
passing of pt_regs to function tracing, then kprobes can
|
|
optimize on top of function tracing.
|
|
|
|
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_64BIT_ALIGNED_ACCESS
|
|
def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
|
|
help
|
|
Some architectures require 64 bit accesses to be 64 bit
|
|
aligned, which also requires structs containing 64 bit values
|
|
to be 64 bit aligned too. This includes some 32 bit
|
|
architectures which can do 64 bit accesses, as well as 64 bit
|
|
architectures without unaligned access.
|
|
|
|
This symbol should be selected by an architecture if 64 bit
|
|
accesses are required to be 64 bit aligned in this way even
|
|
though it is not a 64 bit architecture.
|
|
|
|
See Documentation/unaligned-memory-access.txt for more
|
|
information on the topic of unaligned memory accesses.
|
|
|
|
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_KPROBES_ON_FTRACE
|
|
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_VIRT_TO_BUS
|
|
bool
|
|
help
|
|
An architecture should select this if it implements the
|
|
deprecated interface virt_to_bus(). All new architectures
|
|
should probably not select this.
|
|
|
|
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.
|
|
|
|
#
|
|
# 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.
|
|
|
|
config ODD_RT_SIGACTION
|
|
bool
|
|
help
|
|
Architecture has unusual rt_sigaction(2) arguments
|
|
|
|
config OLD_SIGSUSPEND
|
|
bool
|
|
help
|
|
Architecture has old sigsuspend(2) syscall, of one-argument variety
|
|
|
|
config OLD_SIGSUSPEND3
|
|
bool
|
|
help
|
|
Even weirder antique ABI - three-argument sigsuspend(2)
|
|
|
|
config OLD_SIGACTION
|
|
bool
|
|
help
|
|
Architecture has old sigaction(2) syscall. Nope, not the same
|
|
as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
|
|
but fairly different variant of sigaction(2), thanks to OSF/1
|
|
compatibility...
|
|
|
|
config COMPAT_OLD_SIGACTION
|
|
bool
|
|
|
|
source "kernel/gcov/Kconfig"
|