NetBSD/sys/rump/README.compileopts

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$NetBSD: README.compileopts,v 1.17 2023/07/05 16:40:34 lukem Exp $
This file describes compile-time options for rump kernels.
Additionally, NetBSD build options will have an effect; see mk.conf(5)
and src/share/mk/bsd.README for a description of NetBSD build options.
Note: after changing an option, do a clean build.
Global options:
RUMP_DIAGNOSTIC
values: yes|no
defval: yes
effect: Iff "yes", build with -DDIAGNOSTIC.
RUMP_DEBUG
values: <defined> / <undefined>
defval: <undefined>
effect: Iff defined, build with -DDEBUG.
RUMP_LOCKDEBUG
values: <defined> / <undefined>
defval: <undefined>
effect: Iff defined, build with -DLOCKDEBUG.
RUMP_VNODE_LOCKDEBUG
values: <defined> / <undefined>
defval: <undefined>
effect: Iff defined, build with -DVNODE_LOCKDEBUG.
RUMP_KTRACE
values: yes|no
defval: yes
effect: Iff "yes", build with -DKTRACE.
RUMP_LOCKS_UP
values: yes|no
defval: no
effect: If "yes", build rump kernel with uniprocess-optimized locking.
An implication of this is that RUMP_NCPU==1 is required at
runtime. If "no", build with multiprocessor-capable locking.
RUMP_VIRTIF
values: yes|no
defval: yes
effect: Iff "yes", build the virt(4) network interface. Turning this
off may be necessary on systems that lack the necessary headers,
e.g. musl libc based Linux.
RUMP_CURLWP
values: hypercall/__thread/register or <undefined>
defval: <undefined>
effect: Control how curlwp is obtained in a rump kernel. This is
a very frequently accessed thread-local variable, and optimizing
access has a significant performance impact. Note that all
options are not available on hosts/machine architectures.
<undefined> - use default implementation (currently "hypercall")
hypercall - use a hypercall to fetch the value
__thread - use the __thread feature to fetch value via TLS
register - use a dedicated register (implies -ffixed)
RUMP_NBCOMPAT
values: comma-separated list of releases; e.g. "60,70";
or "all" or "default" or "none". Currently default == all (but
might not be so in the future)
defval: all
effect: Builds NetBSD COMPAT_nn code for each of the elements in the list.
This option is useful only when building rump kernels for
NetBSD userspace, and an empty value may be supplied elsewhere.
================================================================================
Per-component options:
RUMP_SYM_NORENAME
values: regexp matching symbol names
defval: <undefined>
effect: Causes matching symbols from the component to not be renamed
into the rump kernel symbol namespace (rumpns_). This option
can only be used in embedded environments where there is full
control over the platform's namespace. Conversely, this option
cannot be used in kernel components which are not meant to be
tied to a specific platform. Note: the value is processed by
make and must be appropriately escaped. example:
RUMP_SYM_NORENAME=HYPERVISOR_|block$$
will not rename "^HYPERVISOR_" or "^block$"
================================================================================
The rest of the options described in this file are not intended to be
set by users, but by the package building rump kernels.
RUMP_KERNEL_IS_LIBC
values: defined / not defined
effect: Iff defined, export normal system call symbols from libc.
For example, without this option rump_sys_open() is exported.
With this option, both open() and rump_sys_open() are exported.
This option is meant for building systems where a rump kernel
is the only operating system like component.
RUMP_LDSCRIPT
values: no/GNU/sun/ctor
defval: GNU
effect: Select the linker script to be used for linking rump kernel shared
library components.
no - do not use a linker script
GNU - use a linker script for GNU ld 2.18 and later
sun - use a linker script for the Solaris linker
ctor - do not use a linker script, make the code
generate __attribute__((constructor))