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Diffstat (limited to 'kernel/arch/Kconfig')
| -rw-r--r-- | kernel/arch/Kconfig | 549 |
1 files changed, 549 insertions, 0 deletions
diff --git a/kernel/arch/Kconfig b/kernel/arch/Kconfig new file mode 100644 index 000000000..cb27d367b --- /dev/null +++ b/kernel/arch/Kconfig @@ -0,0 +1,549 @@ +# +# General architecture dependent options +# + +config OPROFILE + tristate "OProfile system profiling" + depends on PROFILING + depends on HAVE_OPROFILE + depends on !PREEMPT_RT_FULL + 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 && !PPC64 + +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 + def_bool 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. ) + +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 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 GENERIC_SMP_IDLE_THREAD + bool + +config GENERIC_IDLE_POLL_SETUP + 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_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. + - seccomp syscall wired up + + For best performance, an arch should use seccomp_phase1 and + seccomp_phase2 directly. It should call seccomp_phase1 for all + syscalls if TIF_SECCOMP is set, but seccomp_phase1 does not + need to be called from a ptrace-safe context. It must then + call seccomp_phase2 if seccomp_phase1 returns anything other + than SECCOMP_PHASE1_OK or SECCOMP_PHASE1_SKIP. + + As an additional optimization, an arch may provide seccomp_data + directly to seccomp_phase1; this avoids multiple calls + to the syscall_xyz helpers for every syscall. + +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_CC_STACKPROTECTOR + bool + help + An arch should select this symbol if: + - its compiler supports the -fstack-protector option + - it has implemented a stack canary (e.g. __stack_chk_guard) + +config CC_STACKPROTECTOR + def_bool n + help + Set when a stack-protector mode is enabled, so that the build + can enable kernel-side support for the GCC feature. + +choice + prompt "Stack Protector buffer overflow detection" + depends on HAVE_CC_STACKPROTECTOR + default CC_STACKPROTECTOR_NONE + help + This option turns on the "stack-protector" GCC feature. This + feature puts, at the beginning of functions, a canary value on + the stack just before the return address, and validates + the value just before actually returning. Stack based buffer + overflows (that need to overwrite this return address) now also + overwrite the canary, which gets detected and the attack is then + neutralized via a kernel panic. + +config CC_STACKPROTECTOR_NONE + bool "None" + help + Disable "stack-protector" GCC feature. + +config CC_STACKPROTECTOR_REGULAR + bool "Regular" + select CC_STACKPROTECTOR + help + Functions will have the stack-protector canary logic added if they + have an 8-byte or larger character array on the stack. + + This feature requires gcc version 4.2 or above, or a distribution + gcc with the feature backported ("-fstack-protector"). + + On an x86 "defconfig" build, this feature adds canary checks to + about 3% of all kernel functions, which increases kernel code size + by about 0.3%. + +config CC_STACKPROTECTOR_STRONG + bool "Strong" + select CC_STACKPROTECTOR + help + Functions will have the stack-protector canary logic added in any + of the following conditions: + + - local variable's address used as part of the right hand side of an + assignment or function argument + - local variable is an array (or union containing an array), + regardless of array type or length + - uses register local variables + + This feature requires gcc version 4.9 or above, or a distribution + gcc with the feature backported ("-fstack-protector-strong"). + + On an x86 "defconfig" build, this feature adds canary checks to + about 20% of all kernel functions, which increases the kernel code + size by about 2%. + +endchoice + +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_VIRT_CPU_ACCOUNTING_GEN + bool + default y if 64BIT + help + With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. + Before enabling this option, arch code must be audited + to ensure there are no races in concurrent read/write of + cputime_t. For example, reading/writing 64-bit cputime_t on + some 32-bit arches may require multiple accesses, so proper + locking is needed to protect against concurrent accesses. + + +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_ARCH_HUGE_VMAP + bool + +config HAVE_ARCH_SOFT_DIRTY + 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 HAVE_UNDERSCORE_SYMBOL_PREFIX + bool + help + Some architectures generate an _ in front of C symbols; things like + module loading and assembly files need to know about this. + +config HAVE_IRQ_EXIT_ON_IRQ_STACK + bool + help + Architecture doesn't only execute the irq handler on the irq stack + but also irq_exit(). This way we can process softirqs on this irq + stack instead of switching to a new one when we call __do_softirq() + in the end of an hardirq. + This spares a stack switch and improves cache usage on softirq + processing. + +config PGTABLE_LEVELS + int + default 2 + +config ARCH_HAS_ELF_RANDOMIZE + bool + help + An architecture supports choosing randomized locations for + stack, mmap, brk, and ET_DYN. Defined functions: + - arch_mmap_rnd() + - arch_randomize_brk() + +# +# 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 CLONE_BACKWARDS3 + bool + help + Architecture has tls passed as the 3rd argument of clone(2), + not the 5th one. + +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" |