mirror of
git://git.musl-libc.org/musl
synced 2024-12-12 18:01:27 +00:00
c8c3e341fb
"big-engian" should be "big-endian".
192 lines
6.6 KiB
Plaintext
192 lines
6.6 KiB
Plaintext
|
|
Quick Installation Guide for musl libc
|
|
======================================
|
|
|
|
There are many different ways to install musl depending on your usage
|
|
case. This document covers only the build and installation of musl by
|
|
itself, which is useful for upgrading an existing musl-based system or
|
|
compiler toolchain, or for using the provided musl-gcc wrapper with an
|
|
existing non-musl-based compiler.
|
|
|
|
Building complete native or cross-compiler toolchains is outside the
|
|
scope of this INSTALL file. More information can be found on the musl
|
|
website and community wiki.
|
|
|
|
|
|
Build Prerequisites
|
|
-------------------
|
|
|
|
The only build-time prerequisites for musl are GNU Make and a
|
|
freestanding C99 compiler toolchain targeting the desired instruction
|
|
set architecture and ABI, with support for a minimal subset of "GNU C"
|
|
extensions consisting mainly of gcc-style inline assembly, weak
|
|
aliases, hidden visibility, and stand-alone assembly source files.
|
|
|
|
GCC, LLVM/clang, Firm/cparser, and PCC have all successfully built
|
|
musl, but GCC is the most widely used/tested. Recent compiler (and
|
|
binutils) versions should be used if possible since some older
|
|
versions have bugs which affect musl.
|
|
|
|
The system used to build musl does not need to be Linux-based, nor do
|
|
the Linux kernel headers need to be available.
|
|
|
|
|
|
|
|
Supported Targets
|
|
-----------------
|
|
|
|
musl can be built for the following CPU instruction set architecture
|
|
and ABI combinations:
|
|
|
|
* i386
|
|
* Minimum CPU model is actually 80486 unless kernel emulation of
|
|
the `cmpxchg` instruction is added
|
|
|
|
* x86_64
|
|
* ILP32 ABI (x32) is available as a separate arch but is still
|
|
experimental
|
|
|
|
* ARM
|
|
* EABI, standard or hard-float VFP variant
|
|
* Little-endian default; big-endian variants also supported
|
|
* Compiler toolchains only support armv4t and later
|
|
|
|
* AArch64
|
|
* Little-endian default; big-endian variants also supported
|
|
|
|
* MIPS
|
|
* ABI is o32, fp32/fpxx (except on r6 which is fp64)
|
|
* Big-endian default; little-endian variants also supported
|
|
* Default ABI variant uses FPU registers; alternate soft-float ABI
|
|
that does not use FPU registers or instructions is available
|
|
* MIPS2 or later, or kernel emulation of ll/sc (standard in Linux)
|
|
is required
|
|
* MIPS32r6, an incompatible ISA, is supported as a variant "mipsr6"
|
|
|
|
* MIPS64
|
|
* ABI is n64 (LP64) or n32 (ILP32)
|
|
* Big-endian default; little-endian variants also supported
|
|
* Default ABI variant uses FPU registers; alternate soft-float ABI
|
|
that does not use FPU registers or instructions is available
|
|
|
|
* PowerPC
|
|
* Compiler toolchain must provide 64-bit long double, not IBM
|
|
double-double or IEEE quad
|
|
* For dynamic linking, compiler toolchain must be configured for
|
|
"secure PLT" variant
|
|
|
|
* PowerPC64
|
|
* Both little and big endian variants are supported
|
|
* Compiler toolchain must provide 64-bit long double, not IBM
|
|
double-double or IEEE quad
|
|
* Compiler toolchain must use the new (ELFv2) ABI regardless of
|
|
whether it is for little or big endian
|
|
|
|
* S390X (64-bit S390)
|
|
|
|
* SuperH (SH)
|
|
* Standard ELF ABI or FDPIC ABI (shared-text without MMU)
|
|
* Little-endian by default; big-endian variant also supported
|
|
* Full FPU ABI or soft-float ABI is supported, but the
|
|
single-precision-only FPU ABI is not
|
|
|
|
* Microblaze
|
|
* Big-endian default; little-endian variants also supported
|
|
* Soft-float
|
|
* Requires support for lwx/swx instructions
|
|
|
|
* OpenRISC 1000 (or1k)
|
|
|
|
* RISC-V 64
|
|
* Little endian
|
|
* Hard, soft, and hard-single/soft-double floating point ABIs
|
|
* Standard ELF; no shared-text NOMMU support
|
|
|
|
|
|
|
|
Build and Installation Procedure
|
|
--------------------------------
|
|
|
|
To build and install musl:
|
|
|
|
1. Run the provided configure script from the top-level source
|
|
directory, passing on its command line any desired options.
|
|
|
|
2. Run "make" to compile.
|
|
|
|
3. Run "make install" with appropriate privileges to write to the
|
|
target locations.
|
|
|
|
The configure script attempts to determine automatically the correct
|
|
target architecture based on the compiler being used. For some
|
|
compilers, this may not be possible. If detection fails or selects the
|
|
wrong architecture, you can provide an explicit selection on the
|
|
configure command line.
|
|
|
|
By default, configure installs to a prefix of "/usr/local/musl". This
|
|
differs from the behavior of most configure scripts, and is chosen
|
|
specifically to avoid clashing with libraries already present on the
|
|
system. DO NOT set the prefix to "/usr", "/usr/local", or "/" unless
|
|
you're upgrading libc on an existing musl-based system. Doing so will
|
|
break your existing system when you run "make install" and it may be
|
|
difficult to recover.
|
|
|
|
|
|
|
|
Notes on Dynamic Linking
|
|
------------------------
|
|
|
|
If dynamic linking is enabled, one file needs to be installed outside
|
|
of the installation prefix: /lib/ld-musl-$ARCH.so.1. This is the
|
|
dynamic linker. Its pathname is hard-coded into all dynamic-linked
|
|
programs, so for the sake of being able to share binaries between
|
|
systems, a consistent location should be used everywhere. Note that
|
|
the same applies to glibc and its dynamic linker, which is named
|
|
/lib/ld-linux.so.2 on i386 systems.
|
|
|
|
If for some reason it is impossible to install the dynamic linker in
|
|
its standard location (for example, if you are installing without root
|
|
privileges), the --syslibdir option to configure can be used to
|
|
provide a different location
|
|
|
|
At runtime, the dynamic linker needs to know the paths to search for
|
|
shared libraries. You should create a text file named
|
|
/etc/ld-musl-$ARCH.path (where $ARCH matches the architecture name
|
|
used in the dynamic linker) containing a list of directories where you
|
|
want the dynamic linker to search for shared libraries, separated by
|
|
colons or newlines. If the dynamic linker has been installed in a
|
|
non-default location, the path file also needs to reside at that
|
|
location (../etc relative to the chosen syslibdir).
|
|
|
|
If you do not intend to use dynamic linking, you may disable it by
|
|
passing --disable-shared to configure; this also cuts the build time
|
|
in half.
|
|
|
|
|
|
|
|
Checking for Successful Installation
|
|
------------------------------------
|
|
|
|
After installing, you should be able to use musl via the musl-gcc
|
|
wrapper. For example:
|
|
|
|
cat > hello.c <<EOF
|
|
#include <stdio.h>
|
|
int main()
|
|
{
|
|
printf("hello, world!\n");
|
|
return 0;
|
|
}
|
|
EOF
|
|
/usr/local/musl/bin/musl-gcc hello.c
|
|
./a.out
|
|
|
|
To configure autoconf-based program to compile and link against musl,
|
|
set the CC variable to musl-gcc when running configure, as in:
|
|
|
|
CC=musl-gcc ./configure ...
|
|
|
|
You will probably also want to use --prefix when building libraries to
|
|
ensure that they are installed under the musl prefix and not in the
|
|
main host system library directories.
|