config [31mCONFIG_ARCH[0m
string
option env="ARCH"
config [31mCONFIG_KERNELVERSION[0m
string
option env="KERNELVERSION"
config [31mCONFIG_DEFCONFIG_LIST[0m
string
depends on ![31mCONFIG_UML[0m
option defconfig_list
default "/lib/modules/$UNAME_RELEASE/.config"
default "/etc/kernel-config"
default "/boot/config-$UNAME_RELEASE"
default "$ARCH_DEFCONFIG"
default "arch/$ARCH/defconfig"
config [31mCONFIG_CONSTRUCTORS[0m
bool
depends on ![31mCONFIG_UML[0m
config [31mCONFIG_IRQ_WORK[0m
bool
config [31mCONFIG_BUILDTIME_EXTABLE_SORT[0m
bool
config [31mCONFIG_THREAD_INFO_IN_TASK[0m
bool
help
Select this to move thread_info off the stack into task_struct. To
make this work, an arch will need to remove all thread_info fields
except flags and fix any runtime bugs.
One subtle change that will be needed is to use try_get_task_stack()
and put_task_stack() in save_thread_stack_tsk() and get_wchan().
menu "General setup"
config [31mCONFIG_BROKEN[0m
bool
config [31mCONFIG_BROKEN_ON_SMP[0m
bool
depends on [31mCONFIG_BROKEN[0m || ![31mCONFIG_SMP[0m
default y
config [31mCONFIG_INIT_ENV_ARG_LIMIT[0m
int
default 32 if ![31mCONFIG_UML[0m
default 128 if [31mCONFIG_UML[0m
help
Maximum of each of the number of arguments and environment
variables passed to init from the kernel command line.
config [31mCONFIG_CROSS_COMPILE[0m
string "Cross-compiler tool prefix"
help
Same as running 'make [31mCONFIG_CROSS_COMPILE[0m=prefix-' but stored for
default make runs in this kernel build directory. You don't
need to set this unless you want the configured kernel build
directory to select the cross-compiler automatically.
config [31mCONFIG_COMPILE_TEST[0m
bool "Compile also drivers which will not load"
depends on ![31mCONFIG_UML[0m
default n
help
Some drivers can be compiled on a different platform than they are
intended to be run on. Despite they cannot be loaded there (or even
when they load they cannot be used due to missing HW support),
developers still, opposing to distributors, might want to build such
drivers to compile-test them.
If you are a developer and want to build everything available, say Y
here. If you are a user/distributor, say N here to exclude useless
drivers to be distributed.
config [31mCONFIG_LOCALVERSION[0m
string "Local version - append to kernel release"
help
Append an extra string to the end of your kernel version.
This will show up when you type uname, for example.
The string you set here will be appended after the contents of
any files with a filename matching localversion* in your
object and source tree, in that order. Your total string can
be a maximum of 64 characters.
config [31mCONFIG_LOCALVERSION_AUTO[0m
bool "Automatically append version information to the version string"
default y
depends on ![31mCONFIG_COMPILE_TEST[0m
help
This will try to automatically determine if the current tree is a
release tree by looking for git tags that belong to the current
top of tree revision.
[31mCONFIG_A[0m string of the format -gxxxxxxxx will be added to the localversion
if a git-based tree is found. The string generated by this will be
appended after any matching localversion* files, and after the value
set in CONFIG_LOCALVERSION.
(The actual string used here is the first eight characters produced
by running the command:
$ git rev-parse --verify HEAD
which is done within the script "scripts/setlocalversion".)
config [31mCONFIG_HAVE_KERNEL_GZIP[0m
bool
config [31mCONFIG_HAVE_KERNEL_BZIP2[0m
bool
config [31mCONFIG_HAVE_KERNEL_LZMA[0m
bool
config [31mCONFIG_HAVE_KERNEL_XZ[0m
bool
config [31mCONFIG_HAVE_KERNEL_LZO[0m
bool
config [31mCONFIG_HAVE_KERNEL_LZ4[0m
bool
choice
prompt "Kernel compression mode"
default [31mCONFIG_KERNEL_GZIP[0m
depends on [31mCONFIG_HAVE_KERNEL_GZIP[0m || [31mCONFIG_HAVE_KERNEL_BZIP2[0m || [31mCONFIG_HAVE_KERNEL_LZMA[0m || [31mCONFIG_HAVE_KERNEL_XZ[0m || [31mCONFIG_HAVE_KERNEL_LZO[0m || [31mCONFIG_HAVE_KERNEL_LZ4[0m
help
The linux kernel is a kind of self-extracting executable.
Several compression algorithms are available, which differ
in efficiency, compression and decompression speed.
Compression speed is only relevant when building a kernel.
Decompression speed is relevant at each boot.
If you have any problems with bzip2 or lzma compressed
kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
version of this functionality (bzip2 only), for 2.4, was
supplied by Christian Ludwig)
High compression options are mostly useful for users, who
are low on disk space (embedded systems), but for whom ram
size matters less.
If in doubt, select 'gzip'
config [31mCONFIG_KERNEL_GZIP[0m
bool "Gzip"
depends on [31mCONFIG_HAVE_KERNEL_GZIP[0m
help
The old and tried gzip compression. It provides a good balance
between compression ratio and decompression speed.
config [31mCONFIG_KERNEL_BZIP2[0m
bool "Bzip2"
depends on [31mCONFIG_HAVE_KERNEL_BZIP2[0m
help
Its compression ratio and speed is intermediate.
Decompression speed is slowest among the choices. The kernel
size is about 10% smaller with bzip2, in comparison to gzip.
Bzip2 uses a large amount of memory. For modern kernels you
will need at least 8MB RAM or more for booting.
config [31mCONFIG_KERNEL_LZMA[0m
bool "LZMA"
depends on [31mCONFIG_HAVE_KERNEL_LZMA[0m
help
This compression algorithm's ratio is best. Decompression speed
is between gzip and bzip2. Compression is slowest.
The kernel size is about 33% smaller with LZMA in comparison to gzip.
config [31mCONFIG_KERNEL_XZ[0m
bool "XZ"
depends on [31mCONFIG_HAVE_KERNEL_XZ[0m
help
XZ uses the LZMA2 algorithm and instruction set specific
BCJ filters which can improve compression ratio of executable
code. The size of the kernel is about 30% smaller with XZ in
comparison to gzip. On architectures for which there is a BCJ
filter (i386, x86_64, [31mCONFIG_ARM[0m, IA-64, PowerPC, and [31mCONFIG_SPARC[0m), XZ
will create a few percent smaller kernel than plain LZMA.
The speed is about the same as with LZMA: The decompression
speed of XZ is better than that of bzip2 but worse than gzip
and LZO. Compression is slow.
config [31mCONFIG_KERNEL_LZO[0m
bool "LZO"
depends on [31mCONFIG_HAVE_KERNEL_LZO[0m
help
Its compression ratio is the poorest among the choices. The kernel
size is about 10% bigger than gzip; however its speed
(both compression and decompression) is the fastest.
config [31mCONFIG_KERNEL_LZ4[0m
bool "LZ4"
depends on [31mCONFIG_HAVE_KERNEL_LZ4[0m
help
LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
[31mCONFIG_A[0m preliminary version of LZ4 de/compression tool is available at
<https://code.google.com/p/lz4/>.
Its compression ratio is worse than LZO. The size of the kernel
is about 8% bigger than LZO. But the decompression speed is
faster than LZO.
endchoice
config [31mCONFIG_DEFAULT_HOSTNAME[0m
string "Default hostname"
default "(none)"
help
This option determines the default system hostname before userspace
calls sethostname(2). The kernel traditionally uses "(none)" here,
but you may wish to use a different default here to make a minimal
system more usable with less configuration.
config [31mCONFIG_SWAP[0m
bool "Support for paging of anonymous memory (swap)"
depends on [31mCONFIG_MMU[0m && [31mCONFIG_BLOCK[0m
default y
help
This option allows you to choose whether you want to have support
for so called swap devices or swap files in your kernel that are
used to provide more virtual memory than the actual RAM present
in your computer. If unsure say Y.
config [31mCONFIG_SYSVIPC[0m
bool "System V IPC"
---help---
Inter Process Communication is a suite of library functions and
system calls which let processes (running programs) synchronize and
exchange information. It is generally considered to be a good thing,
and some programs won't run unless you say Y here. In particular, if
you want to run the DOS emulator dosemu under Linux (read the
DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
you'll need to say Y here.
You can find documentation about IPC with "info ipc" and also in
section 6.4 of the Linux Programmer's Guide, available from
<http://www.tldp.org/guides.html>.
config [31mCONFIG_SYSVIPC_SYSCTL[0m
bool
depends on [31mCONFIG_SYSVIPC[0m
depends on [31mCONFIG_SYSCTL[0m
default y
config [31mCONFIG_POSIX_MQUEUE[0m
bool "POSIX Message Queues"
depends on [31mCONFIG_NET[0m
---help---
POSIX variant of message queues is a part of IPC. In POSIX message
queues every message has a priority which decides about succession
of receiving it by a process. If you want to compile and run
programs written e.g. for Solaris with use of its POSIX message
queues (functions mq_*) say Y here.
POSIX message queues are visible as a filesystem called 'mqueue'
and can be mounted somewhere if you want to do filesystem
operations on message queues.
If unsure, say Y.
config [31mCONFIG_POSIX_MQUEUE_SYSCTL[0m
bool
depends on [31mCONFIG_POSIX_MQUEUE[0m
depends on [31mCONFIG_SYSCTL[0m
default y
config [31mCONFIG_CROSS_MEMORY_ATTACH[0m
bool "Enable process_vm_readv/writev syscalls"
depends on [31mCONFIG_MMU[0m
default y
help
Enabling this option adds the system calls process_vm_readv and
process_vm_writev which allow a process with the correct privileges
to directly read from or write to another process' address space.
See the man page for more details.
config [31mCONFIG_FHANDLE[0m
bool "open by fhandle syscalls" if [31mCONFIG_EXPERT[0m
select [31mCONFIG_EXPORTFS[0m
default y
help
If you say Y here, a user level program will be able to map
file names to handle and then later use the handle for
different file system operations. This is useful in implementing
userspace file servers, which now track files using handles instead
of names. The handle would remain the same even if file names
get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
syscalls.
config [31mCONFIG_USELIB[0m
bool "uselib syscall"
def_bool [31mCONFIG_ALPHA[0m || [31mCONFIG_M68K[0m || [31mCONFIG_SPARC[0m || [31mCONFIG_X86_32[0m || [31mCONFIG_IA32_EMULATION[0m
help
This option enables the uselib syscall, a system call used in the
dynamic linker from libc5 and earlier. glibc does not use this
system call. If you intend to run programs built on libc5 or
earlier, you may need to enable this syscall. Current systems
running glibc can safely disable this.
config [31mCONFIG_AUDIT[0m
bool "Auditing support"
depends on [31mCONFIG_NET[0m
help
Enable auditing infrastructure that can be used with another
kernel subsystem, such as SELinux (which requires this for
logging of avc messages output). System call auditing is included
on architectures which support it.
config [31mCONFIG_HAVE_ARCH_AUDITSYSCALL[0m
bool
config [31mCONFIG_AUDITSYSCALL[0m
def_bool y
depends on [31mCONFIG_AUDIT[0m && [31mCONFIG_HAVE_ARCH_AUDITSYSCALL[0m
config [31mCONFIG_AUDIT_WATCH[0m
def_bool y
depends on [31mCONFIG_AUDITSYSCALL[0m
select [31mCONFIG_FSNOTIFY[0m
config [31mCONFIG_AUDIT_TREE[0m
def_bool y
depends on [31mCONFIG_AUDITSYSCALL[0m
select [31mCONFIG_FSNOTIFY[0m
source "kernel/irq/Kconfig"
source "kernel/time/Kconfig"
menu "CPU/Task time and stats accounting"
config [31mCONFIG_VIRT_CPU_ACCOUNTING[0m
bool
choice
prompt "Cputime accounting"
default [31mCONFIG_TICK_CPU_ACCOUNTING[0m if ![31mCONFIG_PPC64[0m
default [31mCONFIG_VIRT_CPU_ACCOUNTING_NATIVE[0m if [31mCONFIG_PPC64[0m
# Kind of a stub config for the pure tick based cputime accounting
config [31mCONFIG_TICK_CPU_ACCOUNTING[0m
bool "Simple tick based cputime accounting"
depends on ![31mCONFIG_S390[0m && ![31mCONFIG_NO_HZ_FULL[0m
help
This is the basic tick based cputime accounting that maintains
statistics about user, system and idle time spent on per jiffies
granularity.
If unsure, say Y.
config [31mCONFIG_VIRT_CPU_ACCOUNTING_NATIVE[0m
bool "Deterministic task and CPU time accounting"
depends on [31mCONFIG_HAVE_VIRT_CPU_ACCOUNTING[0m && ![31mCONFIG_NO_HZ_FULL[0m
select [31mCONFIG_VIRT_CPU_ACCOUNTING[0m
help
Select this option to enable more accurate task and CPU time
accounting. This is done by reading a CPU counter on each
kernel entry and exit and on transitions within the kernel
between system, softirq and hardirq state, so there is a
small performance impact. In the case of s390 or IBM POWER > 5,
this also enables accounting of stolen time on logically-partitioned
systems.
config [31mCONFIG_VIRT_CPU_ACCOUNTING_GEN[0m
bool "Full dynticks CPU time accounting"
depends on [31mCONFIG_HAVE_CONTEXT_TRACKING[0m
depends on [31mCONFIG_HAVE_VIRT_CPU_ACCOUNTING_GEN[0m
select [31mCONFIG_VIRT_CPU_ACCOUNTING[0m
select [31mCONFIG_CONTEXT_TRACKING[0m
help
Select this option to enable task and CPU time accounting on full
dynticks systems. This accounting is implemented by watching every
kernel-user boundaries using the context tracking subsystem.
The accounting is thus performed at the expense of some significant
overhead.
For now this is only useful if you are working on the full
dynticks subsystem development.
If unsure, say N.
endchoice
config [31mCONFIG_IRQ_TIME_ACCOUNTING[0m
bool "Fine granularity task level IRQ time accounting"
depends on [31mCONFIG_HAVE_IRQ_TIME_ACCOUNTING[0m && ![31mCONFIG_VIRT_CPU_ACCOUNTING_NATIVE[0m
help
Select this option to enable fine granularity task irq time
accounting. This is done by reading a timestamp on each
transitions between softirq and hardirq state, so there can be a
small performance impact.
If in doubt, say N here.
config [31mCONFIG_BSD_PROCESS_ACCT[0m
bool "BSD Process Accounting"
depends on [31mCONFIG_MULTIUSER[0m
help
If you say Y here, a user level program will be able to instruct the
kernel (via a special system call) to write process accounting
information to a file: whenever a process exits, information about
that process will be appended to the file by the kernel. The
information includes things such as creation time, owning user,
command name, memory usage, controlling terminal etc. (the complete
list is in the struct acct in <file:include/linux/acct.h>). It is
up to the user level program to do useful things with this
information. This is generally a good idea, so say Y.
config [31mCONFIG_BSD_PROCESS_ACCT_V3[0m
bool "BSD Process Accounting version 3 file format"
depends on [31mCONFIG_BSD_PROCESS_ACCT[0m
default n
help
If you say Y here, the process accounting information is written
in a new file format that also logs the process IDs of each
process and it's parent. Note that this file format is incompatible
with previous v0/v1/v2 file formats, so you will need updated tools
for processing it. [31mCONFIG_A[0m preliminary version of these tools is available
at <http://www.gnu.org/software/acct/>.
config [31mCONFIG_TASKSTATS[0m
bool "Export task/process statistics through netlink"
depends on [31mCONFIG_NET[0m
depends on [31mCONFIG_MULTIUSER[0m
default n
help
Export selected statistics for tasks/processes through the
generic netlink interface. Unlike BSD process accounting, the
statistics are available during the lifetime of tasks/processes as
responses to commands. Like BSD accounting, they are sent to user
space on task exit.
Say N if unsure.
config [31mCONFIG_TASK_DELAY_ACCT[0m
bool "Enable per-task delay accounting"
depends on [31mCONFIG_TASKSTATS[0m
select [31mCONFIG_SCHED_INFO[0m
help
Collect information on time spent by a task waiting for system
resources like cpu, synchronous block I/O completion and swapping
in pages. Such statistics can help in setting a task's priorities
relative to other tasks for cpu, io, rss limits etc.
Say N if unsure.
config [31mCONFIG_TASK_XACCT[0m
bool "Enable extended accounting over taskstats"
depends on [31mCONFIG_TASKSTATS[0m
help
Collect extended task accounting data and send the data
to userland for processing over the taskstats interface.
Say N if unsure.
config [31mCONFIG_TASK_IO_ACCOUNTING[0m
bool "Enable per-task storage I/O accounting"
depends on [31mCONFIG_TASK_XACCT[0m
help
Collect information on the number of bytes of storage I/O which this
task has caused.
Say N if unsure.
endmenu # "CPU/Task time and stats accounting"
menu "RCU Subsystem"
config [31mCONFIG_TREE_RCU[0m
bool
default y if ![31mCONFIG_PREEMPT[0m && [31mCONFIG_SMP[0m
help
This option selects the RCU implementation that is
designed for very large [31mCONFIG_SMP[0m system with hundreds or
thousands of CPUs. It also scales down nicely to
smaller systems.
config [31mCONFIG_PREEMPT_RCU[0m
bool
default y if [31mCONFIG_PREEMPT[0m
help
This option selects the RCU implementation that is
designed for very large [31mCONFIG_SMP[0m systems with hundreds or
thousands of CPUs, but for which real-time response
is also required. It also scales down nicely to
smaller systems.
Select this option if you are unsure.
config [31mCONFIG_TINY_RCU[0m
bool
default y if ![31mCONFIG_PREEMPT[0m && ![31mCONFIG_SMP[0m
help
This option selects the RCU implementation that is
designed for UP systems from which real-time response
is not required. This option greatly reduces the
memory footprint of RCU.
config [31mCONFIG_RCU_EXPERT[0m
bool "Make expert-level adjustments to RCU configuration"
default n
help
This option needs to be enabled if you wish to make
expert-level adjustments to RCU configuration. By default,
no such adjustments can be made, which has the often-beneficial
side-effect of preventing "make oldconfig" from asking you all
sorts of detailed questions about how you would like numerous
obscure RCU options to be set up.
Say Y if you need to make expert-level adjustments to RCU.
Say N if you are unsure.
config [31mCONFIG_SRCU[0m
bool
help
This option selects the sleepable version of RCU. This version
permits arbitrary sleeping or blocking within RCU read-side critical
sections.
config [31mCONFIG_TASKS_RCU[0m
bool
default n
depends on ![31mCONFIG_UML[0m
select [31mCONFIG_SRCU[0m
help
This option enables a task-based RCU implementation that uses
only voluntary context switch (not preemption!), idle, and
user-mode execution as quiescent states.
config [31mCONFIG_RCU_STALL_COMMON[0m
def_bool ( [31mCONFIG_TREE_RCU[0m || [31mCONFIG_PREEMPT_RCU[0m || [31mCONFIG_RCU_TRACE[0m )
help
This option enables RCU CPU stall code that is common between
the TINY and TREE variants of RCU. The purpose is to allow
the tiny variants to disable RCU CPU stall warnings, while
making these warnings mandatory for the tree variants.
config [31mCONFIG_CONTEXT_TRACKING[0m
bool
config [31mCONFIG_CONTEXT_TRACKING_FORCE[0m
bool "Force context tracking"
depends on [31mCONFIG_CONTEXT_TRACKING[0m
default y if ![31mCONFIG_NO_HZ_FULL[0m
help
The major pre-requirement for full dynticks to work is to
support the context tracking subsystem. But there are also
other dependencies to provide in order to make the full
dynticks working.
This option stands for testing when an arch implements the
context tracking backend but doesn't yet fullfill all the
requirements to make the full dynticks feature working.
Without the full dynticks, there is no way to test the support
for context tracking and the subsystems that rely on it: RCU
userspace extended quiescent state and tickless cputime
accounting. This option copes with the absence of the full
dynticks subsystem by forcing the context tracking on all
CPUs in the system.
Say Y only if you're working on the development of an
architecture backend for the context tracking.
Say N otherwise, this option brings an overhead that you
don't want in production.
config [31mCONFIG_RCU_FANOUT[0m
int "Tree-based hierarchical RCU fanout value"
range 2 64 if [31mCONFIG_64BIT[0m
range 2 32 if ![31mCONFIG_64BIT[0m
depends on ([31mCONFIG_TREE_RCU[0m || [31mCONFIG_PREEMPT_RCU[0m) && [31mCONFIG_RCU_EXPERT[0m
default 64 if [31mCONFIG_64BIT[0m
default 32 if ![31mCONFIG_64BIT[0m
help
This option controls the fanout of hierarchical implementations
of RCU, allowing RCU to work efficiently on machines with
large numbers of CPUs. This value must be at least the fourth
root of [31mCONFIG_NR_CPUS[0m, which allows [31mCONFIG_NR_CPUS[0m to be insanely large.
The default value of [31mCONFIG_RCU_FANOUT[0m should be used for production
systems, but if you are stress-testing the RCU implementation
itself, small [31mCONFIG_RCU_FANOUT[0m values allow you to test large-system
code paths on small(er) systems.
Select a specific number if testing RCU itself.
Take the default if unsure.
config [31mCONFIG_RCU_FANOUT_LEAF[0m
int "Tree-based hierarchical RCU leaf-level fanout value"
range 2 64 if [31mCONFIG_64BIT[0m
range 2 32 if ![31mCONFIG_64BIT[0m
depends on ([31mCONFIG_TREE_RCU[0m || [31mCONFIG_PREEMPT_RCU[0m) && [31mCONFIG_RCU_EXPERT[0m
default 16
help
This option controls the leaf-level fanout of hierarchical
implementations of RCU, and allows trading off cache misses
against lock contention. Systems that synchronize their
scheduling-clock interrupts for energy-efficiency reasons will
want the default because the smaller leaf-level fanout keeps
lock contention levels acceptably low. Very large systems
(hundreds or thousands of CPUs) will instead want to set this
value to the maximum value possible in order to reduce the
number of cache misses incurred during RCU's grace-period
initialization. These systems tend to run CPU-bound, and thus
are not helped by synchronized interrupts, and thus tend to
skew them, which reduces lock contention enough that large
leaf-level fanouts work well.
Select a specific number if testing RCU itself.
Select the maximum permissible value for large systems.
Take the default if unsure.
config [31mCONFIG_RCU_FAST_NO_HZ[0m
bool "Accelerate last non-dyntick-idle CPU's grace periods"
depends on [31mCONFIG_NO_HZ_COMMON[0m && [31mCONFIG_SMP[0m && [31mCONFIG_RCU_EXPERT[0m
default n
help
This option permits CPUs to enter dynticks-idle state even if
they have RCU callbacks queued, and prevents RCU from waking
these CPUs up more than roughly once every four jiffies (by
default, you can adjust this using the rcutree.rcu_idle_gp_delay
parameter), thus improving energy efficiency. On the other
hand, this option increases the duration of RCU grace periods,
for example, slowing down synchronize_rcu().
Say Y if energy efficiency is critically important, and you
don't care about increased grace-period durations.
Say N if you are unsure.
config [31mCONFIG_TREE_RCU_TRACE[0m
def_bool [31mCONFIG_RCU_TRACE[0m && ( [31mCONFIG_TREE_RCU[0m || [31mCONFIG_PREEMPT_RCU[0m )
select [31mCONFIG_DEBUG_FS[0m
help
This option provides tracing for the [31mCONFIG_TREE_RCU[0m and
[31mCONFIG_PREEMPT_RCU[0m implementations, permitting Makefile to
trivially select kernel/rcutree_trace.c.
config [31mCONFIG_RCU_BOOST[0m
bool "Enable RCU priority boosting"
depends on [31mCONFIG_RT_MUTEXES[0m && [31mCONFIG_PREEMPT_RCU[0m && [31mCONFIG_RCU_EXPERT[0m
default n
help
This option boosts the priority of preempted RCU readers that
block the current preemptible RCU grace period for too long.
This option also prevents heavy loads from blocking RCU
callback invocation for all flavors of RCU.
Say Y here if you are working with real-time apps or heavy loads
Say N here if you are unsure.
config [31mCONFIG_RCU_KTHREAD_PRIO[0m
int "Real-time priority to use for RCU worker threads"
range 1 99 if [31mCONFIG_RCU_BOOST[0m
range 0 99 if ![31mCONFIG_RCU_BOOST[0m
default 1 if [31mCONFIG_RCU_BOOST[0m
default 0 if ![31mCONFIG_RCU_BOOST[0m
depends on [31mCONFIG_RCU_EXPERT[0m
help
This option specifies the SCHED_FIFO priority value that will be
assigned to the rcuc/n and rcub/n threads and is also the value
used for [31mCONFIG_RCU_BOOST[0m (if enabled). If you are working with a
real-time application that has one or more CPU-bound threads
running at a real-time priority level, you should set
[31mCONFIG_RCU_KTHREAD_PRIO[0m to a priority higher than the highest-priority
real-time CPU-bound application thread. The default [31mCONFIG_RCU_KTHREAD_PRIO[0m
value of 1 is appropriate in the common case, which is real-time
applications that do not have any CPU-bound threads.
Some real-time applications might not have a single real-time
thread that saturates a given CPU, but instead might have
multiple real-time threads that, taken together, fully utilize
that CPU. In this case, you should set [31mCONFIG_RCU_KTHREAD_PRIO[0m to
a priority higher than the lowest-priority thread that is
conspiring to prevent the CPU from running any non-real-time
tasks. For example, if one thread at priority 10 and another
thread at priority 5 are between themselves fully consuming
the CPU time on a given CPU, then [31mCONFIG_RCU_KTHREAD_PRIO[0m should be
set to priority 6 or higher.
Specify the real-time priority, or take the default if unsure.
config [31mCONFIG_RCU_BOOST_DELAY[0m
int "Milliseconds to delay boosting after RCU grace-period start"
range 0 3000
depends on [31mCONFIG_RCU_BOOST[0m
default 500
help
This option specifies the time to wait after the beginning of
a given grace period before priority-boosting preempted RCU
readers blocking that grace period. Note that any RCU reader
blocking an expedited RCU grace period is boosted immediately.
Accept the default if unsure.
config [31mCONFIG_RCU_NOCB_CPU[0m
bool "Offload RCU callback processing from boot-selected CPUs"
depends on [31mCONFIG_TREE_RCU[0m || [31mCONFIG_PREEMPT_RCU[0m
depends on [31mCONFIG_RCU_EXPERT[0m || [31mCONFIG_NO_HZ_FULL[0m
default n
help
Use this option to reduce OS jitter for aggressive HPC or
real-time workloads. It can also be used to offload RCU
callback invocation to energy-efficient CPUs in battery-powered
asymmetric multiprocessors.
This option offloads callback invocation from the set of
CPUs specified at boot time by the rcu_nocbs parameter.
For each such CPU, a kthread ("rcuox/N") will be created to
invoke callbacks, where the "N" is the CPU being offloaded,
and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
"s" for RCU-sched. Nothing prevents this kthread from running
on the specified CPUs, but (1) the kthreads may be preempted
between each callback, and (2) affinity or cgroups can be used
to force the kthreads to run on whatever set of CPUs is desired.
Say Y here if you want to help to debug reduced OS jitter.
Say N here if you are unsure.
choice
prompt "Build-forced no-CBs CPUs"
default [31mCONFIG_RCU_NOCB_CPU_NONE[0m
depends on [31mCONFIG_RCU_NOCB_CPU[0m
help
This option allows no-CBs CPUs (whose RCU callbacks are invoked
from kthreads rather than from softirq context) to be specified
at build time. Additional no-CBs CPUs may be specified by
the rcu_nocbs= boot parameter.
config [31mCONFIG_RCU_NOCB_CPU_NONE[0m
bool "No build_forced no-CBs CPUs"
help
This option does not force any of the CPUs to be no-CBs CPUs.
Only CPUs designated by the rcu_nocbs= boot parameter will be
no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
kthreads whose names begin with "rcuo". All other CPUs will
invoke their own RCU callbacks in softirq context.
Select this option if you want to choose no-CBs CPUs at
boot time, for example, to allow testing of different no-CBs
configurations without having to rebuild the kernel each time.
config [31mCONFIG_RCU_NOCB_CPU_ZERO[0m
bool "CPU 0 is a build_forced no-CBs CPU"
help
This option forces CPU 0 to be a no-CBs CPU, so that its RCU
callbacks are invoked by a per-CPU kthread whose name begins
with "rcuo". Additional CPUs may be designated as no-CBs
CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
All other CPUs will invoke their own RCU callbacks in softirq
context.
Select this if CPU 0 needs to be a no-CBs CPU for real-time
or energy-efficiency reasons, but the real reason it exists
is to ensure that randconfig testing covers mixed systems.
config [31mCONFIG_RCU_NOCB_CPU_ALL[0m
bool "All CPUs are build_forced no-CBs CPUs"
help
This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
boot parameter will be ignored. All CPUs' RCU callbacks will
be executed in the context of per-CPU rcuo kthreads created for
this purpose. Assuming that the kthreads whose names start with
"rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
on the remaining CPUs, but might decrease memory locality during
RCU-callback invocation, thus potentially degrading throughput.
Select this if all CPUs need to be no-CBs CPUs for real-time
or energy-efficiency reasons.
endchoice
config [31mCONFIG_RCU_EXPEDITE_BOOT[0m
bool
default n
help
This option enables expedited grace periods at boot time,
as if rcu_expedite_gp() had been invoked early in boot.
The corresponding rcu_unexpedite_gp() is invoked from
rcu_end_inkernel_boot(), which is intended to be invoked
at the end of the kernel-only boot sequence, just before
init is exec'ed.
Accept the default if unsure.
endmenu # "RCU Subsystem"
config [31mCONFIG_BUILD_BIN2C[0m
bool
default n
config [31mCONFIG_IKCONFIG[0m
tristate "Kernel .config support"
select [31mCONFIG_BUILD_BIN2C[0m
---help---
This option enables the complete Linux kernel ".config" file
contents to be saved in the kernel. It provides documentation
of which kernel options are used in a running kernel or in an
on-disk kernel. This information can be extracted from the kernel
image file with the script scripts/extract-ikconfig and used as
input to rebuild the current kernel or to build another kernel.
It can also be extracted from a running kernel by reading
/proc/config.gz if enabled (below).
config [31mCONFIG_IKCONFIG_PROC[0m
bool "Enable access to .config through /proc/config.gz"
depends on [31mCONFIG_IKCONFIG[0m && [31mCONFIG_PROC_FS[0m
---help---
This option enables access to the kernel configuration file
through /proc/config.gz.
config [31mCONFIG_LOG_BUF_SHIFT[0m
int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
range 12 25
default 17
depends on [31mCONFIG_PRINTK[0m
help
Select the minimal kernel log buffer size as a power of 2.
The final size is affected by [31mCONFIG_LOG_CPU_MAX_BUF_SHIFT[0m config
parameter, see below. Any higher size also might be forced
by "log_buf_len" boot parameter.
Examples:
17 => 128 KB
16 => 64 KB
15 => 32 KB
14 => 16 KB
13 => 8 KB
12 => 4 KB
config [31mCONFIG_LOG_CPU_MAX_BUF_SHIFT[0m
int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
depends on [31mCONFIG_SMP[0m
range 0 21
default 12 if ![31mCONFIG_BASE_SMALL[0m
default 0 if [31mCONFIG_BASE_SMALL[0m
depends on [31mCONFIG_PRINTK[0m
help
This option allows to increase the default ring buffer size
according to the number of CPUs. The value defines the contribution
of each CPU as a power of 2. The used space is typically only few
lines however it might be much more when problems are reported,
e.g. backtraces.
The increased size means that a new buffer has to be allocated and
the original static one is unused. It makes sense only on systems
with more CPUs. Therefore this value is used only when the sum of
contributions is greater than the half of the default kernel ring
buffer as defined by [31mCONFIG_LOG_BUF_SHIFT[0m. The default values are set
so that more than 64 CPUs are needed to trigger the allocation.
Also this option is ignored when "log_buf_len" kernel parameter is
used as it forces an exact (power of two) size of the ring buffer.
The number of possible CPUs is used for this computation ignoring
hotplugging making the computation optimal for the worst case
scenario while allowing a simple algorithm to be used from bootup.
Examples shift values and their meaning:
17 => 128 KB for each CPU
16 => 64 KB for each CPU
15 => 32 KB for each CPU
14 => 16 KB for each CPU
13 => 8 KB for each CPU
12 => 4 KB for each CPU
config [31mCONFIG_NMI_LOG_BUF_SHIFT[0m
int "Temporary per-CPU NMI log buffer size (12 => 4KB, 13 => 8KB)"
range 10 21
default 13
depends on [31mCONFIG_PRINTK_NMI[0m
help
Select the size of a per-CPU buffer where NMI messages are temporary
stored. They are copied to the main log buffer in a safe context
to avoid a deadlock. The value defines the size as a power of 2.
NMI messages are rare and limited. The largest one is when
a backtrace is printed. It usually fits into 4KB. Select
8KB if you want to be on the safe side.
Examples:
17 => 128 KB for each CPU
16 => 64 KB for each CPU
15 => 32 KB for each CPU
14 => 16 KB for each CPU
13 => 8 KB for each CPU
12 => 4 KB for each CPU
#
# Architectures with an unreliable sched_clock() should select this:
#
config [31mCONFIG_HAVE_UNSTABLE_SCHED_CLOCK[0m
bool
config [31mCONFIG_GENERIC_SCHED_CLOCK[0m
bool
#
# For architectures that want to enable the support for [31mCONFIG_NUMA[0m-affine scheduler
# balancing logic:
#
config [31mCONFIG_ARCH_SUPPORTS_NUMA_BALANCING[0m
bool
#
# For architectures that prefer to flush all TLBs after a number of pages
# are unmapped instead of sending one IPI per page to flush. The architecture
# must provide guarantees on what happens if a clean TLB cache entry is
# written after the unmap. Details are in mm/rmap.c near the check for
# should_defer_flush. The architecture should also consider if the full flush
# and the refill costs are offset by the savings of sending fewer IPIs.
config [31mCONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH[0m
bool
#
# For architectures that know their GCC __int128 support is sound
#
config [31mCONFIG_ARCH_SUPPORTS_INT128[0m
bool
# For architectures that (ab)use [31mCONFIG_NUMA[0m to represent different memory regions
# all cpu-local but of different latencies, such as SuperH.
#
config [31mCONFIG_ARCH_WANT_NUMA_VARIABLE_LOCALITY[0m
bool
config [31mCONFIG_NUMA_BALANCING[0m
bool "Memory placement aware NUMA scheduler"
depends on [31mCONFIG_ARCH_SUPPORTS_NUMA_BALANCING[0m
depends on ![31mCONFIG_ARCH_WANT_NUMA_VARIABLE_LOCALITY[0m
depends on [31mCONFIG_SMP[0m && [31mCONFIG_NUMA[0m && [31mCONFIG_MIGRATION[0m
help
This option adds support for automatic [31mCONFIG_NUMA[0m aware memory/task placement.
The mechanism is quite primitive and is based on migrating memory when
it has references to the node the task is running on.
This system will be inactive on UMA systems.
config [31mCONFIG_NUMA_BALANCING_DEFAULT_ENABLED[0m
bool "Automatically enable NUMA aware memory/task placement"
default y
depends on [31mCONFIG_NUMA_BALANCING[0m
help
If set, automatic [31mCONFIG_NUMA[0m balancing will be enabled if running on a [31mCONFIG_NUMA[0m
machine.
menuconfig [31mCONFIG_CGROUPS[0m
bool "Control Group support"
select [31mCONFIG_KERNFS[0m
help
This option adds support for grouping sets of processes together, for
use with process control subsystems such as Cpusets, CFS, memory
controls or device isolation.
See
- Documentation/scheduler/sched-design-CFS.txt (CFS)
- Documentation/cgroup-v1/ (features for grouping, isolation
and resource control)
Say N if unsure.
if [31mCONFIG_CGROUPS[0m
config [31mCONFIG_PAGE_COUNTER[0m
bool
config [31mCONFIG_MEMCG[0m
bool "Memory controller"
select [31mCONFIG_PAGE_COUNTER[0m
select [31mCONFIG_EVENTFD[0m
help
Provides control over the memory footprint of tasks in a cgroup.
config [31mCONFIG_MEMCG_SWAP[0m
bool "Swap controller"
depends on [31mCONFIG_MEMCG[0m && [31mCONFIG_SWAP[0m
help
Provides control over the swap space consumed by tasks in a cgroup.
config [31mCONFIG_MEMCG_SWAP_ENABLED[0m
bool "Swap controller enabled by default"
depends on [31mCONFIG_MEMCG_SWAP[0m
default y
help
Memory Resource Controller Swap Extension comes with its price in
a bigger memory consumption. General purpose distribution kernels
which want to enable the feature but keep it disabled by default
and let the user enable it by swapaccount=1 boot command line
parameter should have this option unselected.
For those who want to have the feature enabled by default should
select this option (if, for some reason, they need to disable it
then swapaccount=0 does the trick).
config [31mCONFIG_BLK_CGROUP[0m
bool "IO controller"
depends on [31mCONFIG_BLOCK[0m
default n
---help---
Generic block IO controller cgroup interface. This is the common
cgroup interface which should be used by various IO controlling
policies.
Currently, CFQ IO scheduler uses it to recognize task groups and
control disk bandwidth allocation (proportional time slice allocation)
to such task groups. It is also used by bio throttling logic in
block layer to implement upper limit in IO rates on a device.
This option only enables generic Block IO controller infrastructure.
One needs to also enable actual IO controlling logic/policy. For
enabling proportional weight division of disk bandwidth in CFQ, set
CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
CONFIG_BLK_DEV_THROTTLING=y.
See Documentation/cgroup-v1/blkio-controller.txt for more information.
config [31mCONFIG_DEBUG_BLK_CGROUP[0m
bool "IO controller debugging"
depends on [31mCONFIG_BLK_CGROUP[0m
default n
---help---
Enable some debugging help. Currently it exports additional stat
files in a cgroup which can be useful for debugging.
config [31mCONFIG_CGROUP_WRITEBACK[0m
bool
depends on [31mCONFIG_MEMCG[0m && [31mCONFIG_BLK_CGROUP[0m
default y
menuconfig [31mCONFIG_CGROUP_SCHED[0m
bool "CPU controller"
default n
help
This feature lets CPU scheduler recognize task groups and control CPU
bandwidth allocation to such task groups. It uses cgroups to group
tasks.
if [31mCONFIG_CGROUP_SCHED[0m
config [31mCONFIG_FAIR_GROUP_SCHED[0m
bool "Group scheduling for SCHED_OTHER"
depends on [31mCONFIG_CGROUP_SCHED[0m
default [31mCONFIG_CGROUP_SCHED[0m
config [31mCONFIG_CFS_BANDWIDTH[0m
bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
depends on [31mCONFIG_FAIR_GROUP_SCHED[0m
default n
help
This option allows users to define CPU bandwidth rates (limits) for
tasks running within the fair group scheduler. Groups with no limit
set are considered to be unconstrained and will run with no
restriction.
See tip/Documentation/scheduler/sched-bwc.txt for more information.
config [31mCONFIG_RT_GROUP_SCHED[0m
bool "Group scheduling for SCHED_RR/FIFO"
depends on [31mCONFIG_CGROUP_SCHED[0m
default n
help
This feature lets you explicitly allocate real CPU bandwidth
to task groups. If enabled, it will also make it impossible to
schedule realtime tasks for non-root users until you allocate
realtime bandwidth for them.
See Documentation/scheduler/sched-rt-group.txt for more information.
endif #[31mCONFIG_CGROUP_SCHED[0m
config [31mCONFIG_CGROUP_PIDS[0m
bool "PIDs controller"
help
Provides enforcement of process number limits in the scope of a
cgroup. Any attempt to fork more processes than is allowed in the
cgroup will fail. PIDs are fundamentally a global resource because it
is fairly trivial to reach PID exhaustion before you reach even a
conservative kmemcg limit. As a result, it is possible to grind a
system to halt without being limited by other cgroup policies. The
PIDs controller is designed to stop this from happening.
It should be noted that organisational operations (such as attaching
to a cgroup hierarchy will *not* be blocked by the PIDs controller),
since the PIDs limit only affects a process's ability to fork, not to
attach to a cgroup.
config [31mCONFIG_CGROUP_FREEZER[0m
bool "Freezer controller"
help
Provides a way to freeze and unfreeze all tasks in a
cgroup.
This option affects the ORIGINAL cgroup interface. The cgroup2 memory
controller includes important in-kernel memory consumers per default.
If you're using cgroup2, say N.
config [31mCONFIG_CGROUP_HUGETLB[0m
bool "HugeTLB controller"
depends on [31mCONFIG_HUGETLB_PAGE[0m
select [31mCONFIG_PAGE_COUNTER[0m
default n
help
Provides a cgroup controller for HugeTLB pages.
When you enable this, you can put a per cgroup limit on HugeTLB usage.
The limit is enforced during page fault. Since HugeTLB doesn't
support page reclaim, enforcing the limit at page fault time implies
that, the application will get SIGBUS signal if it tries to access
HugeTLB pages beyond its limit. This requires the application to know
beforehand how much HugeTLB pages it would require for its use. The
control group is tracked in the third page lru pointer. This means
that we cannot use the controller with huge page less than 3 pages.
config [31mCONFIG_CPUSETS[0m
bool "Cpuset controller"
help
This option will let you create and manage CPUSETs which
allow dynamically partitioning a system into sets of CPUs and
Memory Nodes and assigning tasks to run only within those sets.
This is primarily useful on large [31mCONFIG_SMP[0m or [31mCONFIG_NUMA[0m systems.
Say N if unsure.
config [31mCONFIG_PROC_PID_CPUSET[0m
bool "Include legacy /proc/<pid>/cpuset file"
depends on [31mCONFIG_CPUSETS[0m
default y
config [31mCONFIG_CGROUP_DEVICE[0m
bool "Device controller"
help
Provides a cgroup controller implementing whitelists for
devices which a process in the cgroup can mknod or open.
config [31mCONFIG_CGROUP_CPUACCT[0m
bool "Simple CPU accounting controller"
help
Provides a simple controller for monitoring the
total CPU consumed by the tasks in a cgroup.
config [31mCONFIG_CGROUP_PERF[0m
bool "Perf controller"
depends on [31mCONFIG_PERF_EVENTS[0m
help
This option extends the perf per-cpu mode to restrict monitoring
to threads which belong to the cgroup specified and run on the
designated cpu.
Say N if unsure.
config [31mCONFIG_CGROUP_BPF[0m
bool "Support for eBPF programs attached to cgroups"
depends on [31mCONFIG_BPF_SYSCALL[0m
select [31mCONFIG_SOCK_CGROUP_DATA[0m
help
Allow attaching eBPF programs to a cgroup using the bpf(2)
syscall command BPF_PROG_ATTACH.
In which context these programs are accessed depends on the type
of attachment. For instance, programs that are attached using
BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
inet sockets.
config [31mCONFIG_CGROUP_DEBUG[0m
bool "Example controller"
default n
help
This option enables a simple controller that exports
debugging information about the cgroups framework.
Say N.
config [31mCONFIG_SOCK_CGROUP_DATA[0m
bool
default n
endif # [31mCONFIG_CGROUPS[0m
config [31mCONFIG_CHECKPOINT_RESTORE[0m
bool "Checkpoint/restore support" if [31mCONFIG_EXPERT[0m
select [31mCONFIG_PROC_CHILDREN[0m
default n
help
Enables additional kernel features in a sake of checkpoint/restore.
In particular it adds auxiliary prctl codes to setup process text,
data and heap segment sizes, and a few additional /proc filesystem
entries.
If unsure, say N here.
menuconfig [31mCONFIG_NAMESPACES[0m
bool "Namespaces support" if [31mCONFIG_EXPERT[0m
depends on [31mCONFIG_MULTIUSER[0m
default ![31mCONFIG_EXPERT[0m
help
Provides the way to make tasks work with different objects using
the same id. For example same IPC id may refer to different objects
or same user id or pid may refer to different tasks when used in
different namespaces.
if [31mCONFIG_NAMESPACES[0m
config [31mCONFIG_UTS_NS[0m
bool "UTS namespace"
default y
help
In this namespace tasks see different info provided with the
uname() system call
config [31mCONFIG_IPC_NS[0m
bool "IPC namespace"
depends on ([31mCONFIG_SYSVIPC[0m || [31mCONFIG_POSIX_MQUEUE[0m)
default y
help
In this namespace tasks work with IPC ids which correspond to
different IPC objects in different namespaces.
config [31mCONFIG_USER_NS[0m
bool "User namespace"
default n
help
This allows containers, i.e. vservers, to use user namespaces
to provide different user info for different servers.
When user namespaces are enabled in the kernel it is
recommended that the [31mCONFIG_MEMCG[0m option also be enabled and that
user-space use the memory control groups to limit the amount
of memory a memory unprivileged users can use.
If unsure, say N.
config [31mCONFIG_PID_NS[0m
bool "PID Namespaces"
default y
help
Support process id namespaces. This allows having multiple
processes with the same pid as long as they are in different
pid namespaces. This is a building block of containers.
config [31mCONFIG_NET_NS[0m
bool "Network namespace"
depends on [31mCONFIG_NET[0m
default y
help
Allow user space to create what appear to be multiple instances
of the network stack.
endif # [31mCONFIG_NAMESPACES[0m
config [31mCONFIG_SCHED_AUTOGROUP[0m
bool "Automatic process group scheduling"
select [31mCONFIG_CGROUPS[0m
select [31mCONFIG_CGROUP_SCHED[0m
select [31mCONFIG_FAIR_GROUP_SCHED[0m
help
This option optimizes the scheduler for common desktop workloads by
automatically creating and populating task groups. This separation
of workloads isolates aggressive CPU burners (like build jobs) from
desktop applications. Task group autogeneration is currently based
upon task session.
config [31mCONFIG_SYSFS_DEPRECATED[0m
bool "Enable deprecated sysfs features to support old userspace tools"
depends on [31mCONFIG_SYSFS[0m
default n
help
This option adds code that switches the layout of the "block" class
devices, to not show up in /sys/class/block/, but only in
/sys/block/.
This switch is only active when the sysfs.deprecated=1 boot option is
passed or the [31mCONFIG_SYSFS_DEPRECATED_V2[0m option is set.
This option allows new kernels to run on old distributions and tools,
which might get confused by /sys/class/block/. Since 2007/2008 all
major distributions and tools handle this just fine.
Recent distributions and userspace tools after 2009/2010 depend on
the existence of /sys/class/block/, and will not work with this
option enabled.
Only if you are using a new kernel on an old distribution, you might
need to say Y here.
config [31mCONFIG_SYSFS_DEPRECATED_V2[0m
bool "Enable deprecated sysfs features by default"
default n
depends on [31mCONFIG_SYSFS[0m
depends on [31mCONFIG_SYSFS_DEPRECATED[0m
help
Enable deprecated sysfs by default.
See the CONFIG_SYSFS_DEPRECATED option for more details about this
option.
Only if you are using a new kernel on an old distribution, you might
need to say Y here. Even then, odds are you would not need it
enabled, you can always pass the boot option if absolutely necessary.
config [31mCONFIG_RELAY[0m
bool "Kernel->user space relay support (formerly relayfs)"
select [31mCONFIG_IRQ_WORK[0m
help
This option enables support for relay interface support in
certain file systems (such as debugfs).
It is designed to provide an efficient mechanism for tools and
facilities to relay large amounts of data from kernel space to
user space.
If unsure, say N.
config [31mCONFIG_BLK_DEV_INITRD[0m
bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
depends on [31mCONFIG_BROKEN[0m || ![31mCONFIG_FRV[0m
help
The initial RAM filesystem is a ramfs which is loaded by the
boot loader (loadlin or lilo) and that is mounted as root
before the normal boot procedure. It is typically used to
load modules needed to mount the "real" root file system,
etc. See <file:Documentation/admin-guide/initrd.rst> for details.
If RAM disk support ([31mCONFIG_BLK_DEV_RAM[0m) is also included, this
also enables initial RAM disk (initrd) support and adds
15 Kbytes (more on some other architectures) to the kernel size.
If unsure say Y.
if [31mCONFIG_BLK_DEV_INITRD[0m
source "usr/Kconfig"
endif
choice
prompt "Compiler optimization level"
default CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
config [31mCONFIG_CC_OPTIMIZE_FOR_PERFORMANCE[0m
bool "Optimize for performance"
help
This is the default optimization level for the kernel, building
with the "-O2" compiler flag for best performance and most
helpful compile-time warnings.
config [31mCONFIG_CC_OPTIMIZE_FOR_SIZE[0m
bool "Optimize for size"
help
Enabling this option will pass "-Os" instead of "-O2" to
your compiler resulting in a smaller kernel.
If unsure, say N.
endchoice
config [31mCONFIG_SYSCTL[0m
bool
config [31mCONFIG_ANON_INODES[0m
bool
config [31mCONFIG_HAVE_UID16[0m
bool
config [31mCONFIG_SYSCTL_EXCEPTION_TRACE[0m
bool
help
Enable support for /proc/sys/debug/exception-trace.
config [31mCONFIG_SYSCTL_ARCH_UNALIGN_NO_WARN[0m
bool
help
Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
Allows arch to define/use @no_unaligned_warning to possibly warn
about unaligned access emulation going on under the hood.
config [31mCONFIG_SYSCTL_ARCH_UNALIGN_ALLOW[0m
bool
help
Enable support for /proc/sys/kernel/unaligned-trap
Allows arches to define/use @unaligned_enabled to runtime toggle
the unaligned access emulation.
see arch/parisc/kernel/unaligned.c for reference
config [31mCONFIG_HAVE_PCSPKR_PLATFORM[0m
bool
# interpreter that classic socket filters depend on
config [31mCONFIG_BPF[0m
bool
menuconfig [31mCONFIG_EXPERT[0m
bool "Configure standard kernel features (expert users)"
# Unhide debug options, to make the on-by-default options visible
select [31mCONFIG_DEBUG_KERNEL[0m
help
This option allows certain base kernel options and settings
to be disabled or tweaked. This is for specialized
environments which can tolerate a "non-standard" kernel.
Only use this if you really know what you are doing.
config [31mCONFIG_UID16[0m
bool "Enable 16-bit UID system calls" if [31mCONFIG_EXPERT[0m
depends on [31mCONFIG_HAVE_UID16[0m && [31mCONFIG_MULTIUSER[0m
default y
help
This enables the legacy 16-bit UID syscall wrappers.
config [31mCONFIG_MULTIUSER[0m
bool "Multiple users, groups and capabilities support" if [31mCONFIG_EXPERT[0m
default y
help
This option enables support for non-root users, groups and
capabilities.
If you say N here, all processes will run with UID 0, GID 0, and all
possible capabilities. Saying N here also compiles out support for
system calls related to UIDs, GIDs, and capabilities, such as setuid,
setgid, and capset.
If unsure, say Y here.
config [31mCONFIG_SGETMASK_SYSCALL[0m
bool "sgetmask/ssetmask syscalls support" if [31mCONFIG_EXPERT[0m
def_bool [31mCONFIG_PARISC[0m || [31mCONFIG_MN10300[0m || [31mCONFIG_BLACKFIN[0m || [31mCONFIG_M68K[0m || [31mCONFIG_PPC[0m || [31mCONFIG_MIPS[0m || [31mCONFIG_X86[0m || [31mCONFIG_SPARC[0m || [31mCONFIG_CRIS[0m || [31mCONFIG_MICROBLAZE[0m || [31mCONFIG_SUPERH[0m
---help---
sys_sgetmask and sys_ssetmask are obsolete system calls
no longer supported in libc but still enabled by default in some
architectures.
If unsure, leave the default option here.
config [31mCONFIG_SYSFS_SYSCALL[0m
bool "Sysfs syscall support" if [31mCONFIG_EXPERT[0m
default y
---help---
sys_sysfs is an obsolete system call no longer supported in libc.
Note that disabling this option is more secure but might break
compatibility with some systems.
If unsure say Y here.
config [31mCONFIG_SYSCTL_SYSCALL[0m
bool "Sysctl syscall support" if [31mCONFIG_EXPERT[0m
depends on [31mCONFIG_PROC_SYSCTL[0m
default n
select [31mCONFIG_SYSCTL[0m
---help---
sys_sysctl uses binary paths that have been found challenging
to properly maintain and use. The interface in /proc/sys
using paths with ascii names is now the primary path to this
information.
Almost nothing using the binary sysctl interface so if you are
trying to save some space it is probably safe to disable this,
making your kernel marginally smaller.
If unsure say N here.
config [31mCONFIG_POSIX_TIMERS[0m
bool "Posix Clocks & timers" if [31mCONFIG_EXPERT[0m
default y
help
This includes native support for POSIX timers to the kernel.
Some embedded systems have no use for them and therefore they
can be configured out to reduce the size of the kernel image.
When this option is disabled, the following syscalls won't be
available: timer_create, timer_gettime: timer_getoverrun,
timer_settime, timer_delete, clock_adjtime, getitimer,
setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
clock_getres and clock_nanosleep syscalls will be limited to
CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.
If unsure say y.
config [31mCONFIG_KALLSYMS[0m
bool "Load all symbols for debugging/ksymoops" if [31mCONFIG_EXPERT[0m
default y
help
Say Y here to let the kernel print out symbolic crash information and
symbolic stack backtraces. This increases the size of the kernel
somewhat, as all symbols have to be loaded into the kernel image.
config [31mCONFIG_KALLSYMS_ALL[0m
bool "Include all symbols in kallsyms"
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_KALLSYMS[0m
help
Normally kallsyms only contains the symbols of functions for nicer
OOPS messages and backtraces (i.e., symbols from the text and inittext
sections). This is sufficient for most cases. And only in very rare
cases (e.g., when a debugger is used) all symbols are required (e.g.,
names of variables from the data sections, etc).
This option makes sure that all symbols are loaded into the kernel
image (i.e., symbols from all sections) in cost of increased kernel
size (depending on the kernel configuration, it may be 300KiB or
something like this).
Say N unless you really need all symbols.
config [31mCONFIG_KALLSYMS_ABSOLUTE_PERCPU[0m
bool
depends on [31mCONFIG_KALLSYMS[0m
default [31mCONFIG_X86_64[0m && [31mCONFIG_SMP[0m
config [31mCONFIG_KALLSYMS_BASE_RELATIVE[0m
bool
depends on [31mCONFIG_KALLSYMS[0m
default ![31mCONFIG_IA64[0m && !([31mCONFIG_TILE[0m && [31mCONFIG_64BIT[0m)
help
Instead of emitting them as absolute values in the native word size,
emit the symbol references in the kallsyms table as 32-bit entries,
each containing a relative value in the range [base, base + U32_MAX]
or, when [31mCONFIG_KALLSYMS_ABSOLUTE_PERCPU[0m is in effect, each containing either
an absolute value in the range [0, S32_MAX] or a relative value in the
range [base, base + S32_MAX], where base is the lowest relative symbol
address encountered in the image.
On 64-bit builds, this reduces the size of the address table by 50%,
but more importantly, it results in entries whose values are build
time constants, and no relocation pass is required at runtime to fix
up the entries based on the runtime load address of the kernel.
config [31mCONFIG_PRINTK[0m
default y
bool "Enable support for printk" if [31mCONFIG_EXPERT[0m
select [31mCONFIG_IRQ_WORK[0m
help
This option enables normal printk support. Removing it
eliminates most of the message strings from the kernel image
and makes the kernel more or less silent. As this makes it
very difficult to diagnose system problems, saying N here is
strongly discouraged.
config [31mCONFIG_PRINTK_NMI[0m
def_bool y
depends on [31mCONFIG_PRINTK[0m
depends on [31mCONFIG_HAVE_NMI[0m
config [31mCONFIG_BUG[0m
bool "BUG() support" if [31mCONFIG_EXPERT[0m
default y
help
Disabling this option eliminates support for [31mCONFIG_BUG[0m and WARN, reducing
the size of your kernel image and potentially quietly ignoring
numerous fatal conditions. You should only consider disabling this
option for embedded systems with no facilities for reporting errors.
Just say Y.
config [31mCONFIG_ELF_CORE[0m
depends on [31mCONFIG_COREDUMP[0m
default y
bool "Enable ELF core dumps" if [31mCONFIG_EXPERT[0m
help
Enable support for generating core dumps. Disabling saves about 4k.
config [31mCONFIG_PCSPKR_PLATFORM[0m
bool "Enable PC-Speaker support" if [31mCONFIG_EXPERT[0m
depends on [31mCONFIG_HAVE_PCSPKR_PLATFORM[0m
select [31mCONFIG_I8253_LOCK[0m
default y
help
This option allows to disable the internal PC-Speaker
support, saving some memory.
config [31mCONFIG_BASE_FULL[0m
default y
bool "Enable full-sized data structures for core" if [31mCONFIG_EXPERT[0m
help
Disabling this option reduces the size of miscellaneous core
kernel data structures. This saves memory on small machines,
but may reduce performance.
config [31mCONFIG_FUTEX[0m
bool "Enable futex support" if [31mCONFIG_EXPERT[0m
default y
select [31mCONFIG_RT_MUTEXES[0m
help
Disabling this option will cause the kernel to be built without
support for "fast userspace mutexes". The resulting kernel may not
run glibc-based applications correctly.
config [31mCONFIG_HAVE_FUTEX_CMPXCHG[0m
bool
depends on [31mCONFIG_FUTEX[0m
help
Architectures should select this if futex_atomic_cmpxchg_inatomic()
is implemented and always working. This removes a couple of runtime
checks.
config [31mCONFIG_EPOLL[0m
bool "Enable eventpoll support" if [31mCONFIG_EXPERT[0m
default y
select [31mCONFIG_ANON_INODES[0m
help
Disabling this option will cause the kernel to be built without
support for epoll family of system calls.
config [31mCONFIG_SIGNALFD[0m
bool "Enable signalfd() system call" if [31mCONFIG_EXPERT[0m
select [31mCONFIG_ANON_INODES[0m
default y
help
Enable the signalfd() system call that allows to receive signals
on a file descriptor.
If unsure, say Y.
config [31mCONFIG_TIMERFD[0m
bool "Enable timerfd() system call" if [31mCONFIG_EXPERT[0m
select [31mCONFIG_ANON_INODES[0m
default y
help
Enable the timerfd() system call that allows to receive timer
events on a file descriptor.
If unsure, say Y.
config [31mCONFIG_EVENTFD[0m
bool "Enable eventfd() system call" if [31mCONFIG_EXPERT[0m
select [31mCONFIG_ANON_INODES[0m
default y
help
Enable the eventfd() system call that allows to receive both
kernel notification (ie. KAIO) or userspace notifications.
If unsure, say Y.
# syscall, maps, verifier
config [31mCONFIG_BPF_SYSCALL[0m
bool "Enable bpf() system call"
select [31mCONFIG_ANON_INODES[0m
select [31mCONFIG_BPF[0m
default n
help
Enable the bpf() system call that allows to manipulate eBPF
programs and maps via file descriptors.
config [31mCONFIG_SHMEM[0m
bool "Use full shmem filesystem" if [31mCONFIG_EXPERT[0m
default y
depends on [31mCONFIG_MMU[0m
help
The shmem is an internal filesystem used to manage shared memory.
It is backed by swap and manages resource limits. It is also exported
to userspace as tmpfs if [31mCONFIG_TMPFS[0m is enabled. Disabling this
option replaces shmem and tmpfs with the much simpler ramfs code,
which may be appropriate on small systems without swap.
config [31mCONFIG_AIO[0m
bool "Enable AIO support" if [31mCONFIG_EXPERT[0m
default y
help
This option enables POSIX asynchronous I/O which may by used
by some high performance threaded applications. Disabling
this option saves about 7k.
config [31mCONFIG_ADVISE_SYSCALLS[0m
bool "Enable madvise/fadvise syscalls" if [31mCONFIG_EXPERT[0m
default y
help
This option enables the madvise and fadvise syscalls, used by
applications to advise the kernel about their future memory or file
usage, improving performance. If building an embedded system where no
applications use these syscalls, you can disable this option to save
space.
config [31mCONFIG_USERFAULTFD[0m
bool "Enable userfaultfd() system call"
select [31mCONFIG_ANON_INODES[0m
depends on [31mCONFIG_MMU[0m
help
Enable the userfaultfd() system call that allows to intercept and
handle page faults in userland.
config [31mCONFIG_PCI_QUIRKS[0m
default y
bool "Enable PCI quirk workarounds" if [31mCONFIG_EXPERT[0m
depends on [31mCONFIG_PCI[0m
help
This enables workarounds for various [31mCONFIG_PCI[0m chipset
bugs/quirks. Disable this only if your target machine is
unaffected by [31mCONFIG_PCI[0m quirks.
config [31mCONFIG_MEMBARRIER[0m
bool "Enable membarrier() system call" if [31mCONFIG_EXPERT[0m
default y
help
Enable the membarrier() system call that allows issuing memory
barriers across all running threads, which can be used to distribute
the cost of user-space memory barriers asymmetrically by transforming
pairs of memory barriers into pairs consisting of membarrier() and a
compiler barrier.
If unsure, say Y.
config [31mCONFIG_EMBEDDED[0m
bool "Embedded system"
option allnoconfig_y
select [31mCONFIG_EXPERT[0m
help
This option should be enabled if compiling the kernel for
an embedded system so certain expert options are available
for configuration.
config [31mCONFIG_HAVE_PERF_EVENTS[0m
bool
help
See tools/perf/design.txt for details.
config [31mCONFIG_PERF_USE_VMALLOC[0m
bool
help
See tools/perf/design.txt for details
menu "Kernel Performance Events And Counters"
config [31mCONFIG_PERF_EVENTS[0m
bool "Kernel performance events and counters"
default y if [31mCONFIG_PROFILING[0m
depends on [31mCONFIG_HAVE_PERF_EVENTS[0m
select [31mCONFIG_ANON_INODES[0m
select [31mCONFIG_IRQ_WORK[0m
select [31mCONFIG_SRCU[0m
help
Enable kernel support for various performance events provided
by software and hardware.
Software events are supported either built-in or via the
use of generic tracepoints.
Most modern CPUs support performance events via performance
counter registers. These registers count the number of certain
types of hw events: such as instructions executed, cachemisses
suffered, or branches mis-predicted - without slowing down the
kernel or applications. These registers can also trigger interrupts
when a threshold number of events have passed - and can thus be
used to profile the code that runs on that CPU.
The Linux Performance Event subsystem provides an abstraction of
these software and hardware event capabilities, available via a
system call and used by the "perf" utility in tools/perf/. It
provides per task and per CPU counters, and it provides event
capabilities on top of those.
Say Y if unsure.
config [31mCONFIG_DEBUG_PERF_USE_VMALLOC[0m
default n
bool "Debug: use vmalloc to back perf mmap() buffers"
depends on [31mCONFIG_PERF_EVENTS[0m && [31mCONFIG_DEBUG_KERNEL[0m && ![31mCONFIG_PPC[0m
select [31mCONFIG_PERF_USE_VMALLOC[0m
help
Use vmalloc memory to back perf mmap() buffers.
Mostly useful for debugging the vmalloc code on platforms
that don't require it.
Say N if unsure.
endmenu
config [31mCONFIG_VM_EVENT_COUNTERS[0m
default y
bool "Enable VM event counters for /proc/vmstat" if [31mCONFIG_EXPERT[0m
help
VM event counters are needed for event counts to be shown.
This option allows the disabling of the VM event counters
on [31mCONFIG_EXPERT[0m systems. /proc/vmstat will only show page counts
if VM event counters are disabled.
config [31mCONFIG_SLUB_DEBUG[0m
default y
bool "Enable SLUB debugging support" if [31mCONFIG_EXPERT[0m
depends on [31mCONFIG_SLUB[0m && [31mCONFIG_SYSFS[0m
help
[31mCONFIG_SLUB[0m has extensive debug support features. Disabling these can
result in significant savings in code size. This also disables
[31mCONFIG_SLUB[0m sysfs support. /sys/slab will not exist and there will be
no support for cache validation etc.
config [31mCONFIG_COMPAT_BRK[0m
bool "Disable heap randomization"
default y
help
Randomizing heap placement makes heap exploits harder, but it
also breaks ancient binaries (including anything libc5 based).
This option changes the bootup default to heap randomization
disabled, and can be overridden at runtime by setting
/proc/sys/kernel/randomize_va_space to 2.
On non-ancient distros (post-2000 ones) N is usually a safe choice.
choice
prompt "Choose SLAB allocator"
default [31mCONFIG_SLUB[0m
help
This option allows to select a slab allocator.
config [31mCONFIG_SLAB[0m
bool "SLAB"
select [31mCONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR[0m
help
The regular slab allocator that is established and known to work
well in all environments. It organizes cache hot objects in
per cpu and per node queues.
config [31mCONFIG_SLUB[0m
bool "SLUB (Unqueued Allocator)"
select [31mCONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR[0m
help
[31mCONFIG_SLUB[0m is a slab allocator that minimizes cache line usage
instead of managing queues of cached objects ([31mCONFIG_SLAB[0m approach).
Per cpu caching is realized using slabs of objects instead
of queues of objects. [31mCONFIG_SLUB[0m can use memory efficiently
and has enhanced diagnostics. [31mCONFIG_SLUB[0m is the default choice for
a slab allocator.
config [31mCONFIG_SLOB[0m
depends on [31mCONFIG_EXPERT[0m
bool "SLOB (Simple Allocator)"
help
[31mCONFIG_SLOB[0m replaces the stock allocator with a drastically simpler
allocator. [31mCONFIG_SLOB[0m is generally more space efficient but
does not perform as well on large systems.
endchoice
config [31mCONFIG_SLAB_FREELIST_RANDOM[0m
default n
depends on [31mCONFIG_SLAB[0m || [31mCONFIG_SLUB[0m
bool "SLAB freelist randomization"
help
Randomizes the freelist order used on creating new pages. This
security feature reduces the predictability of the kernel slab
allocator against heap overflows.
config [31mCONFIG_SLUB_CPU_PARTIAL[0m
default y
depends on [31mCONFIG_SLUB[0m && [31mCONFIG_SMP[0m
bool "SLUB per cpu partial cache"
help
Per cpu partial caches accellerate objects allocation and freeing
that is local to a processor at the price of more indeterminism
in the latency of the free. On overflow these caches will be cleared
which requires the taking of locks that may cause latency spikes.
Typically one would choose no for a realtime system.
config [31mCONFIG_MMAP_ALLOW_UNINITIALIZED[0m
bool "Allow mmapped anonymous memory to be uninitialized"
depends on [31mCONFIG_EXPERT[0m && ![31mCONFIG_MMU[0m
default n
help
Normally, and according to the Linux spec, anonymous memory obtained
from mmap() has it's contents cleared before it is passed to
userspace. Enabling this config option allows you to request that
mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
providing a huge performance boost. If this option is not enabled,
then the flag will be ignored.
This is taken advantage of by uClibc's malloc(), and also by
ELF-FDPIC binfmt's brk and stack allocator.
Because of the obvious security issues, this option should only be
enabled on embedded devices where you control what is run in
userspace. Since that isn't generally a problem on no-[31mCONFIG_MMU[0m systems,
it is normally safe to say Y here.
See Documentation/nommu-mmap.txt for more information.
config [31mCONFIG_SYSTEM_DATA_VERIFICATION[0m
def_bool n
select [31mCONFIG_SYSTEM_TRUSTED_KEYRING[0m
select [31mCONFIG_KEYS[0m
select [31mCONFIG_CRYPTO[0m
select [31mCONFIG_CRYPTO_RSA[0m
select [31mCONFIG_ASYMMETRIC_KEY_TYPE[0m
select [31mCONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE[0m
select [31mCONFIG_ASN1[0m
select [31mCONFIG_OID_REGISTRY[0m
select [31mCONFIG_X509_CERTIFICATE_PARSER[0m
select [31mCONFIG_PKCS7_MESSAGE_PARSER[0m
help
Provide PKCS#7 message verification using the contents of the system
trusted keyring to provide public keys. This then can be used for
module verification, kexec image verification and firmware blob
verification.
config [31mCONFIG_PROFILING[0m
bool "Profiling support"
help
Say Y here to enable the extended profiling support mechanisms used
by profilers such as OProfile.
#
# Place an empty function call at each tracepoint site. Can be
# dynamically changed for a probe function.
#
config [31mCONFIG_TRACEPOINTS[0m
bool
source "arch/Kconfig"
endmenu # General setup
config [31mCONFIG_HAVE_GENERIC_DMA_COHERENT[0m
bool
default n
config [31mCONFIG_SLABINFO[0m
bool
depends on [31mCONFIG_PROC_FS[0m
depends on [31mCONFIG_SLAB[0m || [31mCONFIG_SLUB_DEBUG[0m
default y
config [31mCONFIG_RT_MUTEXES[0m
bool
config [31mCONFIG_BASE_SMALL[0m
int
default 0 if [31mCONFIG_BASE_FULL[0m
default 1 if ![31mCONFIG_BASE_FULL[0m
menuconfig [31mCONFIG_MODULES[0m
bool "Enable loadable module support"
option modules
help
Kernel modules are small pieces of compiled code which can
be inserted in the running kernel, rather than being
permanently built into the kernel. You use the "modprobe"
tool to add (and sometimes remove) them. If you say Y here,
many parts of the kernel can be built as modules (by
answering [31mCONFIG_M[0m instead of Y where indicated): this is most
useful for infrequently used options which are not required
for booting. For more information, see the man pages for
modprobe, lsmod, modinfo, insmod and rmmod.
If you say Y here, you will need to run "make
modules_install" to put the modules under /lib/modules/
where modprobe can find them (you may need to be root to do
this).
If unsure, say Y.
if [31mCONFIG_MODULES[0m
config [31mCONFIG_MODULE_FORCE_LOAD[0m
bool "Forced module loading"
default n
help
Allow loading of modules without version information (ie. modprobe
--force). Forced module loading sets the 'F' (forced) taint flag and
is usually a really bad idea.
config [31mCONFIG_MODULE_UNLOAD[0m
bool "Module unloading"
help
Without this option you will not be able to unload any
modules (note that some modules may not be unloadable
anyway), which makes your kernel smaller, faster
and simpler. If unsure, say Y.
config [31mCONFIG_MODULE_FORCE_UNLOAD[0m
bool "Forced module unloading"
depends on [31mCONFIG_MODULE_UNLOAD[0m
help
This option allows you to force a module to unload, even if the
kernel believes it is unsafe: the kernel will remove the module
without waiting for anyone to stop using it (using the -f option to
rmmod). This is mainly for kernel developers and desperate users.
If unsure, say N.
config [31mCONFIG_MODVERSIONS[0m
bool "Module versioning support"
help
Usually, you have to use modules compiled with your kernel.
Saying Y here makes it sometimes possible to use modules
compiled for different kernels, by adding enough information
to the modules to (hopefully) spot any changes which would
make them incompatible with the kernel you are running. If
unsure, say N.
config [31mCONFIG_MODULE_REL_CRCS[0m
bool
depends on [31mCONFIG_MODVERSIONS[0m
config [31mCONFIG_MODULE_SRCVERSION_ALL[0m
bool "Source checksum for all modules"
help
Modules which contain a MODULE_VERSION get an extra "srcversion"
field inserted into their modinfo section, which contains a
sum of the source files which made it. This helps maintainers
see exactly which source was used to build a module (since
others sometimes change the module source without updating
the version). With this option, such a "srcversion" field
will be created for all modules. If unsure, say N.
config [31mCONFIG_MODULE_SIG[0m
bool "Module signature verification"
depends on [31mCONFIG_MODULES[0m
select [31mCONFIG_SYSTEM_DATA_VERIFICATION[0m
help
Check modules for valid signatures upon load: the signature
is simply appended to the module. For more information see
Documentation/module-signing.txt.
Note that this option adds the OpenSSL development packages as a
kernel build dependency so that the signing tool can use its crypto
library.
!!!WARNING!!! If you enable this option, you MUST make sure that the
module DOES NOT get stripped after being signed. This includes the
debuginfo strip done by some packagers (such as rpmbuild) and
inclusion into an initramfs that wants the module size reduced.
config [31mCONFIG_MODULE_SIG_FORCE[0m
bool "Require modules to be validly signed"
depends on [31mCONFIG_MODULE_SIG[0m
help
Reject unsigned modules or signed modules for which we don't have a
key. Without this, such modules will simply taint the kernel.
config [31mCONFIG_MODULE_SIG_ALL[0m
bool "Automatically sign all modules"
default y
depends on [31mCONFIG_MODULE_SIG[0m
help
Sign all modules during make modules_install. Without this option,
modules must be signed manually, using the scripts/sign-file tool.
comment "Do not forget to sign required modules with scripts/sign-file"
depends on [31mCONFIG_MODULE_SIG_FORCE[0m && ![31mCONFIG_MODULE_SIG_ALL[0m
choice
prompt "Which hash algorithm should modules be signed with?"
depends on [31mCONFIG_MODULE_SIG[0m
help
This determines which sort of hashing algorithm will be used during
signature generation. This algorithm _must_ be built into the kernel
directly so that signature verification can take place. It is not
possible to load a signed module containing the algorithm to check
the signature on that module.
config [31mCONFIG_MODULE_SIG_SHA1[0m
bool "Sign modules with SHA-1"
select [31mCONFIG_CRYPTO_SHA1[0m
config [31mCONFIG_MODULE_SIG_SHA224[0m
bool "Sign modules with SHA-224"
select [31mCONFIG_CRYPTO_SHA256[0m
config [31mCONFIG_MODULE_SIG_SHA256[0m
bool "Sign modules with SHA-256"
select [31mCONFIG_CRYPTO_SHA256[0m
config [31mCONFIG_MODULE_SIG_SHA384[0m
bool "Sign modules with SHA-384"
select [31mCONFIG_CRYPTO_SHA512[0m
config [31mCONFIG_MODULE_SIG_SHA512[0m
bool "Sign modules with SHA-512"
select [31mCONFIG_CRYPTO_SHA512[0m
endchoice
config [31mCONFIG_MODULE_SIG_HASH[0m
string
depends on [31mCONFIG_MODULE_SIG[0m
default "sha1" if [31mCONFIG_MODULE_SIG_SHA1[0m
default "sha224" if [31mCONFIG_MODULE_SIG_SHA224[0m
default "sha256" if [31mCONFIG_MODULE_SIG_SHA256[0m
default "sha384" if [31mCONFIG_MODULE_SIG_SHA384[0m
default "sha512" if [31mCONFIG_MODULE_SIG_SHA512[0m
config [31mCONFIG_MODULE_COMPRESS[0m
bool "Compress modules on installation"
depends on [31mCONFIG_MODULES[0m
help
Compresses kernel modules when 'make modules_install' is run; gzip or
xz depending on "Compression algorithm" below.
module-init-tools MAY support gzip, and kmod MAY support gzip and xz.
Out-of-tree kernel modules installed using Kbuild will also be
compressed upon installation.
Note: for modules inside an initrd or initramfs, it's more efficient
to compress the whole initrd or initramfs instead.
Note: This is fully compatible with signed modules.
If in doubt, say N.
choice
prompt "Compression algorithm"
depends on [31mCONFIG_MODULE_COMPRESS[0m
default [31mCONFIG_MODULE_COMPRESS_GZIP[0m
help
This determines which sort of compression will be used during
'make modules_install'.
GZIP (default) and XZ are supported.
config [31mCONFIG_MODULE_COMPRESS_GZIP[0m
bool "GZIP"
config [31mCONFIG_MODULE_COMPRESS_XZ[0m
bool "XZ"
endchoice
config [31mCONFIG_TRIM_UNUSED_KSYMS[0m
bool "Trim unused exported kernel symbols"
depends on [31mCONFIG_MODULES[0m && ![31mCONFIG_UNUSED_SYMBOLS[0m
help
The kernel and some modules make many symbols available for
other modules to use via EXPORT_SYMBOL() and variants. Depending
on the set of modules being selected in your kernel configuration,
many of those exported symbols might never be used.
This option allows for unused exported symbols to be dropped from
the build. In turn, this provides the compiler more opportunities
(especially when using LTO) for optimizing the code and reducing
binary size. This might have some security advantages as well.
If unsure, or if you need to build out-of-tree modules, say N.
endif # [31mCONFIG_MODULES[0m
config [31mCONFIG_MODULES_TREE_LOOKUP[0m
def_bool y
depends on [31mCONFIG_PERF_EVENTS[0m || [31mCONFIG_TRACING[0m
config [31mCONFIG_INIT_ALL_POSSIBLE[0m
bool
help
Back when each arch used to define their own cpu_online_mask and
cpu_possible_mask, some of them chose to initialize cpu_possible_mask
with all 1s, and others with all 0s. When they were centralised,
it was better to provide this option than to break all the archs
and have several arch maintainers pursuing me down dark alleys.
source "block/Kconfig"
config [31mCONFIG_PREEMPT_NOTIFIERS[0m
bool
config [31mCONFIG_PADATA[0m
depends on [31mCONFIG_SMP[0m
bool
config [31mCONFIG_ASN1[0m
tristate
help
Build a simple ASN.1 grammar compiler that produces a bytecode output
that can be interpreted by the ASN.1 stream decoder and used to
inform it as to what tags are to be expected in a stream and what
functions to call on what tags.
source "kernel/Kconfig.locks"