ucontext implementation featuring glibc-compatible ABI
A. Wilcox 6046eb47e4
Reorder registers in other x86_64 assembler files
2 years ago
arch Reorder registers in other x86_64 assembler files 2 years ago
.gitignore build: add libucontext test program 2 years ago
LICENSE don't bother with glibc stuff afterall, kernel defines ABI to use 2 years ago
Makefile build: use -lucontext instead of libucontext.so in linker flags for test program 2 years ago
README.md README: we support s390x now 2 years ago
test_libucontext.c test_libucontext: explain the stack poisoning part 2 years ago



libucontext is a library which provides the ucontext.h C API. Unlike other implementations, it faithfully follows the kernel process ABI when doing context swaps.

Notably, when combined with gcompat, it provides a fully compatible implementation of the ucontext functions that are ABI compatible with glibc.

supported architectures

Adding support for new architectures is easy, but you need to know assembly language to do it.

Right now these archs are supported and should work on bare metal:

  • x86
  • x86_64
  • armv6+ (arm)
  • aarch64
  • s390x

These archs require kernel assistance and use a syscall (the only assembly is the trampoline):

  • ppc
  • ppc64 (ELFv2 ABI spec only, ELFv1 not supported)


libucontext uses a simple makefile build system. You should define ARCH= at build time, otherwise the build system will attempt to guess using uname -m.

$ make ARCH=x86_64
$ make ARCH=x86_64 check
$ make ARCH=x86_64 DESTDIR=out install


libucontext is offered as part of the gcompat project. Accordingly, please address all questions and bug reports to gcompat@lists.adelielinux.org.