meson: support building docs

Toggleable with -Ddocs=(true|false), defaults to false.

Requires bumping minimum meson version to 0.59.0, or 0.61.0 to also
include symlinks.

.gitignore

@@ -1,5 +1,16 @@
+include/libucontext/bits.h
 *.o
+examples/cooperative_threading
 test_libucontext
+test_libucontext_posix
+test_libucontext_bare_posixabi
 libucontext.a
 libucontext.so
 libucontext.so.*
+libucontext_posix.a
+libucontext_posix.so
+libucontext_posix.so.*
+libucontext.pc
+*.tar.xz
+core
+*.core

.woodpecker.yml

@@ -0,0 +1,40 @@
+pipeline:
+  build-x86_64:
+    image: alpine
+    commands:
+      - apk add --no-cache build-base
+      - make check ARCH=x86_64
+    when:
+      platform: linux/amd64
+
+  build-s390x:
+    image: alpine
+    commands:
+      - apk add --no-cache build-base
+      - make check ARCH=s390x
+    when:
+      platform: linux/s390x
+
+  build-ppc64le:
+    image: alpine
+    commands:
+      - apk add --no-cache build-base
+      - make check ARCH=ppc64le
+    when:
+      platform: linux/ppc64le
+
+  build-armv7:
+    image: alpine
+    commands:
+      - apk add --no-cache build-base
+      - make check ARCH=arm
+    when:
+      platform: linux/arm
+
+  build-aarch64:
+    image: alpine
+    commands:
+      - apk add --no-cache build-base
+      - make check ARCH=aarch64
+    when:
+      platform: linux/arm64

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2018-2020 Ariadne Conill <ariadne@dereferenced.org>
+Copyright (c) 2018-2022 Ariadne Conill <ariadne@dereferenced.org>
 
 Permission to use, copy, modify, and/or distribute this software for any
 purpose with or without fee is hereby granted, provided that the above

Makefile

@@ -1,54 +1,284 @@
+SCDOC := scdoc
+
 ARCH := $(shell uname -m)
 ifeq ($(ARCH),$(filter $(ARCH),i386 i686))
 	override ARCH = x86
 endif
+ifeq ($(ARCH),$(filter $(ARCH),sh2 sh4))
+	override ARCH = sh
+endif
+ifeq ($(ARCH),$(filter $(ARCH),ppc64le))
+	override ARCH = ppc64
+endif
+ifeq ($(ARCH),$(filter $(ARCH),armv7l))
+	override ARCH = arm
+endif
+ifeq ($(ARCH),$(filter $(ARCH),arm64))
+	override ARCH = aarch64
+endif
 
-LIBDIR := /lib
-CFLAGS := -ggdb3 -O2 -Wall
-CPPFLAGS := -Iarch/${ARCH} -Iarch/common
+prefix = /usr
+libdir = ${prefix}/lib
+shared_libdir = ${libdir}
+static_libdir = ${libdir}
+includedir = ${prefix}/include
+pkgconfigdir = ${prefix}/lib/pkgconfig
+
+CFLAGS ?= -ggdb3 -O2 -Wall
+CPPFLAGS := -Iinclude -Iarch/${ARCH} -Iarch/common
+ifneq ($(shell uname),Darwin)
+	EXPORT_UNPREFIXED := yes
+else
+	# Darwin does not support aliases
+	EXPORT_UNPREFIXED := no
+endif
+FREESTANDING := no
+
+ifeq ($(FREESTANDING),yes)
+	CPPFLAGS += -DFREESTANDING
+	EXPORT_UNPREFIXED = no
+endif
+
+FORCE_SOFT_FLOAT := no
+
+ifeq ($(FORCE_SOFT_FLOAT),yes)
+        CPPFLAGS += -DFORCE_SOFT_FLOAT
+endif
+
+FORCE_HARD_FLOAT := no
+
+ifeq ($(FORCE_HARD_FLOAT),yes)
+        CPPFLAGS += -DFORCE_HARD_FLOAT
+endif
+
+ifeq ($(EXPORT_UNPREFIXED),yes)
+	CPPFLAGS += -DEXPORT_UNPREFIXED
+endif
 
 LIBUCONTEXT_C_SRC = $(wildcard arch/${ARCH}/*.c)
 LIBUCONTEXT_S_SRC = $(wildcard arch/${ARCH}/*.S)
 
+ifeq ($(shell test -d arch/${ARCH}/include; echo $?),0)
+	CPPFLAGS += -Iarch/${ARCH}/include
+endif
+
+LIBUCONTEXT_VERSION := $(shell head -n 1 VERSION)
 LIBUCONTEXT_OBJ = ${LIBUCONTEXT_C_SRC:.c=.o} ${LIBUCONTEXT_S_SRC:.S=.o}
-LIBUCONTEXT_SOVERSION = 0
-LIBUCONTEXT_NAME = libucontext.so
+LIBUCONTEXT_SOVERSION = 1
+ifeq ($(shell uname),Darwin)
+	LIBUCONTEXT_NAME = libucontext.dylib
+	LIBUCONTEXT_SONAME = libucontext.${LIBUCONTEXT_SOVERSION}.dylib
+	LIBUCONTEXT_POSIX_NAME = libucontext_posix.dylib
+	LIBUCONTEXT_POSIX_SONAME = libucontext_posix.${LIBUCONTEXT_SOVERSION}.dylib
+	LIBUCONTEXT_LINKER_FLAGS = -Wl,-dynamiclib,-install_name,${LIBUCONTEXT_SONAME},-current_version,${LIBUCONTEXT_SOVERSION},-compatibility_version,${LIBUCONTEXT_SOVERSION}
+	LIBUCONTEXT_POSIX_LINKER_FLAGS = -Wl,-dynamiclib,-install_name,${LIBUCONTEXT_POSIX_SONAME},-current_version,${LIBUCONTEXT_SOVERSION},-compatibility_version,${LIBUCONTEXT_SOVERSION}
+else
+	LIBUCONTEXT_NAME = libucontext.so
+	LIBUCONTEXT_SONAME = libucontext.so.${LIBUCONTEXT_SOVERSION}
+	LIBUCONTEXT_POSIX_NAME = libucontext_posix.so
+	LIBUCONTEXT_POSIX_SONAME = libucontext_posix.so.${LIBUCONTEXT_SOVERSION}
+	LIBUCONTEXT_LINKER_FLAGS = -shared -Wl,-soname,${LIBUCONTEXT_SONAME} -Wl,-z,noexecstack
+	LIBUCONTEXT_POSIX_LINKER_FLAGS = -shared -Wl,-soname,${LIBUCONTEXT_POSIX_SONAME} -Wl,-z,noexecstack
+	ASFLAGS = -Wa,--noexecstack
+endif
 LIBUCONTEXT_STATIC_NAME = libucontext.a
-LIBUCONTEXT_SONAME = libucontext.so.${LIBUCONTEXT_SOVERSION}
-LIBUCONTEXT_PATH = ${LIBDIR}/${LIBUCONTEXT_SONAME}
-LIBUCONTEXT_STATIC_PATH = ${LIBDIR}/${LIBUCONTEXT_STATIC_NAME}
+LIBUCONTEXT_PC = libucontext.pc
+LIBUCONTEXT_PATH = ${shared_libdir}/${LIBUCONTEXT_SONAME}
+LIBUCONTEXT_STATIC_PATH = ${static_libdir}/${LIBUCONTEXT_STATIC_NAME}
+LIBUCONTEXT_HEADERS = \
+	include/libucontext/libucontext.h \
+	include/libucontext/bits.h
+LIBUCONTEXT_EXAMPLES = \
+	examples/cooperative_threading
+LIBUCONTEXT_POSIX_STATIC_NAME = libucontext_posix.a
+LIBUCONTEXT_POSIX_C_SRC = libucontext_posix.c
+LIBUCONTEXT_POSIX_OBJ = ${LIBUCONTEXT_POSIX_C_SRC:.c=.o}
+LIBUCONTEXT_POSIX_PATH = ${shared_libdir}/${LIBUCONTEXT_POSIX_SONAME}
+LIBUCONTEXT_POSIX_STATIC_PATH = ${static_libdir}/${LIBUCONTEXT_POSIX_STATIC_NAME}
 
-all: ${LIBUCONTEXT_SONAME} ${LIBUCONTEXT_STATIC_NAME}
+ifeq ($(FREESTANDING),yes)
+	LIBUCONTEXT_POSIX_NAME =
+	LIBUCONTEXT_POSIX_STATIC_NAME =
+endif
 
-${LIBUCONTEXT_STATIC_NAME}: ${LIBUCONTEXT_OBJ}
+all: ${LIBUCONTEXT_SONAME} ${LIBUCONTEXT_STATIC_NAME} ${LIBUCONTEXT_POSIX_NAME} ${LIBUCONTEXT_POSIX_STATIC_NAME} ${LIBUCONTEXT_PC}
+
+${LIBUCONTEXT_POSIX_NAME}: ${LIBUCONTEXT_NAME} ${LIBUCONTEXT_POSIX_OBJ}
+	$(CC) -fPIC -o ${LIBUCONTEXT_POSIX_NAME} ${LIBUCONTEXT_POSIX_LINKER_FLAGS} ${LIBUCONTEXT_POSIX_OBJ} -L. -lucontext ${LDFLAGS}
+
+${LIBUCONTEXT_POSIX_STATIC_NAME}: ${LIBUCONTEXT_STATIC_NAME} ${LIBUCONTEXT_POSIX_OBJ}
+	$(AR) rcs ${LIBUCONTEXT_POSIX_STATIC_NAME} ${LIBUCONTEXT_POSIX_OBJ}
+
+${LIBUCONTEXT_POSIX_SONAME}: ${LIBUCONTEXT_POSIX_NAME}
+	ln -sf ${LIBUCONTEXT_POSIX_NAME} ${LIBUCONTEXT_POSIX_SONAME}
+
+${LIBUCONTEXT_STATIC_NAME}: ${LIBUCONTEXT_HEADERS} ${LIBUCONTEXT_OBJ}
 	$(AR) rcs ${LIBUCONTEXT_STATIC_NAME} ${LIBUCONTEXT_OBJ}
 
-${LIBUCONTEXT_NAME}: ${LIBUCONTEXT_OBJ}
-	$(CC) -o ${LIBUCONTEXT_NAME} -Wl,-soname,${LIBUCONTEXT_SONAME} \
-		-shared ${LIBUCONTEXT_OBJ} ${LDFLAGS}
+${LIBUCONTEXT_NAME}: ${LIBUCONTEXT_HEADERS} ${LIBUCONTEXT_OBJ}
+	$(CC) -fPIC -o ${LIBUCONTEXT_NAME} ${LIBUCONTEXT_LINKER_FLAGS} ${LIBUCONTEXT_OBJ} ${LDFLAGS}
 
 ${LIBUCONTEXT_SONAME}: ${LIBUCONTEXT_NAME}
 	ln -sf ${LIBUCONTEXT_NAME} ${LIBUCONTEXT_SONAME}
 
+${LIBUCONTEXT_PC}: libucontext.pc.in
+	sed -e s:@LIBUCONTEXT_VERSION@:${LIBUCONTEXT_VERSION}:g \
+	    -e s:@LIBUCONTEXT_SHARED_LIBDIR@:${shared_libdir}:g \
+	    -e s:@LIBUCONTEXT_STATIC_LIBDIR@:${static_libdir}:g \
+	    -e s:@LIBUCONTEXT_INCLUDEDIR@:${includedir}:g $< > $@
+
+MANPAGES_SYMLINKS_3 = \
+	libucontext_getcontext.3 \
+	libucontext_makecontext.3 \
+	libucontext_setcontext.3 \
+	libucontext_swapcontext.3
+MANPAGES_3 = doc/libucontext.3
+
+MANPAGES = ${MANPAGES_3}
+
+.scd.3:
+	${SCDOC} < $< > $@
+
+.SUFFIXES: .scd .3
+
+docs: ${MANPAGES}
+
 .c.o:
-	$(CC) -std=c99 -D_BSD_SOURCE -fPIC -DPIC ${CFLAGS} ${CPPFLAGS} -c -o $@ $<
+	$(CC) -std=gnu99 -D_BSD_SOURCE -fPIC -DPIC ${CFLAGS} ${CPPFLAGS} -c -o $@ $<
 
 .S.o:
-	$(CC) -fPIC -DPIC ${CFLAGS} ${CPPFLAGS} -c -o $@ $<
+	$(CC) -fPIC -DPIC ${CFLAGS} ${CPPFLAGS} ${ASFLAGS} -c -o $@ $<
 
-clean:
-	rm -f ${LIBUCONTEXT_NAME} ${LIBUCONTEXT_SONAME} ${LIBUCONTEXT_STATIC_NAME} \
-		${LIBUCONTEXT_OBJ} test_libucontext
+${LIBUCONTEXT_NAME}_clean:
+	rm -f ${LIBUCONTEXT_NAME}
+
+${LIBUCONTEXT_SONAME}_clean:
+	rm -f ${LIBUCONTEXT_SONAME}
+
+${LIBUCONTEXT_STATIC_NAME}_clean:
+	rm -f ${LIBUCONTEXT_STATIC_NAME}
+
+libucontext_obj_clean:
+	rm -f ${LIBUCONTEXT_OBJ}
+
+${LIBUCONTEXT_PC}_clean:
+	rm -f ${LIBUCONTEXT_PC}
+
+bits_clean:
+	rm -f include/libucontext/bits.h
+
+${LIBUCONTEXT_POSIX_NAME}_clean:
+	rm -f ${LIBUCONTEXT_POSIX_NAME}
+
+${LIBUCONTEXT_POSIX_SONAME}_clean:
+	rm -f ${LIBUCONTEXT_POSIX_SONAME}
+
+${LIBUCONTEXT_POSIX_STATIC_NAME}_clean:
+	rm -f ${LIBUCONTEXT_POSIX_STATIC_NAME}
+
+libucontext_posix_obj_clean:
+	rm -f ${LIBUCONTEXT_POSIX_OBJ}
+
+check_clean: check_bare_clean check_posix_clean check_bare_posixabi_clean
+
+check_bare_clean:
+	rm -f test_libucontext
+
+check_posix_clean:
+	rm -f test_libucontext_posix
+
+check_bare_posixabi_clean:
+	rm -f test_libucontext_bare_posixabi
+
+docs_clean:
+	rm -f ${MANPAGES}
+
+clean: ${LIBUCONTEXT_NAME}_clean
+clean: ${LIBUCONTEXT_SONAME}_clean
+clean: ${LIBUCONTEXT_STATIC_NAME}_clean
+clean: ${LIBUCONTEXT_PC}_clean
+clean: bits_clean
+clean: ${LIBUCONTEXT_POSIX_NAME}_clean
+clean: ${LIBUCONTEXT_POSIX_SONAME}_clean
+clean: ${LIBUCONTEXT_POSIX_STATIC_NAME}_clean
+clean: libucontext_posix_obj_clean
+clean: libucontext_obj_clean
+clean: check_clean
+clean: docs_clean
 
 install: all
 	install -D -m755 ${LIBUCONTEXT_NAME} ${DESTDIR}${LIBUCONTEXT_PATH}
 	install -D -m664 ${LIBUCONTEXT_STATIC_NAME} ${DESTDIR}${LIBUCONTEXT_STATIC_PATH}
-	ln -sf ${LIBUCONTEXT_SONAME} ${DESTDIR}${LIBDIR}/${LIBUCONTEXT_NAME}
+	ln -sf ${LIBUCONTEXT_SONAME} ${DESTDIR}${shared_libdir}/${LIBUCONTEXT_NAME}
+	for i in ${LIBUCONTEXT_HEADERS}; do \
+		destfn=$$(echo $$i | sed s:include/::g); \
+		install -D -m644 $$i ${DESTDIR}${includedir}/$$destfn; \
+	done
+	install -D -m644 ${LIBUCONTEXT_PC} ${DESTDIR}${pkgconfigdir}/${LIBUCONTEXT_PC}
+	if [ -n "${LIBUCONTEXT_POSIX_NAME}" ]; then \
+		install -D -m755 ${LIBUCONTEXT_POSIX_NAME} ${DESTDIR}${LIBUCONTEXT_POSIX_PATH}; \
+		install -D -m644 ${LIBUCONTEXT_POSIX_STATIC_NAME} ${DESTDIR}${LIBUCONTEXT_POSIX_STATIC_PATH}; \
+	fi
 
-check: test_libucontext ${LIBUCONTEXT_SONAME}
+install_docs: docs
+	install -D -m644 doc/libucontext.3 ${DESTDIR}/usr/share/man/man3/libucontext.3
+	for i in ${MANPAGES_SYMLINKS_3}; do \
+		ln -s libucontext.3 ${DESTDIR}/usr/share/man/man3/$$i; \
+	done
+
+ifneq (${FREESTANDING},yes)
+check: check_libucontext_posix
+
+check_libucontext_posix: test_libucontext_posix ${LIBUCONTEXT_POSIX_SONAME} ${LIBUCONTEXT_SONAME}
+	env LD_LIBRARY_PATH=$(shell pwd) ./test_libucontext_posix
+
+test_libucontext_posix: test_libucontext_posix.c ${LIBUCONTEXT_POSIX_NAME}
+	$(CC) -std=gnu99 -D_BSD_SOURCE ${CFLAGS} ${CPPFLAGS} $@.c -o $@ -L. -lucontext -lucontext_posix
+endif
+
+ifeq ($(EXPORT_UNPREFIXED),yes)
+check: check_libucontext_bare_posixabi
+
+check_libucontext_bare_posixabi: test_libucontext_bare_posixabi ${LIBUCONTEXT_SONAME}
+	env LD_LIBRARY_PATH=$(shell pwd) ./test_libucontext_bare_posixabi
+
+test_libucontext_bare_posixabi: test_libucontext_posix.c ${LIBUCONTEXT_NAME}
+	$(CC) -std=gnu99 -D_BSD_SOURCE ${CFLAGS} ${CPPFLAGS} test_libucontext_posix.c -o $@ -L. -lucontext
+endif
+
+check_libucontext: test_libucontext ${LIBUCONTEXT_SONAME}
 	env LD_LIBRARY_PATH=$(shell pwd) ./test_libucontext
 
-test_libucontext: test_libucontext.c ${LIBUCONTEXT_NAME}
-	$(CC) -std=c99 -D_BSD_SOURCE ${CFLAGS} ${CPPFLAGS} $@.c -o $@ -L. -lucontext
+check: check_libucontext
 
-.PHONY: check
+test_libucontext: test_libucontext.c ${LIBUCONTEXT_NAME}
+	$(CC) -std=gnu99 -D_BSD_SOURCE ${CFLAGS} ${CPPFLAGS} $@.c -o $@ -L. -lucontext
+
+examples: ${LIBUCONTEXT_EXAMPLES}
+examples/cooperative_threading: examples/cooperative_threading.c ${LIBUCONTEXT_NAME}
+	$(CC) -std=gnu99 -D_BSD_SOURCE ${CFLAGS} ${CPPFLAGS} $@.c -o $@ -L. -lucontext
+
+ifeq ($(FREESTANDING),no)
+
+include/libucontext/bits.h: arch/common/include/libucontext/bits.h
+	cp $< $@
+
+else
+
+include/libucontext/bits.h: arch/${ARCH}/include/libucontext/bits.h
+	cp $< $@
+
+endif
+
+PACKAGE_NAME = libucontext
+PACKAGE_VERSION = ${LIBUCONTEXT_VERSION}
+DIST_NAME = ${PACKAGE_NAME}-${PACKAGE_VERSION}
+DIST_TARBALL = ${DIST_NAME}.tar.xz
+
+distcheck: check dist
+dist: ${DIST_TARBALL}
+${DIST_TARBALL}:
+	git archive --format=tar --prefix=${DIST_NAME}/ -o ${DIST_NAME}.tar ${DIST_NAME}
+	xz ${DIST_NAME}.tar
+
+.PHONY: check dist

NEWS

@@ -1,3 +1,77 @@
+Changes from 1.1 to 1.2
+-----------------------
+
+* Added Loongarch64 port.
+
+* Added OpenRISC (or1k) port.
+
+* Fixed various build system issues:
+  - libucontext_posix.so is no longer underlinked
+  - Executable stacks are now disabled when using GNU-like toolchains
+  - CPPFLAGS is used consistently
+  - Users may now build on Darwin without using Meson
+
+* aarch64 now implements the necessary SIMD register save/restore as
+  mandatory in AAPCS64.
+  Patches contributed by Richard Campbell.
+
+Changes from 1.0 to 1.1
+-----------------------
+
+* Added RISC-V RV32 port.
+
+* Cleaned up use of _GNU_SOURCE in C code.
+  Partially from patches contributed by osy.
+
+* Added automatic detection of armv7l architecture.
+  Patch contributed by Leandro Pereira.
+
+* Fixed installation path of libucontext_posix.a.
+
+* Work around deficiency in clang built-in assembler on AArch64 targets.
+  Patch contributed by osy.
+
+Changes from 0.13.1 to 1.0
+--------------------------
+
+* Implement common libucontext_trampoline, written in C with inline
+  assembly.
+
+* Added Renesas / Hitachi SH-2/SH-4 port (sh).
+
+* Added Meson build system, primarily for the convenience of using
+  libucontext with qemu as a subproject.
+
+* Added support for Mach-O ABI.
+
+* Fixed deficiencies in libucontext ABI, SONAME has been bumped due
+  to the ABI regressions in 0.13.
+
+Changes from 0.13 to 0.13.1
+---------------------------
+
+* Fix installation of libucontext.pc.
+  Patch contributed by Ömer Faruk IRMAK.
+
+Changes from 0.12 to 0.13
+-------------------------
+
+* Aligned RISC-V RV64 port's header usage with musl 1.2 to remove
+  warnings and ensure consistent register name usage.
+
+* Added Motorola 680X0 / NXP ColdFire port (m68k).
+
+* Added support for building for bare-metal targets with newlib via
+  make FREESTANDING=yes.  Other OS are also supported (for example,
+  the m68k freestanding port was tested on AmigaOS), PowerPC requires
+  kernel assistance and cannot be built with FREESTANDING=yes.  Not
+  all ports have support for FREESTANDING yet, patches welcome.
+
+Changes from 0.11 to 0.12
+-------------------------
+
+* Fixed compilation of RISC-V RV64 port with modern musl releases.
+
 Changes from 0.10 to 0.11
 -------------------------
 

README.md

@@ -6,26 +6,33 @@ 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.
 
+Since version 0.13, for some architectures, you can deploy to bare metal using newlib via the
+`FREESTANDING=yes` make option.  Systems which use a syscall cannot work this way.  The table
+below shows which architecture ports have been adapted to build with `FREESTANDING=yes`.
 
-## supported architectures
+Adding support for new architectures is easy, but you need to know assembly language for the
+target to do it.
 
-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:
+## supported features
 
- * x86
- * x86_64
- * armv6+ (`arm`)
- * aarch64
- * s390x
- * mips (O32 ABI only)
- * mips64 (N32/N64 ABI only, like Alpine, only N64 ABI has been tested)
- * riscv64
-
-These archs require kernel assistance and use a syscall:
-
- * ppc
- * ppc64 (ELFv2 ABI spec only, ELFv1 not supported)
+| Architecture | Works on musl | Syscall | Supports FREESTANDING | Common trampoline |
+|--------------|---------------|---------|-----------------------|-------------------|
+|    aarch64   | ✓             |         | ✓                     | ✓                 |
+|      arm     | ✓             |         | ✓                     | ✓                 |
+| loongarch64  | ✓             |         | ✓                     |                   |
+|     m68k     | ✓             |         | ✓                     | ✓                 |
+|     mips     | ✓             |         | ✓                     |                   |
+|    mips64    | ✓             |         | ✓                     |                   |
+|     or1k     | ✓             |         | ✓                     | ✓                 |
+|      ppc     | ✓             | ✓       |                       |                   |
+|     ppc64    | ✓             | ✓       |                       |                   |
+|    riscv32   | ✓             |         | ✓                     | ✓                 |
+|    riscv64   | ✓             |         | ✓                     | ✓                 |
+|     s390x    | ✓             |         | ✓                     |                   |
+|      sh      | ✓             |         | ✓                     | ✓                 |
+|      x86     | ✓             |         | ✓                     | ✓                 |
+|    x86_64    | ✓             |         | ✓                     | ✓                 |
 
 
 ## building
@@ -38,3 +45,61 @@ $ make ARCH=x86_64
 $ make ARCH=x86_64 check
 $ make ARCH=x86_64 DESTDIR=out install
 ```
+
+There are a few options:
+
+* `ARCH`: The architecture libucontext is being built for.  Must be set to one of the architectures
+  listed in the feature support table.  If unset, the build system will attempt to guess based on what
+  architecture the host is running.  Setting this option explicitly is highly recommended.
+
+* `FREESTANDING`: If this is set to `yes`, the system ucontext.h headers will not be used.  Instead,
+  the headers in `arch/${ARCH}/freestanding` will be used for definitions where appropriate.
+  Default is `no`.
+
+* `EXPORT_UNPREFIXED`: If this is set to `yes`, the POSIX 2004 names `getcontext`, `setcontext`,
+  `swapcontext` and `makecontext` will be provided as weak symbols aliased against their `libucontext_`
+  namespaced equivalents.  This is necessary for libucontext to provide these functions on musl
+  systems, but you may wish to disable this when using `FREESTANDING` mode to avoid conflicts with
+  the target's libc.  Default is `yes`.
+
+* `DESTDIR`: If this variable is set, the installed files will be installed to the specified path instead
+  of the system root.
+
+If you have `scdoc` installed, you can build manpages and install them:
+
+```
+$ make docs
+$ make DESTDIR=out install_docs
+```
+
+
+## real-world use cases
+
+`libucontext` is used on almost all musl distributions to provide the legacy `ucontext.h` API.
+Additionally, it is used by:
+
+* [UTM](https://getutm.app) -- friendly qemu distribution for macOS and iOS devices.  UTM uses libucontext
+  as qemu's coroutine backend.
+
+* [Lwan](https://lwan.ws) -- a high-performance embeddable asynchronous web server.  Lwan uses libucontext
+  to provide green threads when building on non-x86 architectures.
+
+
+## caveats
+
+`libucontext`, while largely functionally equivalent does have some differences over traditional POSIX
+ucontext functions:
+
+* Saving and restoring the signal mask is not implemented by default in order to avoid kernel syscall
+  overhead.  Use `-lucontext_posix` if you actually need this functionality, which provides a POSIX
+  compliant implementation at the cost of performance.
+
+* Only basic GPR registers are saved and restored when context swapping.  The glibc implementation uses
+  hardware capability detection to save/restore other register groups, such as the FPU registers or
+  vector processing (AltiVec/AVX/NEON) registers.  Adding this capability detection would significantly
+  increase the complexity of the project and thus is not implemented.  Support for compiling in code to
+  save/restore FPU registers or vector registers may be added in a later release as a build-time
+  setting -- for now, we assume a soft-float ABI with no optional processor features.  In practice, this
+  does not really matter, code using these functions are unlikely to be impacted by this design
+  assumption. This is a work in progress, as newer compilers will spill even non-floating-point state
+  through floating point registers when allowed to do so.

VERSION

@@ -0,0 +1 @@
+1.2

arch/aarch64/defs.h

@@ -9,6 +9,7 @@
 #define SP_OFFSET	432
 #define PC_OFFSET	440
 #define PSTATE_OFFSET	448
+#define FPSIMD_CONTEXT_OFFSET 464
 
 #ifndef FPSIMD_MAGIC
 # define FPSIMD_MAGIC	0x46508001
@@ -18,6 +19,9 @@
 # define ESR_MAGIC	0x45535201
 #endif
 
+#define FETCH_LINKPTR(dest) \
+	asm("mov	%0, x19" : "=r" ((dest)))
+
 #include "common-defs.h"
 
 #endif

arch/aarch64/getcontext.S

@@ -12,9 +12,14 @@
 
 #include "defs.h"
 
-ALIAS(getcontext, __getcontext)
+ALIAS(getcontext, libucontext_getcontext)
+ALIAS(__getcontext, libucontext_getcontext)
 
-FUNC(__getcontext)
+	.global PROC_NAME(libucontext_getcontext);
+	.align  2;
+	TYPE(libucontext_getcontext)
+	ENT(libucontext_getcontext)
+PROC_NAME(libucontext_getcontext):
 	str	xzr, [x0, #REG_OFFSET(0)]
 
 	/* save GPRs */
@@ -45,8 +50,12 @@ FUNC(__getcontext)
 	/* save pstate */
 	str	xzr, [x0, #PSTATE_OFFSET]
 
-	/* TODO: SIMD / FPRs */
+	add x2, x0, #FPSIMD_CONTEXT_OFFSET
+	stp q8, q9,   [x2, #144]
+	stp q10, q11, [x2, #176]
+	stp q12, q13, [x2, #208]
+	stp q14, q15, [x2, #240]
 
 	mov	x0, #0
 	ret
-END(__getcontext)
+END(libucontext_getcontext)

arch/aarch64/include/libucontext/bits.h

@@ -0,0 +1,34 @@
+#ifndef LIBUCONTEXT_BITS_H
+#define LIBUCONTEXT_BITS_H
+
+typedef unsigned long libucontext_greg_t;
+typedef unsigned long libucontext_gregset_t[34];
+
+typedef struct {
+	__uint128_t vregs[32];
+	unsigned int fpsr;
+	unsigned int fpcr;
+} libucontext_fpregset_t;
+
+typedef struct sigcontext {
+	unsigned long fault_address;
+	unsigned long regs[31];
+	unsigned long sp, pc, pstate;
+	long double __reserved[256];
+} libucontext_mcontext_t;
+
+typedef struct {
+	void *ss_sp;
+	int ss_flags;
+	size_t ss_size;
+} libucontext_stack_t;
+
+typedef struct libucontext_ucontext {
+	unsigned long uc_flags;
+	struct libucontext_ucontext *uc_link;
+	libucontext_stack_t uc_stack;
+	unsigned char __pad[136];
+	libucontext_mcontext_t uc_mcontext;
+} libucontext_ucontext_t;
+
+#endif

arch/aarch64/makecontext.c

@@ -10,21 +10,24 @@
  * from the use of this software.
  */
 
-#define _GNU_SOURCE
 #include <stddef.h>
 #include <stdarg.h>
-#include <signal.h>
 #include <string.h>
 #include <stdint.h>
 #include <stdio.h>
 #include "defs.h"
+#include <libucontext/libucontext.h>
 
 
-extern void __start_context(void);
+extern void libucontext_trampoline(void);
 
+_Static_assert(offsetof(libucontext_ucontext_t, uc_mcontext.regs[0]) == R0_OFFSET, "R0_OFFSET is invalid");
+_Static_assert(offsetof(libucontext_ucontext_t, uc_mcontext.sp) == SP_OFFSET, "SP_OFFSET is invalid");
+_Static_assert(offsetof(libucontext_ucontext_t, uc_mcontext.pc) == PC_OFFSET, "PC_OFFSET is invalid");
+_Static_assert(offsetof(libucontext_ucontext_t, uc_mcontext.pstate) == PSTATE_OFFSET, "PSTATE_OFFSET is invalid");
 
 void
-__makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
+libucontext_makecontext(libucontext_ucontext_t *ucp, void (*func)(void), int argc, ...)
 {
 	unsigned long *sp;
 	unsigned long *regp;
@@ -38,7 +41,7 @@ __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
 	ucp->uc_mcontext.sp = (uintptr_t) sp;
 	ucp->uc_mcontext.pc = (uintptr_t) func;
 	ucp->uc_mcontext.regs[19] = (uintptr_t) ucp->uc_link;
-	ucp->uc_mcontext.regs[30] = (uintptr_t) &__start_context;
+	ucp->uc_mcontext.regs[30] = (uintptr_t) &libucontext_trampoline;
 
 	va_start(va, argc);
 
@@ -53,5 +56,7 @@ __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
 	va_end(va);
 }
 
-
-extern __typeof(__makecontext) makecontext __attribute__((weak, __alias__("__makecontext")));
+#ifdef EXPORT_UNPREFIXED
+extern __typeof(libucontext_makecontext) makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+extern __typeof(libucontext_makecontext) __makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+#endif

arch/aarch64/setcontext.S

@@ -12,9 +12,14 @@
 
 #include "defs.h"
 
-ALIAS(setcontext, __setcontext)
+ALIAS(setcontext, libucontext_setcontext)
+ALIAS(__setcontext, libucontext_setcontext)
 
-FUNC(__setcontext)
+	.global PROC_NAME(libucontext_setcontext);
+	.align  2;
+	TYPE(libucontext_setcontext)
+	ENT(libucontext_setcontext)
+PROC_NAME(libucontext_setcontext):
 	/* restore GPRs */
 	ldp	x18, x19, [x0, #REG_OFFSET(18)]
 	ldp	x20, x21, [x0, #REG_OFFSET(20)]
@@ -28,7 +33,11 @@ FUNC(__setcontext)
 	ldr	x2, [x0, #SP_OFFSET]
 	mov	sp, x2
 
-	/* TODO: SIMD / FPRs */
+	add x2, x0, #FPSIMD_CONTEXT_OFFSET
+	ldp q8, q9,   [x2, #144]
+	ldp q10, q11, [x2, #176]
+	ldp q12, q13, [x2, #208]
+	ldp q14, q15, [x2, #240]
 
 	/* save current program counter in link register */
 	ldr	x16, [x0, #PC_OFFSET]
@@ -41,4 +50,4 @@ FUNC(__setcontext)
 
 	/* jump to new PC */
 	br	x16
-END(__setcontext)
+END(libucontext_setcontext)

arch/aarch64/swapcontext.S

@@ -12,9 +12,14 @@
 
 #include "defs.h"
 
-ALIAS(swapcontext, __swapcontext)
+ALIAS(swapcontext, libucontext_swapcontext)
+ALIAS(__swapcontext, libucontext_swapcontext)
 
-FUNC(__swapcontext)
+	.global PROC_NAME(libucontext_swapcontext);
+	.align  2;
+	TYPE(libucontext_swapcontext)
+	ENT(libucontext_swapcontext)
+PROC_NAME(libucontext_swapcontext):
 	str	xzr, [x0, #REG_OFFSET(0)]
 
 	/* save GPRs */
@@ -44,15 +49,21 @@ FUNC(__swapcontext)
 	/* save pstate */
 	str	xzr, [x0, #PSTATE_OFFSET]
 
+	add x2, x0, #FPSIMD_CONTEXT_OFFSET
+	stp q8, q9,   [x2, #144]
+	stp q10, q11, [x2, #176]
+	stp q12, q13, [x2, #208]
+	stp q14, q15, [x2, #240]
+
 	/* context to swap to is in x1 so... we move to x0 and call setcontext */
 	/* store our link register in x28 */
 	mov	x28, x30
 
 	/* move x1 to x0 and call setcontext */
 	mov	x0, x1
-	bl	__setcontext
+	bl	PROC_NAME(libucontext_setcontext)
 
 	/* hmm, we came back here try to return */
 	mov	x30, x28
 	ret
-END(__swapcontext)
+END(libucontext_swapcontext)

arch/aarch64/trampoline.c

@@ -0,0 +1,3 @@
+#include "defs.h"
+#include <libucontext/libucontext.h>
+#include "common-trampoline.c"

arch/arm/defs.h

@@ -2,8 +2,13 @@
 
 #define REG_SZ		(4)
 #define MCONTEXT_GREGS	(32)
+#define VFP_MAGIC_OFFSET (232)
+#define VFP_D8_OFFSET (304)
 
-#define TYPE(__proc)
+#define TYPE(__proc)	.type	__proc, %function;
+
+#define FETCH_LINKPTR(dest) \
+	asm("movs    %0, r4" : "=r" ((dest)))
 
 #include "common-defs.h"
 

arch/arm/getcontext.S

@@ -12,16 +12,38 @@
 
 #include "defs.h"
 
-ALIAS(getcontext, __getcontext)
+ALIAS(getcontext, libucontext_getcontext)
+ALIAS(__getcontext, libucontext_getcontext)
 
-FUNC(__getcontext)
+FUNC(libucontext_getcontext)
 	/* copy all of the current registers into the ucontext structure */
 	add	r1, r0, #REG_OFFSET(4)
 	stmia	r1, {r4-r12}
 	str	r13, [r0, #REG_OFFSET(13)]
 	str	r14, [r0, #REG_OFFSET(15)]
 
+#ifndef FORCE_SOFT_FLOAT
+#ifndef FORCE_HARD_FLOAT
+        /* test for vfp, set kernel-defined magic number in uc_regspace */
+        push    {r0-r1,fp,lr}
+        mov     r0, #16
+        bl      getauxval
+        tst     r0, #64
+        pop     {r0-r1,fp,lr}
+	moveq	r2, #0
+	ldrne	r2, =#0x56465001
+	str	r2, [r0, #VFP_MAGIC_OFFSET]
+        beq     1f
+#endif
+	/* if vfp detected, save d8-d15 */
+	.fpu	vfp
+	add	r1, r0, #VFP_D8_OFFSET
+	vstmia	r1, {d8-d15}
+	.fpu	softvfp
+1:
+#endif
+
 	/* return 0 */
 	mov	r0, #0
 	mov	pc, lr
-END(__getcontext)
+END(libucontext_getcontext)

arch/arm/include/libucontext/bits.h

@@ -0,0 +1,30 @@
+#ifndef LIBUCONTEXT_BITS_H
+#define LIBUCONTEXT_BITS_H
+
+typedef int libucontext_greg_t, libucontext_gregset_t[18];
+
+typedef struct {
+	unsigned long trap_no, error_code, oldmask;
+	unsigned long arm_r0, arm_r1, arm_r2, arm_r3;
+	unsigned long arm_r4, arm_r5, arm_r6, arm_r7;
+	unsigned long arm_r8, arm_r9, arm_r10, arm_fp;
+	unsigned long arm_ip, arm_sp, arm_lr, arm_pc;
+	unsigned long arm_cpsr, fault_address;
+} libucontext_mcontext_t;
+
+typedef struct {
+	void *ss_sp;
+	int ss_flags;
+	size_t ss_size;
+} libucontext_stack_t;
+
+typedef struct libucontext_ucontext {
+	unsigned long uc_flags;
+	struct libucontext_ucontext *uc_link;
+	libucontext_stack_t uc_stack;
+	libucontext_mcontext_t uc_mcontext;
+	unsigned long uc_sigmask[128 / sizeof(long)];
+	unsigned long long uc_regspace[64];
+} libucontext_ucontext_t;
+
+#endif

arch/arm/makecontext.c

@@ -10,23 +10,22 @@
  * from the use of this software.
  */
 
-#define _GNU_SOURCE
 #include <stddef.h>
 #include <stdarg.h>
-#include <signal.h>
 #include <string.h>
 #include <stdint.h>
 #include <stdio.h>
 
 
 #include "defs.h"
+#include <libucontext/libucontext.h>
 
 
-extern void __start_context(void);
+extern void libucontext_trampoline(void);
 
 
 void
-__makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
+libucontext_makecontext(libucontext_ucontext_t *ucp, void (*func)(void), int argc, ...)
 {
 	unsigned long *sp;
 	unsigned long *regp;
@@ -42,7 +41,7 @@ __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
 	ucp->uc_mcontext.arm_sp = (uintptr_t) sp;
 	ucp->uc_mcontext.arm_pc = (uintptr_t) func;
 	ucp->uc_mcontext.arm_r4 = (uintptr_t) ucp->uc_link;
-	ucp->uc_mcontext.arm_lr = (uintptr_t) &__start_context;
+	ucp->uc_mcontext.arm_lr = (uintptr_t) &libucontext_trampoline;
 
 	va_start(va, argc);
 
@@ -57,5 +56,7 @@ __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
 	va_end(va);
 }
 
-
-extern __typeof(__makecontext) makecontext __attribute__((weak, __alias__("__makecontext")));
+#ifdef EXPORT_UNPREFIXED
+extern __typeof(libucontext_makecontext) makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+extern __typeof(libucontext_makecontext) __makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+#endif

arch/arm/setcontext.S

@@ -12,9 +12,26 @@
 
 #include "defs.h"
 
-ALIAS(setcontext, __setcontext)
+ALIAS(setcontext, libucontext_setcontext)
+ALIAS(__setcontext, libucontext_setcontext)
+
+FUNC(libucontext_setcontext)
+#ifndef FORCE_SOFT_FLOAT
+#ifndef FORCE_HARD_FLOAT
+	/* test for vfp magic number set by getcontext */
+	ldr	r2, [r0, #VFP_MAGIC_OFFSET]
+	ldr	r3, =#0x56465001
+	cmp	r2, r3
+        bne     1f
+#endif
+	/* if vfp in use, restore d8-d15 from uc_regspace */
+	.fpu	vfp
+	add	r14, r0, #VFP_D8_OFFSET
+	vldmia	r14, {d8-d15}
+	.fpu 	softvfp
+1:
+#endif
 
-FUNC(__setcontext)
 	/* copy all of the current registers into the ucontext structure */
 	add	r14, r0, #REG_OFFSET(0)
 	ldmia	r14, {r0-r12}
@@ -23,4 +40,4 @@ FUNC(__setcontext)
 
 	/* load link register and jump to new context */
 	ldmia	r14, {r14, pc}
-END(__setcontext)
+END(libucontext_setcontext)

arch/arm/startcontext.S

@@ -1,23 +0,0 @@
-/*
- * Copyright (c) 2018 Ariadne Conill <ariadne@dereferenced.org>
- *
- * Permission to use, copy, modify, and/or distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * This software is provided 'as is' and without any warranty, express or
- * implied.  In no event shall the authors be liable for any damages arising
- * from the use of this software.
- */
-
-.globl __start_context;
-.fnstart
-.cantunwind
-	nop
-__start_context:
-	/* get the proper context into position and test for NULL */
-	movs	r0, r4
-	bne	__setcontext@plt
-
-	/* we are returning into a null context, it seems, so maybe we should exit */
-	b	exit@plt

arch/arm/swapcontext.S

@@ -12,19 +12,40 @@
 
 #include "defs.h"
 
-ALIAS(swapcontext, __swapcontext)
+ALIAS(swapcontext, libucontext_swapcontext)
+ALIAS(__swapcontext, libucontext_swapcontext)
 
-FUNC(__swapcontext)
+FUNC(libucontext_swapcontext)
 	/* copy all of the current registers into the ucontext structure */
 	add	r2, r0, #REG_OFFSET(0)
 	stmia	r2, {r0-r12}
 	str	r13, [r0,#REG_OFFSET(13)]
 	str	r14, [r0,#REG_OFFSET(15)]
 
+#ifndef FORCE_SOFT_FLOAT
+#ifndef FORCE_HARD_FLOAT
+	/* test for vfp magic number, copy to other ucontext */
+	ldr	r3, [r1, #VFP_MAGIC_OFFSET]
+	ldr	r4, =#0x56465001
+	str	r3, [r0, #VFP_MAGIC_OFFSET]
+	cmp	r3, r4
+	bne	1f
+#endif
+	/* if vfp in use, save and restore d8-d15 */
+	.fpu	vfp
+	add	r2, r0, #VFP_D8_OFFSET
+	vstmia	r2, {d8-d15}
+
+	add	r14, r1, #VFP_D8_OFFSET
+	vldmia	r14, {d8-d15}
+	.fpu	softvfp
+1:
+#endif
+
 	/* load new registers from the second ucontext structure */
 	add	r14, r1, #REG_OFFSET(0)
 	ldmia	r14, {r0-r12}
 	ldr	r13, [r14, #52]
 	add	r14, r14, #56
 	ldmia	r14, {r14, pc}
-END(__swapcontext)
+END(libucontext_swapcontext)

arch/arm/trampoline.c

@@ -0,0 +1,3 @@
+#include "defs.h"
+#include <libucontext/libucontext.h>
+#include "common-trampoline.c"

arch/common/common-defs.h

@@ -18,15 +18,27 @@
 #endif
 
 #ifndef TYPE
-# define TYPE(__proc)	.type	__proc, @function;
+# ifdef __clang__
+#  define TYPE(__proc) // .type not supported
+# else
+#  define TYPE(__proc)	.type	__proc, @function;
+#endif
+#endif
+
+#ifndef PROC_NAME
+# ifdef __MACH__
+#  define PROC_NAME(__proc) _ ## __proc
+# else
+#  define PROC_NAME(__proc) __proc
+# endif
 #endif
 
 #define FUNC(__proc)					\
-	.global __proc;					\
+	.global PROC_NAME(__proc);			\
 	.align  2;					\
 	TYPE(__proc)					\
 	ENT(__proc)					\
-__proc:							\
+PROC_NAME(__proc):					\
 	SETUP_FRAME(__proc)
 #ifdef __clang__
 #define END(__proc)
@@ -36,9 +48,13 @@ __proc:							\
 	.size	__proc,.-__proc;
 #endif
 
+#ifdef EXPORT_UNPREFIXED
 #define ALIAS(__alias, __real)				\
 	.weak	__alias;				\
 	__alias = __real;
+#else
+#define ALIAS(...)
+#endif
 
 #define REG_OFFSET(__reg)       (MCONTEXT_GREGS + ((__reg) * REG_SZ))
 

arch/common/common-trampoline.c

@@ -10,20 +10,20 @@
  * from the use of this software.
  */
 
-#include "defs.h"
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
 
-FUNC(__start_context)
-	/* call the function passed to makecontext() */
-	jalr	s1
+__attribute__ ((visibility ("hidden")))
+void
+libucontext_trampoline(void)
+{
+	register libucontext_ucontext_t *uc_link = NULL;
 
-	/* check for linked context */
-	beqz	s2, no_linked_context
+	FETCH_LINKPTR(uc_link);
 
-	/* if one is set, invoke it */
-	mv	a0, s2
-	jal	__setcontext
+	if (uc_link == NULL)
+		exit(0);
 
-	/* otherwise, exit. */
-no_linked_context:
-	j	exit
-END(__start_context)
+	libucontext_setcontext(uc_link);
+}

arch/common/include/libucontext/bits.h

@@ -0,0 +1,13 @@
+#ifndef LIBUCONTEXT_BITS_H
+#define LIBUCONTEXT_BITS_H
+
+#ifndef FREESTANDING
+
+#include <ucontext.h>
+
+typedef greg_t libucontext_greg_t;
+typedef ucontext_t libucontext_ucontext_t;
+
+#endif
+
+#endif

arch/loongarch64/defs.h

@@ -0,0 +1,76 @@
+#ifndef __ARCH_LOONGARCH64_DEFS_H
+#define __ARCH_LOONGARCH64_DEFS_H
+
+#define REG_SZ		(8)
+
+#define REG_R0		(0)
+#define REG_R1		(1)
+#define REG_R2		(2)
+#define REG_R3		(3)
+#define REG_R4		(4)
+#define REG_R5		(5)
+#define REG_R6		(6)
+#define REG_R7		(7)
+#define REG_R8		(8)
+#define REG_R9		(9)
+#define REG_R10		(10)
+#define REG_R11		(11)
+#define REG_R12		(12)
+#define REG_R13		(13)
+#define REG_R14		(14)
+#define REG_R15		(15)
+#define REG_R16		(16)
+#define REG_R17		(17)
+#define REG_R18		(18)
+#define REG_R19		(19)
+#define REG_R20		(20)
+#define REG_R21		(21)
+#define REG_R22		(22)
+#define REG_R23		(23)
+#define REG_R24		(24)
+#define REG_R25		(25)
+#define REG_R26		(26)
+#define REG_R27		(27)
+#define REG_R28		(28)
+#define REG_R29		(29)
+#define REG_R30		(30)
+#define REG_R31		(31)
+
+/* $a0 is $4 , also $v0, same as $5, $a1 and $v1*/
+#define REG_A0		(4)
+
+/* stack pointer is actually $3 */
+#define REG_SP		(3)
+
+/* frame pointer is actually $22 */
+#define REG_FP		(22)
+
+/* offset to mc_gregs in ucontext_t */
+#define MCONTEXT_GREGS	(48)
+
+/* offset to PC in ucontext_t */
+#define MCONTEXT_PC	(40)
+
+/* offset to uc_link in ucontext_t */
+#define UCONTEXT_UC_LINK	(8)
+
+/* offset to uc_stack.ss_sp in ucontext_t */
+#define UCONTEXT_STACK_PTR	(16)
+
+/* offset to uc_stack.ss_size in ucontext_t */
+#define UCONTEXT_STACK_SIZE	(32)
+
+/* Stack alignment, from Kernel source */
+#define ALSZ		15
+#define ALMASK		~15
+#define FRAMESZ		(((LOCALSZ * REG_SZ) + ALSZ) & ALMASK)
+
+#define PUSH_FRAME(__proc)	\
+	addi.d		$sp, $sp, -FRAMESZ;
+
+#define POP_FRAME(__proc)	\
+	addi.d		$sp, $sp, FRAMESZ;
+
+#include <common-defs.h>
+
+#endif

arch/loongarch64/freestanding/bits.h

@@ -0,0 +1,43 @@
+#ifndef LIBUCONTEXT_BITS_H
+#define LIBUCONTEXT_BITS_H
+
+typedef unsigned long long libucontext_greg_t, libucontext_gregset_t[32];
+
+/* Container for all general registers.  */
+typedef __loongarch_mc_gp_state gregset_t;
+
+/* Container for floating-point state.  */
+typedef union __loongarch_mc_fp_state fpregset_t;
+
+union __loongarch_mc_fp_state {
+    unsigned int   __val32[256 / 32];
+    unsigned long long   __val64[256 / 64];
+};
+
+typedef struct mcontext_t {
+    unsigned long long   __pc;
+    unsigned long long   __gregs[32];
+    unsigned int   __flags;
+
+    unsigned int   __fcsr;
+    unsigned int   __vcsr;
+    unsigned long long   __fcc;
+    union __loongarch_mc_fp_state    __fpregs[32] __attribute__((__aligned__ (32)));
+
+    unsigned int   __reserved;
+} mcontext_t;
+
+typedef struct {
+	void *ss_sp;
+	int ss_flags;
+	size_t ss_size;
+} libucontext_stack_t;
+
+typedef struct libucontext_ucontext {
+	unsigned long uc_flags;
+	struct libucontext_ucontext *uc_link;
+	libucontext_stack_t uc_stack;
+	libucontext_mcontext_t uc_mcontext;
+} libucontext_ucontext_t;
+
+#endif

arch/loongarch64/getcontext.S

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2021 Peng Fan <fanpeng@loongson.cn>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#define LOCALSZ (1)
+
+#include "defs.h"
+
+ALIAS(getcontext, libucontext_getcontext)
+
+FUNC(libucontext_getcontext)
+	/* copy $sp, $fp to temporary registers so we don't clobber them */
+	move	$a2, $sp
+	move	$a3, $fp
+
+	PUSH_FRAME(libucontext_getcontext)
+
+	/* set registers */
+	st.d	$s0, $a0, REG_OFFSET(23)
+	st.d	$s1, $a0, REG_OFFSET(24)
+	st.d	$s2, $a0, REG_OFFSET(25)
+	st.d	$s3, $a0, REG_OFFSET(26)
+	st.d	$s4, $a0, REG_OFFSET(27)
+	st.d	$s5, $a0, REG_OFFSET(28)
+	st.d	$s6, $a0, REG_OFFSET(29)
+	st.d	$s7, $a0, REG_OFFSET(30)
+	st.d	$s8, $a0, REG_OFFSET(31)
+
+	st.d	$a2, $a0, REG_OFFSET(3)
+	st.d	$a3, $a0, REG_OFFSET(22)
+	st.d	$ra, $a0, REG_OFFSET(1)
+
+	st.d	$ra, $a0, (MCONTEXT_PC)
+
+	POP_FRAME(libucontext_getcontext)
+
+	jr	$ra
+END(libucontext_getcontext)

arch/loongarch64/makecontext.S

@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2021 Peng Fan <fanpeng@loongson.cn>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include "defs.h"
+
+#define LOCALSZ (6)
+
+#define A3_OFF (FRAMESZ - (5 * REG_SZ))
+#define A4_OFF (FRAMESZ - (4 * REG_SZ))
+#define A5_OFF (FRAMESZ - (3 * REG_SZ))
+#define A6_OFF (FRAMESZ - (2 * REG_SZ))
+#define A7_OFF (FRAMESZ - (1 * REG_SZ))
+
+ALIAS(makecontext, libucontext_makecontext)
+
+FUNC(libucontext_makecontext)
+	PUSH_FRAME(libucontext_makecontext)
+
+	move	$t5, $a0
+	move	$t4, $a1
+
+	/* store $a3 through $a7 to the stack frame. */
+	st.d	$a3, $sp, A3_OFF
+	st.d	$a4, $sp, A4_OFF
+	st.d	$a5, $sp, A5_OFF
+	st.d	$a6, $sp, A6_OFF
+	st.d	$a7, $sp, A7_OFF
+
+	/* set $zero in the mcontext to 1. */
+	addi.d	$v0, $zero, 1
+	st.d	$v0, $t5, REG_OFFSET(0)
+
+	/* ensure the stack is aligned on a quad-word boundary. */
+	ld.d	$t0, $t5, UCONTEXT_STACK_PTR
+	ld.d	$t2, $t5, UCONTEXT_STACK_SIZE
+	/* the third argument(from zero), that's the first argument of func() */
+	addi.d	$t1, $sp, A3_OFF
+	add.d	$t0, $t0, $t2
+
+	addi.d	$t7, $zero, ALMASK
+	and	$t0, $t0, $t7
+
+	/* number of args */
+	beq	$a2, $zero, no_more_arguments
+	bltu	$a2, $zero, no_more_arguments
+
+	/* store register arguments. */
+	addi.d	$t2, $t5, MCONTEXT_GREGS + (4 * REG_SZ)
+	move	$t3, $zero
+
+store_register_arg:
+	addi.d	$t3, $t3, 1
+	ld.d	$v1, $t1, 0
+	addi.d	$t1, $t1, REG_SZ
+	st.d	$v1, $t2, 0
+	addi.d	$t2, $t2, REG_SZ
+	addi.d	$t6, $zero, 8
+	bltu	$t3, $t6, store_register_arg
+	bgeu	$t3, $a2, no_more_arguments
+
+	/* make room for stack arguments. */
+	sub.d	$t2, $a2, $t3
+
+	addi.d	$t6, $zero, 3
+	sll.d	$t2, $t2, $t6
+
+	sub.d	$t0, $t0, $t2
+
+	addi.d	$t6, $zero, ALMASK
+	and	$t0, $t0, $t6
+
+	/* store stack arguments. */
+	move	$t2, $t0
+
+store_stack_arg:
+	addi.d	$t3, $t3, 1
+	ld.d	$v1, $t1, 0
+	addi.d	$t1, $t1, REG_SZ
+	st.d	$v1, $t2, 0
+	addi.d	$t2, $t2, REG_SZ
+	bltu	$t3, $a2, store_stack_arg
+
+no_more_arguments:
+	/* trampoline setup. */
+	la.got	$t8, libucontext_trampoline
+
+	ld.d	$v1, $t5, UCONTEXT_UC_LINK
+	st.d	$v1, $t5, REG_OFFSET(23)
+
+	st.d	$t0, $t5, REG_OFFSET(3)
+
+	st.d	$t8, $t5, REG_OFFSET(1)
+
+	st.d	$t4, $t5, MCONTEXT_PC
+
+	POP_FRAME(libucontext_makecontext)
+
+	jr	$ra
+END(libucontext_makecontext)

arch/loongarch64/setcontext.S

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2021 Peng Fan <fanpeng@loongson.cn>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#define LOCALSZ (1)
+
+#include "defs.h"
+
+ALIAS(setcontext, libucontext_setcontext)
+
+FUNC(libucontext_setcontext)
+	PUSH_FRAME(libucontext_setcontext)
+
+	/* move the context to $v0, in LA, $v0 = $a0 = $4 */
+	move	$t5, $a0
+
+	/* load the registers */
+	ld.d	$a0, $t5, REG_OFFSET(4)
+	ld.d	$a1, $t5, REG_OFFSET(5)
+	ld.d	$a2, $t5, REG_OFFSET(6)
+	ld.d	$a3, $t5, REG_OFFSET(7)
+	ld.d	$a4, $t5, REG_OFFSET(8)
+	ld.d	$a5, $t5, REG_OFFSET(9)
+	ld.d	$a6, $t5, REG_OFFSET(10)
+	ld.d	$a7, $t5, REG_OFFSET(11)
+
+	ld.d	$s0, $t5, REG_OFFSET(23)
+	ld.d	$s1, $t5, REG_OFFSET(24)
+	ld.d	$s2, $t5, REG_OFFSET(25)
+	ld.d	$s3, $t5, REG_OFFSET(26)
+	ld.d	$s4, $t5, REG_OFFSET(27)
+	ld.d	$s5, $t5, REG_OFFSET(28)
+	ld.d	$s6, $t5, REG_OFFSET(29)
+	ld.d	$s7, $t5, REG_OFFSET(30)
+	ld.d	$s8, $t5, REG_OFFSET(31)
+
+	ld.d	$sp, $t5, REG_OFFSET(3)
+	ld.d	$fp, $t5, REG_OFFSET(22)
+	ld.d	$ra, $t5, REG_OFFSET(1)
+
+	ld.d	$t8, $t5, (MCONTEXT_PC)
+
+	jr	$t8
+	move	$v0, $zero
+
+	POP_FRAME(libucontext_setcontext)
+END(libucontext_setcontext)

arch/loongarch64/startcontext.S

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018 Ariadne Conill <ariadne@dereferenced.org>
+ * Copyright (c) 2021 Peng Fan <fanpeng@loongson.cn>
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -10,13 +10,24 @@
  * from the use of this software.
  */
 
+#define LOCALSZ (4)
+
 #include "defs.h"
 
-FUNC(__start_context)
-	/* get the proper context into position and test for NULL */
-	mov	x0, x19
-	cbnz	x0, __setcontext
+FUNC(libucontext_trampoline)
 
-	/* something went wrong, exit */
-	b	exit
-END(__start_context)
+	/* call setcontext */
+	move	$a0, $s0
+	/* we receive our initial ucontext in $s0, so if $s0 is nil, bail */
+	beqz	$s0, no_linked_context
+
+	la.got	$t8, libucontext_setcontext
+
+	jr	$t8
+
+no_linked_context:
+	move	$a0, $zero
+	la.global	$t8, exit
+	jr	$t8
+
+END(libucontext_trampoline)

arch/loongarch64/swapcontext.S

@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2021 Peng Fan <fanpeng@loongson.cn>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#define	LOCALSZ	(4)
+
+#include "defs.h"
+
+#define A1_OFFSET (FRAMESZ - (1 * REG_SZ))
+
+ALIAS(swapcontext, libucontext_swapcontext)
+
+FUNC(libucontext_swapcontext)
+	/* copy $sp, $fp to temporary registers so we don't clobber them */
+	move	$a3, $sp
+	move	$a4, $fp
+
+	move	$t5, $a0
+
+	PUSH_FRAME(libucontext_swapcontext)
+
+	/* set registers */
+	st.d	$s0, $t5, REG_OFFSET(23)
+	st.d	$s1, $t5, REG_OFFSET(24)
+	st.d	$s2, $t5, REG_OFFSET(25)
+	st.d	$s3, $t5, REG_OFFSET(26)
+	st.d	$s4, $t5, REG_OFFSET(27)
+	st.d	$s5, $t5, REG_OFFSET(28)
+	st.d	$s6, $t5, REG_OFFSET(29)
+	st.d	$s7, $t5, REG_OFFSET(30)
+	st.d	$s8, $t5, REG_OFFSET(31)
+
+	st.d	$a3, $t5, REG_OFFSET(3)
+	st.d	$a4, $t5, REG_OFFSET(22)
+	st.d	$ra, $t5, REG_OFFSET(1)
+
+	st.d	$ra, $t5, (MCONTEXT_PC)
+
+	/* copy new context address in $a1 to stack */
+	st.d	$a1, $sp, A1_OFFSET
+
+	/* load new context address into $v0 */
+	ld.d	$t4, $sp, A1_OFFSET
+
+	/* load the registers */
+	ld.d	$a0, $t4, REG_OFFSET(4)
+	ld.d	$a1, $t4, REG_OFFSET(5)
+	ld.d	$a2, $t4, REG_OFFSET(6)
+	ld.d	$a3, $t4, REG_OFFSET(7)
+	ld.d	$a4, $t4, REG_OFFSET(8)
+	ld.d	$a5, $t4, REG_OFFSET(9)
+	ld.d	$a6, $t4, REG_OFFSET(10)
+	ld.d	$a7, $t4, REG_OFFSET(11)
+
+	ld.d	$s0, $t4, REG_OFFSET(23)
+	ld.d	$s1, $t4, REG_OFFSET(24)
+	ld.d	$s2, $t4, REG_OFFSET(25)
+	ld.d	$s3, $t4, REG_OFFSET(26)
+	ld.d	$s4, $t4, REG_OFFSET(27)
+	ld.d	$s5, $t4, REG_OFFSET(28)
+	ld.d	$s6, $t4, REG_OFFSET(29)
+	ld.d	$s7, $t4, REG_OFFSET(30)
+	ld.d	$s8, $t4, REG_OFFSET(31)
+
+	ld.d	$sp, $t4, REG_OFFSET(3)
+	ld.d	$fp, $t4, REG_OFFSET(22)
+	ld.d	$ra, $t4, REG_OFFSET(1)
+
+	ld.d	$t8, $t4, (MCONTEXT_PC)
+
+	jr	$t8
+	move	$v0, $zero
+
+fail:
+	la.global	$t8, exit
+
+	POP_FRAME(libucontext_swapcontext)
+
+	jirl	$ra, $t8, 0
+	move	$v0, $zero
+END(libucontext_swapcontext)

arch/m68k/defs.h

@@ -0,0 +1,34 @@
+#ifndef __ARCH_M68K_DEFS_H
+#define __ARCH_M68K_DEFS_H
+
+#define REG_SZ		(4)
+#define MCONTEXT_GREGS	(24)
+
+#define REG_D0		(0)
+#define REG_D1		(1)
+#define REG_D2		(2)
+#define REG_D3		(3)
+#define REG_D4		(4)
+#define REG_D5		(5)
+#define REG_D6		(6)
+#define REG_D7		(7)
+#define REG_A0		(8)
+#define REG_A1		(9)
+#define REG_A2		(10)
+#define REG_A3		(11)
+#define REG_A4		(12)
+#define REG_A5		(13)
+#define REG_A6		(14)
+#define REG_A7		(15)
+#define REG_SP		(15)
+#define REG_PC		(16)
+#define REG_PS		(17)
+
+#define PC_OFFSET	REG_OFFSET(REG_PC)
+
+#define FETCH_LINKPTR(dest) \
+	asm("mov.l (%%sp, %%d7.l * 4), %0" :: "r" ((dest)))
+
+#include "common-defs.h"
+
+#endif

arch/m68k/getcontext.S

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include "defs.h"
+
+ALIAS(getcontext, libucontext_getcontext)
+ALIAS(__getcontext, libucontext_getcontext)
+
+FUNC(libucontext_getcontext)
+	move.l		4(%sp), %a0				/* load ucontext_t pointer from stack */
+
+	movem.l		%d2-%d7, REG_OFFSET(REG_D2)(%a0)	/* preserve $d2 through $d7 */
+	movem.l		%a2-%a6, REG_OFFSET(REG_A2)(%a0)	/* preserve $a2 through $a6 */
+
+	lea		4(%sp), %a1				/* load stack pointer into $a1 */
+	move.l		%a1, REG_OFFSET(REG_SP)(%a0)		/* store $a1 in ucontext */
+	move.l		(%sp), REG_OFFSET(REG_PC)(%a0)		/* store return address in ucontext's PC register */
+
+	clr.l		%d0					/* return 0 */
+	rts
+END(libucontext_getcontext)

arch/m68k/include/libucontext/bits.h

@@ -0,0 +1,28 @@
+#ifndef LIBUCONTEXT_BITS_H
+#define LIBUCONTEXT_BITS_H
+
+typedef struct sigaltstack {
+	void *ss_sp;
+	int ss_flags;
+	size_t ss_size;
+} libucontext_stack_t;
+
+typedef int libucontext_greg_t, libucontext_gregset_t[18];
+typedef struct {
+	int f_pcr, f_psr, f_fpiaddr, f_fpregs[8][3];
+} libucontext_fpregset_t;
+
+typedef struct {
+	int version;
+	libucontext_gregset_t gregs;
+	libucontext_fpregset_t fpregs;
+} libucontext_mcontext_t;
+
+typedef struct libucontext_ucontext {
+	unsigned long uc_flags;
+	struct libucontext_ucontext *uc_link;
+	libucontext_stack_t uc_stack;
+	libucontext_mcontext_t uc_mcontext;
+} libucontext_ucontext_t;
+
+#endif

arch/m68k/makecontext.c

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include <stddef.h>
+#include <stdarg.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdio.h>
+#include "defs.h"
+#include <libucontext/libucontext.h>
+
+
+extern void libucontext_trampoline(void);
+
+
+void
+libucontext_makecontext(libucontext_ucontext_t *ucp, void (*func)(void), int argc, ...)
+{
+	libucontext_greg_t *sp;
+	va_list va;
+	int i;
+
+	/* set up and align the stack. */
+	sp = (libucontext_greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
+	sp -= (argc + 2);
+	sp = (libucontext_greg_t *) (((uintptr_t) sp & ~0x3));
+
+	/* set up the ucontext structure */
+	ucp->uc_mcontext.gregs[REG_SP] = (libucontext_greg_t) sp;
+	ucp->uc_mcontext.gregs[REG_A6] = 0;
+	ucp->uc_mcontext.gregs[REG_D7] = argc;
+	ucp->uc_mcontext.gregs[REG_PC] = (libucontext_greg_t) func;
+
+	/* return address */
+	*sp++ = (libucontext_greg_t) libucontext_trampoline;
+
+	va_start(va, argc);
+
+	/* all arguments overflow into stack */
+	for (i = 0; i < argc; i++)
+		*sp++ = va_arg (va, libucontext_greg_t);
+
+	va_end(va);
+
+	/* link pointer */
+	*sp++ = (libucontext_greg_t) ucp->uc_link;
+}
+
+#ifdef EXPORT_UNPREFIXED
+extern __typeof(libucontext_makecontext) makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+extern __typeof(libucontext_makecontext) __makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+#endif

arch/m68k/setcontext.S

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include "defs.h"
+
+ALIAS(setcontext, libucontext_setcontext)
+ALIAS(__setcontext, libucontext_setcontext)
+
+FUNC(libucontext_setcontext)
+	move.l		4(%sp), %a0				/* load ucontext_t pointer from stack */
+
+	move.l		REG_OFFSET(REG_SP)(%a0), %sp		/* load new stack pointer */
+
+	movem.l		REG_OFFSET(REG_D2)(%a0), %d2-%d7	/* load $d2 through $d7 */
+	movem.l		REG_OFFSET(REG_A2)(%a0), %a2-%a6	/* load $a2 through $a6 */
+
+	clr.l		%d0					/* clear $d0 */
+
+	move.l		REG_OFFSET(REG_PC)(%a0), %a1		/* load jump target */
+
+	jmp		(%a1)					/* jump to *$a1 */
+END(libucontext_setcontext)

arch/m68k/swapcontext.S

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include "defs.h"
+
+ALIAS(swapcontext, libucontext_swapcontext)
+ALIAS(__swapcontext, libucontext_swapcontext)
+
+FUNC(libucontext_swapcontext)
+	move.l		4(%sp), %a0				/* load save ucontext_t pointer from stack */
+
+	movem.l		%d2-%d7, REG_OFFSET(REG_D2)(%a0)	/* preserve $d2 through $d7 */
+	movem.l		%a2-%a6, REG_OFFSET(REG_A2)(%a0)	/* preserve $a2 through $a6 */
+
+	lea		4(%sp), %a1				/* load stack pointer into $a1 */
+	move.l		%a1, REG_OFFSET(REG_SP)(%a0)		/* store $a1 in ucontext */
+	move.l		(%sp), REG_OFFSET(REG_PC)(%a0)		/* store return address in ucontext's PC register */
+
+	move.l		8(%sp), %a0				/* load new ucontext_t pointer from stack */
+
+	move.l		REG_OFFSET(REG_SP)(%a0), %sp		/* load new stack pointer */
+
+	movem.l		REG_OFFSET(REG_D2)(%a0), %d2-%d7	/* load $d2 through $d7 */
+	movem.l		REG_OFFSET(REG_A2)(%a0), %a2-%a6	/* load $a2 through $a6 */
+
+	clr.l		%d0					/* clear $d0 */
+
+	move.l		REG_OFFSET(REG_PC)(%a0), %a1		/* load jump target */
+
+	jmp		(%a1)					/* jump to *$a1 */
+END(libucontext_swapcontext)

arch/m68k/trampoline.c

@@ -0,0 +1,3 @@
+#include "defs.h"
+#include <libucontext/libucontext.h>
+#include "common-trampoline.c"

arch/mips/getcontext.S

@@ -14,15 +14,16 @@ LOCALSZ = 1
 
 #include "defs.h"
 
-ALIAS(getcontext, __getcontext)
+ALIAS(getcontext, libucontext_getcontext)
+ALIAS(__getcontext, libucontext_getcontext)
 
-FUNC(__getcontext)
+FUNC(libucontext_getcontext)
 	/* copy $gp, $sp, $fp to temporary registers so we don't clobber them */
 	move	$a2, $gp
 	move	$a3, $sp
 	move	$a1, $fp
 
-	PUSH_FRAME(__getcontext)
+	PUSH_FRAME(libucontext_getcontext)
 
 	/* set registers */
 	sw	$s0, REG_OFFSET(16)($a0)
@@ -40,7 +41,7 @@ FUNC(__getcontext)
 	sw	$ra, REG_OFFSET(31)($a0)
 	sw	$ra, (MCONTEXT_PC)($a0)
 
-	POP_FRAME(__getcontext)
+	POP_FRAME(libucontext_getcontext)
 
 	jr	$ra
-END(__getcontext)
+END(libucontext_getcontext)

arch/mips/include/libucontext/bits.h

@@ -0,0 +1,27 @@
+#ifndef LIBUCONTEXT_BITS_H
+#define LIBUCONTEXT_BITS_H
+
+typedef unsigned long long libucontext_greg_t, libucontext_gregset_t[32];
+
+typedef struct {
+	unsigned regmask, status;
+	unsigned long long pc, gregs[32], fpregs[32];
+	unsigned ownedfp, fpc_csr, fpc_eir, used_math, dsp;
+	unsigned long long mdhi, mdlo;
+	unsigned long hi1, lo1, hi2, lo2, hi3, lo3;
+} libucontext_mcontext_t;
+
+typedef struct {
+	void *ss_sp;
+	size_t ss_size;
+	int ss_flags;
+} libucontext_stack_t;
+
+typedef struct libucontext_ucontext {
+	unsigned long uc_flags;
+	struct libucontext_ucontext *uc_link;
+	libucontext_stack_t uc_stack;
+	libucontext_mcontext_t uc_mcontext;
+} libucontext_ucontext_t;
+
+#endif

arch/mips/makecontext.S

@@ -21,10 +21,11 @@ A3_OFF = FRAMESZ + (3 * REG_SZ)
  * assembly rather than C.  Annoying, that...
  */
 
-ALIAS(makecontext, __makecontext)
+ALIAS(makecontext, libucontext_makecontext)
+ALIAS(__makecontext, libucontext_makecontext)
 
-FUNC(__makecontext)
-	PUSH_FRAME(__makecontext)
+FUNC(libucontext_makecontext)
+	PUSH_FRAME(libucontext_makecontext)
 
 	/* store $a3 through $a7 to the stack frame. */
 	sw	$a3, A3_OFF($sp)
@@ -76,7 +77,7 @@ no_more_arguments:
 	addiu	$t0, -(4 * REG_SZ)
 
 	/* trampoline setup. */
-	la	$t9, __start_context
+	la	$t9, libucontext_trampoline
 
 	/* copy link pointer as $s0... */
 	lw	$v1, UCONTEXT_UC_LINK($a0)
@@ -94,7 +95,7 @@ no_more_arguments:
 	/* set our $pc */
 	sw	$a1, MCONTEXT_PC($a0)
 
-	POP_FRAME(__makecontext)
+	POP_FRAME(libucontext_makecontext)
 
 	jr	$ra
-END(__makecontext)
+END(libucontext_makecontext)

arch/mips/setcontext.S

@@ -14,10 +14,11 @@ LOCALSZ = 1
 
 #include "defs.h"
 
-ALIAS(setcontext, __setcontext)
+ALIAS(setcontext, libucontext_setcontext)
+ALIAS(__setcontext, libucontext_setcontext)
 
-FUNC(__setcontext)
-	PUSH_FRAME(__setcontext)
+FUNC(libucontext_setcontext)
+	PUSH_FRAME(libucontext_setcontext)
 
 	/* move the context to $v0 */	
 	move	$v0, $a0
@@ -46,5 +47,5 @@ FUNC(__setcontext)
 	move	$v0, $zero
 	jr	$t9
 
-	POP_FRAME(__setcontext)
-END(__setcontext)
+	POP_FRAME(libucontext_setcontext)
+END(libucontext_setcontext)

arch/mips/startcontext.S

@@ -14,7 +14,8 @@ LOCALSZ = 1
 
 #include "defs.h"
 
-FUNC(__start_context)
+.hidden libucontext_trampoline
+FUNC(libucontext_trampoline)
 	move	$gp, $s1
 
 	/* we receive our initial ucontext in $s0, so if $s0 is nil, bail */
@@ -22,7 +23,7 @@ FUNC(__start_context)
 
 	/* call setcontext */
 	move	$a0, $s0
-	la	$t9, __setcontext
+	la	$t9, PROC_NAME(libucontext_setcontext)
 
 	jr	$t9
 
@@ -31,4 +32,4 @@ no_linked_context:
 	la	$t9, exit
 	jalr	$t9
 	nop
-END(__start_context)
+END(libucontext_trampoline)

arch/mips/swapcontext.S

@@ -16,14 +16,15 @@ LOCALSZ = 2
 
 A1_OFFSET = FRAMESZ - (1 * REG_SZ)
 
-ALIAS(swapcontext, __swapcontext)
+ALIAS(swapcontext, libucontext_swapcontext)
+ALIAS(__swapcontext, libucontext_swapcontext)
 
-FUNC(__swapcontext)
+FUNC(libucontext_swapcontext)
 	/* copy $gp, $sp, $fp to temporary registers so we don't clobber them */
 	move	$a2, $gp
 	move	$a3, $sp
 
-	PUSH_FRAME(__swapcontext)
+	PUSH_FRAME(libucontext_swapcontext)
 
 	/* set registers */
 	sd	$s0, REG_OFFSET(16)($a0)
@@ -74,8 +75,8 @@ FUNC(__swapcontext)
 fail:
 	la	$t9, exit
 
-	POP_FRAME(__swapcontext)
+	POP_FRAME(libucontext_swapcontext)
 
 	move	$v0, $zero
 	jalr	$t9
-END(__swapcontext)
+END(libucontext_swapcontext)

arch/mips64/getcontext.S

@@ -14,15 +14,16 @@ LOCALSZ = 1
 
 #include "defs.h"
 
-ALIAS(getcontext, __getcontext)
+ALIAS(getcontext, libucontext_getcontext)
+ALIAS(__getcontext, libucontext_getcontext)
 
-FUNC(__getcontext)
+FUNC(libucontext_getcontext)
 	/* copy $gp, $sp, $fp to temporary registers so we don't clobber them */
 	move	$a2, $gp
 	move	$a3, $sp
 	move	$a4, $fp
 
-	PUSH_FRAME(__getcontext)
+	PUSH_FRAME(libucontext_getcontext)
 
 	/* set registers */
 	sd	$s0, REG_OFFSET(16)($a0)
@@ -40,7 +41,7 @@ FUNC(__getcontext)
 	sd	$ra, REG_OFFSET(31)($a0)
 	sd	$ra, (MCONTEXT_PC)($a0)
 
-	POP_FRAME(__getcontext)
+	POP_FRAME(libucontext_getcontext)
 
 	jr	$ra
-END(__getcontext)
+END(libucontext_getcontext)

arch/mips64/include/libucontext/bits.h

@@ -0,0 +1,47 @@
+#ifndef LIBUCONTEXT_BITS_H
+#define LIBUCONTEXT_BITS_H
+
+typedef unsigned long long libucontext_greg_t, libucontext_gregset_t[32];
+
+typedef struct {
+	union {
+		double fp_dregs[32];
+		struct {
+			float _fp_fregs;
+			unsigned _fp_pad;
+		} fp_fregs[32];
+	} fp_r;
+} libucontext_fpregset_t;
+
+typedef struct {
+	libucontext_gregset_t gregs;
+	libucontext_fpregset_t fpregs;
+	libucontext_greg_t mdhi;
+	libucontext_greg_t hi1;
+	libucontext_greg_t hi2;
+	libucontext_greg_t hi3;
+	libucontext_greg_t mdlo;
+	libucontext_greg_t lo1;
+	libucontext_greg_t lo2;
+	libucontext_greg_t lo3;
+	libucontext_greg_t pc;
+	unsigned int fpc_csr;
+	unsigned int used_math;
+	unsigned int dsp;
+	unsigned int reserved;
+} libucontext_mcontext_t;
+
+typedef struct {
+	void *ss_sp;
+	size_t ss_size;
+	int ss_flags;
+} libucontext_stack_t;
+
+typedef struct libucontext_ucontext {
+	unsigned long uc_flags;
+	struct libucontext_ucontext *uc_link;
+	libucontext_stack_t uc_stack;
+	libucontext_mcontext_t uc_mcontext;
+} libucontext_ucontext_t;
+
+#endif

arch/mips64/makecontext.S

@@ -26,10 +26,11 @@ A7_OFF = FRAMESZ - (1 * REG_SZ)
  * assembly rather than C.  Annoying, that...
  */
 
-ALIAS(makecontext, __makecontext)
+ALIAS(makecontext, libucontext_makecontext)
+ALIAS(__makecontext, libucontext_makecontext)
 
-FUNC(__makecontext)
-	PUSH_FRAME(__makecontext)
+FUNC(libucontext_makecontext)
+	PUSH_FRAME(libucontext_makecontext)
 
 	/* store $a3 through $a7 to the stack frame. */
 	sd	$a3, A3_OFF($sp)
@@ -82,7 +83,7 @@ store_stack_arg:
 
 no_more_arguments:
 	/* trampoline setup. */
-	dla	$t9, __start_context
+	dla	$t9, libucontext_trampoline
 
 	/* copy link pointer as $s0... */
 	ld	$v1, UCONTEXT_UC_LINK($a0)
@@ -100,7 +101,7 @@ no_more_arguments:
 	/* set our $pc */
 	sd	$a1, MCONTEXT_PC($a0)
 
-	POP_FRAME(__makecontext)
+	POP_FRAME(libucontext_makecontext)
 
 	jr	$ra
-END(__makecontext)
+END(libucontext_makecontext)

arch/mips64/setcontext.S

@@ -14,10 +14,11 @@ LOCALSZ = 1
 
 #include "defs.h"
 
-ALIAS(setcontext, __setcontext)
+ALIAS(setcontext, libucontext_setcontext)
+ALIAS(__setcontext, libucontext_setcontext)
 
-FUNC(__setcontext)
-	PUSH_FRAME(__setcontext)
+FUNC(libucontext_setcontext)
+	PUSH_FRAME(libucontext_setcontext)
 
 	/* move the context to $v0 */	
 	move	$v0, $a0
@@ -50,5 +51,5 @@ FUNC(__setcontext)
 	move	$v0, $zero
 	jr	$t9
 
-	POP_FRAME(__setcontext)
-END(__setcontext)
+	POP_FRAME(libucontext_setcontext)
+END(libucontext_setcontext)

arch/mips64/startcontext.S

@@ -14,7 +14,8 @@ LOCALSZ = 1
 
 #include "defs.h"
 
-FUNC(__start_context)
+.hidden libucontext_trampoline
+FUNC(libucontext_trampoline)
 	move	$gp, $s1
 
 	/* we receive our initial ucontext in $s0, so if $s0 is nil, bail */
@@ -22,7 +23,7 @@ FUNC(__start_context)
 
 	/* call setcontext */
 	move	$a0, $s0
-	dla	$t9, __setcontext
+	dla	$t9, PROC_NAME(libucontext_setcontext)
 
 	jr	$t9
 
@@ -31,4 +32,4 @@ no_linked_context:
 	dla	$t9, exit
 	jalr	$t9
 	nop
-END(__start_context)
+END(libucontext_trampoline)

arch/mips64/swapcontext.S

@@ -16,15 +16,16 @@ LOCALSZ = 2
 
 A1_OFFSET = FRAMESZ - (1 * REG_SZ)
 
-ALIAS(swapcontext, __swapcontext)
+ALIAS(swapcontext, libucontext_swapcontext)
+ALIAS(__swapcontext, libucontext_swapcontext)
 
-FUNC(__swapcontext)
+FUNC(libucontext_swapcontext)
 	/* copy $gp, $sp, $fp to temporary registers so we don't clobber them */
 	move	$a2, $gp
 	move	$a3, $sp
 	move	$a4, $fp
 
-	PUSH_FRAME(__swapcontext)
+	PUSH_FRAME(libucontext_swapcontext)
 
 	/* set registers */
 	sd	$s0, REG_OFFSET(16)($a0)
@@ -79,8 +80,8 @@ FUNC(__swapcontext)
 fail:
 	dla	$t9, exit
 
-	POP_FRAME(__swapcontext)
+	POP_FRAME(libucontext_swapcontext)
 
 	move	$v0, $zero
 	jalr	$t9
-END(__swapcontext)
+END(libucontext_swapcontext)

arch/or1k/defs.h

@@ -0,0 +1,22 @@
+#ifndef __ARCH_OR1K_DEFS_H
+#define __ARCH_OR1K_DEFS_H
+
+#define REG_SZ		(4)
+#define MCONTEXT_GREGS	(20)
+
+#define REG_SP		(1)
+#define REG_FP		(2)
+#define REG_RA		(9)
+#define REG_SA		(11)
+#define REG_LR		(14)
+#define REG_PC		(33)
+#define REG_SR		(34)
+
+#define PC_OFFSET	REG_OFFSET(REG_PC)
+
+#define FETCH_LINKPTR(dest) \
+	asm("l.ori %0, r14, 0" :: "r" ((dest)))
+
+#include "common-defs.h"
+
+#endif

arch/or1k/getcontext.S

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2022 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include "defs.h"
+
+ALIAS(getcontext, libucontext_getcontext)
+ALIAS(__getcontext, libucontext_getcontext)
+
+FUNC(libucontext_getcontext)
+	l.sw		REG_OFFSET(1)(r3), r1			/* store r1 and r2 */
+	l.sw		REG_OFFSET(2)(r3), r2
+
+	l.sw		REG_OFFSET(9)(r3), r9			/* store r9 to both r9 and r11 in the context */
+	l.sw		REG_OFFSET(11)(r3), r9
+
+	l.sw		REG_OFFSET(10)(r3), r10			/* store r10 for TLS */
+
+	l.sw		REG_OFFSET(14)(r3), r14			/* store r14 through r30 even */
+	l.sw		REG_OFFSET(16)(r3), r16
+	l.sw		REG_OFFSET(18)(r3), r18
+	l.sw		REG_OFFSET(20)(r3), r20
+	l.sw		REG_OFFSET(22)(r3), r22
+	l.sw		REG_OFFSET(24)(r3), r24
+	l.sw		REG_OFFSET(26)(r3), r26
+	l.sw		REG_OFFSET(28)(r3), r28
+	l.sw		REG_OFFSET(30)(r3), r30
+
+	l.jr		r9
+	l.ori		r11, r0, 0
+END(libucontext_getcontext)

arch/or1k/include/libucontext/bits.h

@@ -0,0 +1,28 @@
+#ifndef LIBUCONTEXT_BITS_H
+#define LIBUCONTEXT_BITS_H
+
+typedef struct sigaltstack {
+	void *ss_sp;
+	int ss_flags;
+	size_t ss_size;
+} libucontext_stack_t;
+
+typedef int libucontext_greg_t, libucontext_gregset_t[32];
+
+typedef struct {
+	struct {
+		libucontext_gregset_t gpr;
+		libucontext_greg_t pc;
+		libucontext_greg_t sr;
+	} regs;
+	unsigned long oldmask;
+} libucontext_mcontext_t;
+
+typedef struct libucontext_ucontext {
+	unsigned long uc_flags;
+	struct libucontext_ucontext *uc_link;
+	libucontext_stack_t uc_stack;
+	libucontext_mcontext_t uc_mcontext;
+} libucontext_ucontext_t;
+
+#endif

arch/or1k/makecontext.c

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2022 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include <stddef.h>
+#include <stdarg.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdio.h>
+#include "defs.h"
+#include <libucontext/libucontext.h>
+
+
+extern void libucontext_trampoline(void);
+
+
+void
+libucontext_makecontext(libucontext_ucontext_t *ucp, void (*func)(void), int argc, ...)
+{
+	libucontext_greg_t *sp;
+	va_list va;
+	int i;
+
+	/* set up and align the stack. */
+	sp = (libucontext_greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
+	sp -= argc < 6 ? 0 : (argc - 6);
+	sp = (libucontext_greg_t *) (((uintptr_t) sp & ~0x3));
+
+	/* set up the ucontext structure */
+	ucp->uc_mcontext.regs.gpr[REG_SP] = (libucontext_greg_t) sp;
+	ucp->uc_mcontext.regs.gpr[REG_RA] = (libucontext_greg_t) &libucontext_trampoline;
+	ucp->uc_mcontext.regs.gpr[REG_FP] = 0;
+	ucp->uc_mcontext.regs.gpr[REG_SA] = (libucontext_greg_t) func;
+	ucp->uc_mcontext.regs.gpr[REG_LR] = (libucontext_greg_t) ucp->uc_link;
+
+	va_start(va, argc);
+
+	/* args less than argv[6] have dedicated registers, else they overflow onto stack */
+	for (i = 0; i < argc; i++)
+	{
+		if (i < 6)
+			ucp->uc_mcontext.regs.gpr[i + 3] = va_arg (va, libucontext_greg_t);
+		else
+			sp[i - 6] = va_arg (va, libucontext_greg_t);
+	}
+
+	va_end(va);
+}
+
+#ifdef EXPORT_UNPREFIXED
+extern __typeof(libucontext_makecontext) makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+extern __typeof(libucontext_makecontext) __makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+#endif

arch/or1k/setcontext.S

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2022 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include "defs.h"
+
+ALIAS(setcontext, libucontext_setcontext)
+ALIAS(__setcontext, libucontext_setcontext)
+
+FUNC(libucontext_setcontext)
+	l.ori		r30, r3, 0				/* avoid clobbering r3 by copying to r30 */
+
+	l.lwz		r3, REG_OFFSET(3)(r30)			/* restore r3-r8 (argument registers) */
+	l.lwz		r4, REG_OFFSET(4)(r30)
+	l.lwz		r5, REG_OFFSET(5)(r30)
+	l.lwz		r6, REG_OFFSET(6)(r30)
+	l.lwz		r7, REG_OFFSET(7)(r30)
+	l.lwz		r8, REG_OFFSET(8)(r30)
+
+	l.lwz		r1, REG_OFFSET(1)(r30)			/* restore stack/frame pointers */
+	l.lwz		r2, REG_OFFSET(2)(r30)
+
+	l.lwz		r9, REG_OFFSET(9)(r30)			/* restore link register and starting address register */
+	l.lwz		r11, REG_OFFSET(11)(r30)
+
+	l.lwz		r10, REG_OFFSET(10)(r30)		/* restore TLS register */
+
+	l.lwz		r14, REG_OFFSET(14)(r30)		/* restore r14-r30, even only */
+	l.lwz		r16, REG_OFFSET(16)(r30)
+	l.lwz		r18, REG_OFFSET(18)(r30)
+	l.lwz		r20, REG_OFFSET(20)(r30)
+	l.lwz		r22, REG_OFFSET(22)(r30)
+	l.lwz		r24, REG_OFFSET(24)(r30)
+	l.lwz		r26, REG_OFFSET(26)(r30)
+	l.lwz		r28, REG_OFFSET(28)(r30)
+	l.lwz		r30, REG_OFFSET(30)(r30)
+
+	l.jr		r11					/* jump to new starting address */
+	l.ori		r11, r0, 0
+END(libucontext_setcontext)

arch/or1k/swapcontext.S

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2022 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include "defs.h"
+
+ALIAS(swapcontext, libucontext_swapcontext)
+ALIAS(__swapcontext, libucontext_swapcontext)
+
+FUNC(libucontext_swapcontext)
+	/* copy context into r3 like getcontext */
+	l.sw		REG_OFFSET(1)(r3), r1			/* store r1 and r2 */
+	l.sw		REG_OFFSET(2)(r3), r2
+
+	l.sw		REG_OFFSET(9)(r3), r9			/* store r9 to both r9 and r11 in the context */
+	l.sw		REG_OFFSET(11)(r3), r9
+
+	l.sw		REG_OFFSET(10)(r3), r10			/* store r10 for TLS */
+
+	l.sw		REG_OFFSET(14)(r3), r14			/* store r14 through r30 even */
+	l.sw		REG_OFFSET(16)(r3), r16
+	l.sw		REG_OFFSET(18)(r3), r18
+	l.sw		REG_OFFSET(20)(r3), r20
+	l.sw		REG_OFFSET(22)(r3), r22
+	l.sw		REG_OFFSET(24)(r3), r24
+	l.sw		REG_OFFSET(26)(r3), r26
+	l.sw		REG_OFFSET(28)(r3), r28
+	l.sw		REG_OFFSET(30)(r3), r30
+
+	/* set the new context from r4 */
+	l.ori		r30, r4, 0				/* copy r4 to r30 to avoid clobbering */
+
+	l.lwz		r3, REG_OFFSET(3)(r30)			/* restore r3-r8 (argument registers) */
+	l.lwz		r4, REG_OFFSET(4)(r30)
+	l.lwz		r5, REG_OFFSET(5)(r30)
+	l.lwz		r6, REG_OFFSET(6)(r30)
+	l.lwz		r7, REG_OFFSET(7)(r30)
+	l.lwz		r8, REG_OFFSET(8)(r30)
+
+	l.lwz		r1, REG_OFFSET(1)(r30)			/* restore stack/frame pointers */
+	l.lwz		r2, REG_OFFSET(2)(r30)
+
+	l.lwz		r9, REG_OFFSET(9)(r30)			/* restore link register and starting address register */
+	l.lwz		r11, REG_OFFSET(11)(r30)
+
+	l.lwz		r10, REG_OFFSET(10)(r30)		/* restore TLS register */
+
+	l.lwz		r14, REG_OFFSET(14)(r30)		/* restore r14-r30, even only */
+	l.lwz		r16, REG_OFFSET(16)(r30)
+	l.lwz		r18, REG_OFFSET(18)(r30)
+	l.lwz		r20, REG_OFFSET(20)(r30)
+	l.lwz		r22, REG_OFFSET(22)(r30)
+	l.lwz		r24, REG_OFFSET(24)(r30)
+	l.lwz		r26, REG_OFFSET(26)(r30)
+	l.lwz		r28, REG_OFFSET(28)(r30)
+	l.lwz		r30, REG_OFFSET(30)(r30)
+
+	l.jr		r11					/* jump to new starting address */
+	l.ori		r11, r0, 0
+END(libucontext_swapcontext)

arch/or1k/trampoline.c

@@ -0,0 +1,3 @@
+#include "defs.h"
+#include <libucontext/libucontext.h>
+#include "common-trampoline.c"

arch/ppc/defs.h

@@ -59,4 +59,6 @@
 /* lnk register is actually r32 */
 #define REG_LNK		REG_R36
 
+#include "common-defs.h"
+
 #endif

arch/ppc/getcontext.S

@@ -10,11 +10,13 @@
  * from the use of this software.
  */
 
-.global __getcontext
-.hidden __swapcontext
-__getcontext:
-	li 4, 0
-	b __swapcontext@local
+#include "common-defs.h"
 
-.weak getcontext
-getcontext = __getcontext
+ALIAS(getcontext, libucontext_getcontext)
+ALIAS(__getcontext, libucontext_getcontext)
+
+.hidden __libucontext_swapcontext
+FUNC(libucontext_getcontext)
+	li 4, 0
+	b __libucontext_swapcontext@local
+END(libucontext_getcontext)

arch/ppc/makecontext.c

@@ -11,34 +11,33 @@
  * from the use of this software.
  */
 
-#define _GNU_SOURCE
 #include <stdarg.h>
-#include <signal.h>
 #include <stdint.h>
 
 
 #include "defs.h"
+#include <libucontext/libucontext.h>
 
 
-extern void __start_context(void);
+extern void libucontext_trampoline(void);
 
 
 void
-__makecontext(ucontext_t *ucp, void (*func)(), int argc, ...)
+libucontext_makecontext(libucontext_ucontext_t *ucp, void (*func)(), int argc, ...)
 {
-	greg_t *sp;
+	libucontext_greg_t *sp;
 	va_list va;
 	int i;
 	unsigned int stack_args;
 
 	stack_args = argc > 8 ? argc - 8 : 0;
 
-	sp = (greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
+	sp = (libucontext_greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
 	sp -= stack_args + 2;
-	sp = (greg_t *) ((uintptr_t) sp & -16L);
+	sp = (libucontext_greg_t *) ((uintptr_t) sp & -16L);
 
 	ucp->uc_mcontext.gregs[REG_NIP]  = (uintptr_t) func;
-	ucp->uc_mcontext.gregs[REG_LNK]  = (uintptr_t) &__start_context;
+	ucp->uc_mcontext.gregs[REG_LNK]  = (uintptr_t) &libucontext_trampoline;
 	ucp->uc_mcontext.gregs[REG_R31]  = (uintptr_t) ucp->uc_link;
 	ucp->uc_mcontext.gregs[REG_SP]   = (uintptr_t) sp;
 
@@ -48,13 +47,15 @@ __makecontext(ucontext_t *ucp, void (*func)(), int argc, ...)
 
 	for (i = 0; i < argc; i++) {
 		if (i < 8)
-			ucp->uc_mcontext.gregs[i + 3] = va_arg (va, greg_t);
+			ucp->uc_mcontext.gregs[i + 3] = va_arg (va, libucontext_greg_t);
 		else
-			sp[i-8 + 2] = va_arg (va, greg_t);
+			sp[i-8 + 2] = va_arg (va, libucontext_greg_t);
 	}
 
 	va_end(va);
 }
 
-
-extern __typeof(__makecontext) makecontext __attribute__((weak, __alias__("__makecontext")));
+#ifdef EXPORT_UNPREFIXED
+extern __typeof(libucontext_makecontext) makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+extern __typeof(libucontext_makecontext) __makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+#endif

arch/ppc/setcontext.S

@@ -10,12 +10,14 @@
  * from the use of this software.
  */
 
-.global __setcontext
-.hidden __swapcontext
-__setcontext:
+#include "common-defs.h"
+
+ALIAS(setcontext, libucontext_setcontext)
+ALIAS(__setcontext, libucontext_setcontext)
+
+.hidden __libucontext_swapcontext
+FUNC(libucontext_setcontext)
 	mr 4, 3
 	li 3, 0
-	b __swapcontext@local
-
-.weak setcontext
-setcontext = __setcontext
+	b __libucontext_swapcontext@local
+END(libucontext_setcontext)

arch/ppc/startcontext.S

@@ -10,8 +10,10 @@
  * from the use of this software.
  */
 
-.globl __start_context;
-__start_context:
+#include "common-defs.h"
+
+.hidden libucontext_trampoline
+FUNC(libucontext_trampoline)
 	/* get the proper context into position and test for NULL */
 	mr.	3,31
 
@@ -19,7 +21,8 @@ __start_context:
 	beq	no_linked_context
 
 	/* jump to setcontext */
-	bl	__setcontext@local
+	bl	libucontext_setcontext@local
 
 no_linked_context:
 	b	exit@GOT
+END(libucontext_trampoline)

arch/ppc/swapcontext.S

@@ -10,14 +10,20 @@
  * from the use of this software.
  */
 
-.global __swapcontext
-__swapcontext:
+#include "common-defs.h"
+
+ALIAS(swapcontext, __libucontext_swapcontext)
+ALIAS(__swapcontext, __libucontext_swapcontext)
+
+/* make sure this is visible regardless of EXPORT_UNPREFIXED */
+.weak libucontext_swapcontext
+libucontext_swapcontext = __libucontext_swapcontext
+
+FUNC(__libucontext_swapcontext)
 	li 0, 249     # SYS_swapcontext
 	li 5, 1184    # sizeof(ucontext_t)
 	sc
 
 .hidden __retfromsyscall
 	b __retfromsyscall@local
-
-.weak swapcontext
-swapcontext = __swapcontext
+END(__libucontext_swapcontext)

arch/ppc64/defs.h

@@ -62,4 +62,6 @@
 /* lnk register is actually %r36 */
 #define REG_LNK		REG_R36
 
+#include "common-defs.h"
+
 #endif

arch/ppc64/getcontext.S

@@ -10,16 +10,18 @@
  * from the use of this software.
  */
 
-.global __getcontext
-.hidden __swapcontext
-__getcontext:
-	addis 2, 12, .TOC.-__getcontext@ha
-	addi  2, 12, .TOC.-__getcontext@l
+#include "common-defs.h"
 
-	.localentry __getcontext,.-__getcontext
+ALIAS(getcontext, libucontext_getcontext)
+ALIAS(__getcontext, libucontext_getcontext)
+
+.hidden __libucontext_swapcontext
+FUNC(libucontext_getcontext)
+	addis 2, 12, .TOC.-libucontext_getcontext@ha
+	addi  2, 12, .TOC.-libucontext_getcontext@l
+
+	.localentry libucontext_getcontext,.-libucontext_getcontext
 
 	li 4, 0
-	b __swapcontext
-
-.weak getcontext
-getcontext = __getcontext
+	b __libucontext_swapcontext
+END(libucontext_getcontext)

arch/ppc64/makecontext.c

@@ -11,34 +11,33 @@
  * from the use of this software.
  */
 
-#define _GNU_SOURCE
 #include <stdarg.h>
-#include <signal.h>
 #include <stdint.h>
 
 
 #include "defs.h"
+#include <libucontext/libucontext.h>
 
 
-extern void __start_context(void);
+extern void libucontext_trampoline(void);
 
 
 void
-__makecontext(ucontext_t *ucp, void (*func)(), int argc, ...)
+libucontext_makecontext(libucontext_ucontext_t *ucp, void (*func)(), int argc, ...)
 {
-	greg_t *sp;
+	libucontext_greg_t *sp;
 	va_list va;
 	int i;
 	unsigned int stack_args;
 
 	stack_args = argc > 8 ? argc : 0;
 
-	sp = (greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
+	sp = (libucontext_greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
 	sp -= stack_args + 4;
-	sp = (greg_t *) ((uintptr_t) sp & -16L);
+	sp = (libucontext_greg_t *) ((uintptr_t) sp & -16L);
 
 	ucp->uc_mcontext.gp_regs[REG_NIP]   = (uintptr_t) func;
-	ucp->uc_mcontext.gp_regs[REG_LNK]   = (uintptr_t) &__start_context;
+	ucp->uc_mcontext.gp_regs[REG_LNK]   = (uintptr_t) &libucontext_trampoline;
 	ucp->uc_mcontext.gp_regs[REG_SP]    = (uintptr_t) sp;
 	ucp->uc_mcontext.gp_regs[REG_ENTRY] = (uintptr_t) func;
 	ucp->uc_mcontext.gp_regs[REG_R31]   = (uintptr_t) ucp->uc_link;
@@ -49,13 +48,15 @@ __makecontext(ucontext_t *ucp, void (*func)(), int argc, ...)
 
 	for (i = 0; i < argc; i++) {
 		if (i < 8)
-			ucp->uc_mcontext.gp_regs[i + 3] = va_arg (va, greg_t);
+			ucp->uc_mcontext.gp_regs[i + 3] = va_arg (va, libucontext_greg_t);
 		else
-			sp[i + 4] = va_arg (va, greg_t);
+			sp[i + 4] = va_arg (va, libucontext_greg_t);
 	}
 
 	va_end(va);
 }
 
-
-extern __typeof(__makecontext) makecontext __attribute__((weak, __alias__("__makecontext")));
+#ifdef EXPORT_UNPREFIXED
+extern __typeof(libucontext_makecontext) makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+extern __typeof(libucontext_makecontext) __makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+#endif

arch/ppc64/setcontext.S

@@ -10,17 +10,19 @@
  * from the use of this software.
  */
 
-.global __setcontext
-.hidden __swapcontext
-__setcontext:
-	addis 2, 12, .TOC.-__setcontext@ha
-	addi  2, 12, .TOC.-__setcontext@l
+#include "common-defs.h"
 
-	.localentry __setcontext,.-__setcontext
+ALIAS(setcontext, libucontext_setcontext)
+ALIAS(__setcontext, libucontext_setcontext)
+
+.hidden __libucontext_swapcontext
+FUNC(libucontext_setcontext)
+	addis 2, 12, .TOC.-libucontext_setcontext@ha
+	addi  2, 12, .TOC.-libucontext_setcontext@l
+
+	.localentry libucontext_setcontext,.-libucontext_setcontext
 
 	mr 4, 3
 	li 3, 0
-	b __swapcontext
-
-.weak setcontext
-setcontext = __setcontext
+	b __libucontext_swapcontext
+END(libucontext_setcontext)

arch/ppc64/startcontext.S

@@ -10,9 +10,10 @@
  * from the use of this software.
  */
 
-.globl __start_context;
-.hidden __start_context;
-__start_context:
+#include "common-defs.h"
+
+.hidden libucontext_trampoline
+FUNC(libucontext_trampoline)
 	cmpdi	31,0			/* test if ucontext link pointer is null */
 	beq	no_linked_context	/* if it is, exit */
 
@@ -29,3 +30,4 @@ __start_context:
 no_linked_context:
 	b	exit@GOT
 	nop
+END(libucontext_trampoline)

arch/ppc64/swapcontext.S

@@ -10,12 +10,20 @@
  * from the use of this software.
  */
 
-.global __swapcontext
-__swapcontext:
-	addis 2, 12, .TOC.-__swapcontext@ha
-	addi  2, 12, .TOC.-__swapcontext@l
+#include "common-defs.h"
 
-	.localentry __swapcontext,.-__swapcontext
+ALIAS(swapcontext, __libucontext_swapcontext)
+ALIAS(__swapcontext, __libucontext_swapcontext)
+
+/* make sure this is visible regardless of EXPORT_UNPREFIXED */
+.weak libucontext_swapcontext
+libucontext_swapcontext = __libucontext_swapcontext
+
+FUNC(__libucontext_swapcontext)
+	addis 2, 12, .TOC.-__libucontext_swapcontext@ha
+	addi  2, 12, .TOC.-__libucontext_swapcontext@l
+
+	.localentry __libucontext_swapcontext,.-__libucontext_swapcontext
 
 	li 0, 249     # SYS_swapcontext
 	li 5, 1696    # sizeof(ucontext_t)
@@ -23,6 +31,4 @@ __swapcontext:
 
 .hidden __retfromsyscall
 	b __retfromsyscall
-
-.weak swapcontext
-swapcontext = __swapcontext
+END(__libucontext_swapcontext)

arch/riscv32/defs.h

@@ -0,0 +1,55 @@
+#ifndef __ARCH_RISCV64_DEFS_H
+#define __ARCH_RISCV64_DEFS_H
+
+#define REG_SZ		(4)
+#define MCONTEXT_GREGS	(160)
+
+/* program counter is saved in x0 as well as x1, similar to mips */
+#ifndef REG_PC
+#define REG_PC		(0)
+#endif
+
+#ifndef REG_RA
+#define REG_RA		(1)
+#endif
+
+#ifndef REG_SP
+#define REG_SP		(2)
+#endif
+
+#ifndef REG_S0
+#define REG_S0		(8)
+#endif
+
+#define REG_S1		(9)
+
+#ifndef REG_A0
+#define REG_A0		(10)
+#endif
+
+#define REG_A1		(11)
+#define REG_A2		(12)
+#define REG_A3		(13)
+#define REG_A4		(14)
+#define REG_A5		(15)
+#define REG_A6		(16)
+#define REG_A7		(17)
+#define REG_S2		(18)
+#define REG_S3		(19)
+#define REG_S4		(20)
+#define REG_S5		(21)
+#define REG_S6		(22)
+#define REG_S7		(23)
+#define REG_S8		(24)
+#define REG_S9		(25)
+#define REG_S10		(26)
+#define REG_S11		(27)
+
+#define PC_OFFSET	REG_OFFSET(REG_PC)
+
+#define FETCH_LINKPTR(dest) \
+	asm("mv	%0, s1" : "=r" ((dest)))
+
+#include "common-defs.h"
+
+#endif

arch/riscv32/getcontext.S

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include "defs.h"
+
+ALIAS(getcontext, libucontext_getcontext)
+ALIAS(__getcontext, libucontext_getcontext)
+
+FUNC(libucontext_getcontext)
+	sw ra, REG_OFFSET(REG_PC)(a0)
+	sw ra, REG_OFFSET(REG_RA)(a0)
+	sw sp, REG_OFFSET(REG_SP)(a0)
+
+	/* first saved register block */
+	sw s0, REG_OFFSET(REG_S0)(a0)
+	sw s1, REG_OFFSET(REG_S1)(a0)
+
+	/* return register block */
+	sw a0, REG_OFFSET(REG_A0)(a0)
+	sw a1, REG_OFFSET(REG_A1)(a0)
+
+	/* second saved register block */
+	sw s2, REG_OFFSET(REG_S2)(a0)
+	sw s3, REG_OFFSET(REG_S3)(a0)
+	sw s4, REG_OFFSET(REG_S4)(a0)
+	sw s5, REG_OFFSET(REG_S5)(a0)
+	sw s6, REG_OFFSET(REG_S6)(a0)
+	sw s7, REG_OFFSET(REG_S7)(a0)
+	sw s8, REG_OFFSET(REG_S8)(a0)
+	sw s9, REG_OFFSET(REG_S9)(a0)
+	sw s10, REG_OFFSET(REG_S10)(a0)
+	sw s11, REG_OFFSET(REG_S11)(a0)
+
+	/* done saving, return */
+	ret
+END(libucontext_getcontext)

arch/riscv32/include/libucontext/bits.h

@@ -0,0 +1,48 @@
+#ifndef LIBUCONTEXT_BITS_H
+#define LIBUCONTEXT_BITS_H
+
+typedef unsigned long libucontext_greg_t;
+typedef unsigned long libucontext__riscv_mc_gp_state[32];
+
+struct libucontext__riscv_mc_f_ext_state {
+	unsigned int __f[32];
+	unsigned int __fcsr;
+};
+
+struct libucontext__riscv_mc_d_ext_state {
+	unsigned long long __f[32];
+	unsigned int __fcsr;
+};
+
+struct libucontext__riscv_mc_q_ext_state {
+	unsigned long long __f[64] __attribute__((aligned(16)));
+	unsigned int __fcsr;
+	unsigned int __reserved[3];
+};
+
+union libucontext__riscv_mc_fp_state {
+	struct libucontext__riscv_mc_f_ext_state __f;
+	struct libucontext__riscv_mc_d_ext_state __d;
+	struct libucontext__riscv_mc_q_ext_state __q;
+};
+
+typedef struct libucontext_mcontext {
+	libucontext__riscv_mc_gp_state __gregs;
+	union libucontext__riscv_mc_fp_state __fpregs;
+} libucontext_mcontext_t;
+
+typedef struct {
+	void *ss_sp;
+	int ss_flags;
+	size_t ss_size;
+} libucontext_stack_t;
+
+typedef struct libucontext_ucontext {
+	unsigned long uc_flags;
+	struct libucontext_ucontext *uc_link;
+	libucontext_stack_t uc_stack;
+	unsigned char __pad[128];
+	libucontext_mcontext_t uc_mcontext;
+} libucontext_ucontext_t;
+
+#endif

arch/riscv32/makecontext.c

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2018 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include <stddef.h>
+#include <stdarg.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdio.h>
+#include "defs.h"
+#include <libucontext/libucontext.h>
+
+
+extern void libucontext_trampoline(void);
+
+
+void
+libucontext_makecontext(libucontext_ucontext_t *ucp, void (*func)(void), int argc, ...)
+{
+	libucontext_greg_t *sp, *regp;
+	va_list va;
+	int i;
+
+	/* set up and align the stack. */
+	sp = (libucontext_greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
+	sp -= argc < 8 ? 0 : argc - 8;
+	sp = (libucontext_greg_t *) (((uintptr_t) sp & -16L));
+
+	/* set up the ucontext structure */
+	ucp->uc_mcontext.__gregs[REG_RA] = (libucontext_greg_t) libucontext_trampoline;
+	ucp->uc_mcontext.__gregs[REG_S0] = 0;
+	ucp->uc_mcontext.__gregs[REG_S1] = (libucontext_greg_t) ucp->uc_link;
+	ucp->uc_mcontext.__gregs[REG_SP] = (libucontext_greg_t) sp;
+	ucp->uc_mcontext.__gregs[REG_PC] = (libucontext_greg_t) func;
+
+	va_start(va, argc);
+
+	/* first 8 args go in $a0 through $a7. */
+	regp = &(ucp->uc_mcontext.__gregs[REG_A0]);
+
+	for (i = 0; (i < argc && i < 8); i++)
+		*regp++ = va_arg (va, libucontext_greg_t);
+
+	/* remainder overflows into stack */
+	for (; i < argc; i++)
+		*sp++ = va_arg (va, libucontext_greg_t);
+
+	va_end(va);
+}
+
+#ifdef EXPORT_UNPREFIXED
+extern __typeof(libucontext_makecontext) makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+extern __typeof(libucontext_makecontext) __makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+#endif

arch/riscv32/setcontext.S

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include "defs.h"
+
+ALIAS(setcontext, libucontext_setcontext)
+ALIAS(__setcontext, libucontext_setcontext)
+
+FUNC(libucontext_setcontext)
+	/* move $a0 to $t0 to avoid clobbering. */
+	mv t0, a0
+
+	lw t1, PC_OFFSET(t0)
+	lw ra, REG_OFFSET(REG_RA)(t0)
+	lw sp, REG_OFFSET(REG_SP)(t0)
+
+	/* first saved register block */
+	lw s0, REG_OFFSET(REG_S0)(t0)
+	lw s1, REG_OFFSET(REG_S1)(t0)
+
+	/* return register block */
+	lw a0, REG_OFFSET(REG_A0)(t0)
+	lw a1, REG_OFFSET(REG_A1)(t0)
+
+	/* argument register block */
+	lw a2, REG_OFFSET(REG_A2)(t0)
+	lw a3, REG_OFFSET(REG_A3)(t0)
+	lw a4, REG_OFFSET(REG_A4)(t0)
+	lw a5, REG_OFFSET(REG_A5)(t0)
+	lw a6, REG_OFFSET(REG_A6)(t0)
+	lw a7, REG_OFFSET(REG_A7)(t0)
+
+	/* second saved register block */
+	lw s2, REG_OFFSET(REG_S2)(t0)
+	lw s3, REG_OFFSET(REG_S3)(t0)
+	lw s4, REG_OFFSET(REG_S4)(t0)
+	lw s5, REG_OFFSET(REG_S5)(t0)
+	lw s6, REG_OFFSET(REG_S6)(t0)
+	lw s7, REG_OFFSET(REG_S7)(t0)
+	lw s8, REG_OFFSET(REG_S8)(t0)
+	lw s9, REG_OFFSET(REG_S9)(t0)
+	lw s10, REG_OFFSET(REG_S10)(t0)
+	lw s11, REG_OFFSET(REG_S11)(t0)
+
+	/* done restoring, jump to new pc in S1 */
+	jr t1
+END(libucontext_setcontext)

arch/riscv32/swapcontext.S

@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include "defs.h"
+
+ALIAS(swapcontext, libucontext_swapcontext)
+ALIAS(__swapcontext, libucontext_swapcontext)
+
+FUNC(libucontext_swapcontext)
+	/* move $a1 to $t0 to avoid clobbering. */
+	mv t0, a1
+
+	sw ra, REG_OFFSET(REG_PC)(a0)
+	sw ra, REG_OFFSET(REG_RA)(a0)
+	sw sp, REG_OFFSET(REG_SP)(a0)
+
+	/* first saved register block */
+	sw s0, REG_OFFSET(REG_S0)(a0)
+	sw s1, REG_OFFSET(REG_S1)(a0)
+
+	/* return register block */
+	sw a0, REG_OFFSET(REG_A0)(a0)
+	sw a1, REG_OFFSET(REG_A1)(a0)
+
+	/* second saved register block */
+	sw s2, REG_OFFSET(REG_S2)(a0)
+	sw s3, REG_OFFSET(REG_S3)(a0)
+	sw s4, REG_OFFSET(REG_S4)(a0)
+	sw s5, REG_OFFSET(REG_S5)(a0)
+	sw s6, REG_OFFSET(REG_S6)(a0)
+	sw s7, REG_OFFSET(REG_S7)(a0)
+	sw s8, REG_OFFSET(REG_S8)(a0)
+	sw s9, REG_OFFSET(REG_S9)(a0)
+	sw s10, REG_OFFSET(REG_S10)(a0)
+	sw s11, REG_OFFSET(REG_S11)(a0)
+
+	/* restore the other context from $t0. */
+	lw t1, REG_OFFSET(REG_PC)(t0)
+	lw ra, REG_OFFSET(REG_RA)(t0)
+	lw sp, REG_OFFSET(REG_SP)(t0)
+
+	/* first saved register block */
+	lw s0, REG_OFFSET(REG_S0)(t0)
+	lw s1, REG_OFFSET(REG_S1)(t0)
+
+	/* return register block */
+	lw a0, REG_OFFSET(REG_A0)(t0)
+	lw a1, REG_OFFSET(REG_A1)(t0)
+
+	/* argument register block */
+	lw a2, REG_OFFSET(REG_A2)(t0)
+	lw a3, REG_OFFSET(REG_A3)(t0)
+	lw a4, REG_OFFSET(REG_A4)(t0)
+	lw a5, REG_OFFSET(REG_A5)(t0)
+	lw a6, REG_OFFSET(REG_A6)(t0)
+	lw a7, REG_OFFSET(REG_A7)(t0)
+
+	/* second saved register block */
+	lw s2, REG_OFFSET(REG_S2)(t0)
+	lw s3, REG_OFFSET(REG_S3)(t0)
+	lw s4, REG_OFFSET(REG_S4)(t0)
+	lw s5, REG_OFFSET(REG_S5)(t0)
+	lw s6, REG_OFFSET(REG_S6)(t0)
+	lw s7, REG_OFFSET(REG_S7)(t0)
+	lw s8, REG_OFFSET(REG_S8)(t0)
+	lw s9, REG_OFFSET(REG_S9)(t0)
+	lw s10, REG_OFFSET(REG_S10)(t0)
+	lw s11, REG_OFFSET(REG_S11)(t0)
+
+	/* done swapping, jump to new PC in S1 */
+	jr t1
+END(libucontext_swapcontext)

arch/riscv32/trampoline.c

@@ -0,0 +1,3 @@
+#include "defs.h"
+#include <libucontext/libucontext.h>
+#include "common-trampoline.c"

arch/riscv64/defs.h

@@ -5,12 +5,28 @@
 #define MCONTEXT_GREGS	(176)
 
 /* program counter is saved in x0 as well as x1, similar to mips */
-#define REG_PC_SAVE	(0)
-#define REG_PC		(1)
+#ifndef REG_PC
+#define REG_PC		(0)
+#endif
+
+#ifndef REG_RA
+#define REG_RA		(1)
+#endif
+
+#ifndef REG_SP
 #define REG_SP		(2)
+#endif
+
+#ifndef REG_S0
 #define REG_S0		(8)
+#endif
+
 #define REG_S1		(9)
+
+#ifndef REG_A0
 #define REG_A0		(10)
+#endif
+
 #define REG_A1		(11)
 #define REG_A2		(12)
 #define REG_A3		(13)
@@ -29,7 +45,10 @@
 #define REG_S10		(26)
 #define REG_S11		(27)
 
-#define PC_OFFSET	REG_OFFSET(REG_PC_SAVE)
+#define PC_OFFSET	REG_OFFSET(REG_PC)
+
+#define FETCH_LINKPTR(dest) \
+	asm("mv	%0, s1" : "=r" ((dest)))
 
 #include "common-defs.h"
 

arch/riscv64/getcontext.S

@@ -12,11 +12,12 @@
 
 #include "defs.h"
 
-ALIAS(getcontext, __getcontext)
+ALIAS(getcontext, libucontext_getcontext)
+ALIAS(__getcontext, libucontext_getcontext)
 
-FUNC(__getcontext)
-	sd ra, PC_OFFSET(a0)
+FUNC(libucontext_getcontext)
 	sd ra, REG_OFFSET(REG_PC)(a0)
+	sd ra, REG_OFFSET(REG_RA)(a0)
 	sd sp, REG_OFFSET(REG_SP)(a0)
 
 	/* first saved register block */
@@ -41,4 +42,4 @@ FUNC(__getcontext)
 
 	/* done saving, return */
 	ret
-END(__getcontext)
+END(libucontext_getcontext)

arch/riscv64/include/libucontext/bits.h

@@ -0,0 +1,48 @@
+#ifndef LIBUCONTEXT_BITS_H
+#define LIBUCONTEXT_BITS_H
+
+typedef unsigned long libucontext_greg_t;
+typedef unsigned long libucontext__riscv_mc_gp_state[32];
+
+struct libucontext__riscv_mc_f_ext_state {
+	unsigned int __f[32];
+	unsigned int __fcsr;
+};
+
+struct libucontext__riscv_mc_d_ext_state {
+	unsigned long long __f[32];
+	unsigned int __fcsr;
+};
+
+struct libucontext__riscv_mc_q_ext_state {
+	unsigned long long __f[64] __attribute__((aligned(16)));
+	unsigned int __fcsr;
+	unsigned int __reserved[3];
+};
+
+union libucontext__riscv_mc_fp_state {
+	struct libucontext__riscv_mc_f_ext_state __f;
+	struct libucontext__riscv_mc_d_ext_state __d;
+	struct libucontext__riscv_mc_q_ext_state __q;
+};
+
+typedef struct libucontext_mcontext {
+	libucontext__riscv_mc_gp_state __gregs;
+	union libucontext__riscv_mc_fp_state __fpregs;
+} libucontext_mcontext_t;
+
+typedef struct {
+	void *ss_sp;
+	int ss_flags;
+	size_t ss_size;
+} libucontext_stack_t;
+
+typedef struct libucontext_ucontext {
+	unsigned long uc_flags;
+	struct libucontext_ucontext *uc_link;
+	libucontext_stack_t uc_stack;
+	unsigned char __pad[128];
+	libucontext_mcontext_t uc_mcontext;
+} libucontext_ucontext_t;
+
+#endif

arch/riscv64/makecontext.c

@@ -10,38 +10,36 @@
  * from the use of this software.
  */
 
-#define _GNU_SOURCE
 #include <stddef.h>
 #include <stdarg.h>
-#include <signal.h>
 #include <string.h>
 #include <stdint.h>
 #include <stdio.h>
 #include "defs.h"
+#include <libucontext/libucontext.h>
 
 
-extern void __start_context(void);
+extern void libucontext_trampoline(void);
 
 
 void
-__makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
+libucontext_makecontext(libucontext_ucontext_t *ucp, void (*func)(void), int argc, ...)
 {
-	greg_t *sp, *regp;
+	libucontext_greg_t *sp, *regp;
 	va_list va;
 	int i;
 
 	/* set up and align the stack. */
-	sp = (greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
+	sp = (libucontext_greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
 	sp -= argc < 8 ? 0 : argc - 8;
-	sp = (greg_t *) (((uintptr_t) sp & -16L));
+	sp = (libucontext_greg_t *) (((uintptr_t) sp & -16L));
 
 	/* set up the ucontext structure */
-	ucp->uc_mcontext.__gregs[REG_PC] = (greg_t) __start_context;
+	ucp->uc_mcontext.__gregs[REG_RA] = (libucontext_greg_t) libucontext_trampoline;
 	ucp->uc_mcontext.__gregs[REG_S0] = 0;
-	ucp->uc_mcontext.__gregs[REG_S1] = (greg_t) func;
-	ucp->uc_mcontext.__gregs[REG_S2] = (greg_t) ucp->uc_link;
-	ucp->uc_mcontext.__gregs[REG_SP] = (greg_t) sp;
-	ucp->uc_mcontext.__gregs[REG_PC_SAVE] = 0;
+	ucp->uc_mcontext.__gregs[REG_S1] = (libucontext_greg_t) ucp->uc_link;
+	ucp->uc_mcontext.__gregs[REG_SP] = (libucontext_greg_t) sp;
+	ucp->uc_mcontext.__gregs[REG_PC] = (libucontext_greg_t) func;
 
 	va_start(va, argc);
 
@@ -49,14 +47,16 @@ __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
 	regp = &(ucp->uc_mcontext.__gregs[REG_A0]);
 
 	for (i = 0; (i < argc && i < 8); i++)
-		*regp++ = va_arg (va, greg_t);
+		*regp++ = va_arg (va, libucontext_greg_t);
 
 	/* remainder overflows into stack */
 	for (; i < argc; i++)
-		*sp++ = va_arg (va, greg_t);
+		*sp++ = va_arg (va, libucontext_greg_t);
 
 	va_end(va);
 }
 
-
-extern __typeof(__makecontext) makecontext __attribute__((weak, __alias__("__makecontext")));
+#ifdef EXPORT_UNPREFIXED
+extern __typeof(libucontext_makecontext) makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+extern __typeof(libucontext_makecontext) __makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+#endif

arch/riscv64/setcontext.S

@@ -12,14 +12,15 @@
 
 #include "defs.h"
 
-ALIAS(setcontext, __setcontext)
+ALIAS(setcontext, libucontext_setcontext)
+ALIAS(__setcontext, libucontext_setcontext)
 
-FUNC(__setcontext)
+FUNC(libucontext_setcontext)
 	/* move $a0 to $t0 to avoid clobbering. */
 	mv t0, a0
 
 	ld t1, PC_OFFSET(t0)
-	ld ra, REG_OFFSET(REG_PC)(t0)
+	ld ra, REG_OFFSET(REG_RA)(t0)
 	ld sp, REG_OFFSET(REG_SP)(t0)
 
 	/* first saved register block */
@@ -50,6 +51,6 @@ FUNC(__setcontext)
 	ld s10, REG_OFFSET(REG_S10)(t0)
 	ld s11, REG_OFFSET(REG_S11)(t0)
 
-	/* done saving, return */
-	ret
-END(__setcontext)
+	/* done restoring, jump to new pc in S1 */
+	jr t1
+END(libucontext_setcontext)

arch/riscv64/swapcontext.S

@@ -12,14 +12,15 @@
 
 #include "defs.h"
 
-ALIAS(swapcontext, __swapcontext)
+ALIAS(swapcontext, libucontext_swapcontext)
+ALIAS(__swapcontext, libucontext_swapcontext)
 
-FUNC(__swapcontext)
+FUNC(libucontext_swapcontext)
 	/* move $a1 to $t0 to avoid clobbering. */
 	mv t0, a1
 
-	sd ra, PC_OFFSET(a0)
 	sd ra, REG_OFFSET(REG_PC)(a0)
+	sd ra, REG_OFFSET(REG_RA)(a0)
 	sd sp, REG_OFFSET(REG_SP)(a0)
 
 	/* first saved register block */
@@ -43,8 +44,8 @@ FUNC(__swapcontext)
 	sd s11, REG_OFFSET(REG_S11)(a0)
 
 	/* restore the other context from $t0. */
-	ld t1, PC_OFFSET(t0)
-	ld ra, REG_OFFSET(REG_PC)(t0)
+	ld t1, REG_OFFSET(REG_PC)(t0)
+	ld ra, REG_OFFSET(REG_RA)(t0)
 	ld sp, REG_OFFSET(REG_SP)(t0)
 
 	/* first saved register block */
@@ -75,6 +76,6 @@ FUNC(__swapcontext)
 	ld s10, REG_OFFSET(REG_S10)(t0)
 	ld s11, REG_OFFSET(REG_S11)(t0)
 
-	/* done swapping, return */
-	ret
-END(__swapcontext)
+	/* done swapping, jump to new PC in S1 */
+	jr t1
+END(libucontext_swapcontext)

arch/riscv64/trampoline.c

@@ -0,0 +1,3 @@
+#include "defs.h"
+#include <libucontext/libucontext.h>
+#include "common-trampoline.c"

arch/s390x/getcontext.S

@@ -12,9 +12,10 @@
 
 #include "defs.h"
 
-ALIAS(getcontext, __getcontext)
+ALIAS(getcontext, libucontext_getcontext)
+ALIAS(__getcontext, libucontext_getcontext)
 
-FUNC(__getcontext)
+FUNC(libucontext_getcontext)
 	lgr	%r1, %r2			/* use %r1 as our working register */
 	la	%r2, 0				/* we will return 0 */
 
@@ -22,4 +23,4 @@ FUNC(__getcontext)
 	stmg	%r0, %r15, REG_OFFSET(0)(%r1)	/* store general-purpose registers */
 
 	br	%r14				/* return to where we came from */
-END(__getcontext)
+END(libucontext_getcontext)

arch/s390x/include/libucontext/bits.h

@@ -0,0 +1,41 @@
+#ifndef LIBUCONTEXT_BITS_H
+#define LIBUCONTEXT_BITS_H
+
+typedef unsigned long libucontext_greg_t, libucontext_gregset_t[27];
+
+typedef struct {
+	unsigned long mask;
+	unsigned long addr;
+} libucontext_psw_t;
+
+typedef union {
+	double d;
+	float f;
+} libucontext_fpreg_t;
+
+typedef struct {
+	unsigned fpc;
+	libucontext_fpreg_t fprs[16];
+} libucontext_fpregset_t;
+
+typedef struct {
+	libucontext_psw_t psw;
+	unsigned long gregs[16];
+	unsigned aregs[16];
+	libucontext_fpregset_t fpregs;
+} libucontext_mcontext_t;
+
+typedef struct {
+	void *ss_sp;
+	int ss_flags;
+	size_t ss_size;
+} libucontext_stack_t;
+
+typedef struct libucontext_ucontext {
+	unsigned long uc_flags;
+	struct libucontext_ucontext *uc_link;
+	libucontext_stack_t uc_stack;
+	libucontext_mcontext_t uc_mcontext;
+} libucontext_ucontext_t;
+
+#endif

arch/s390x/makecontext.c

@@ -10,47 +10,46 @@
  * from the use of this software.
  */
 
-#define _GNU_SOURCE
 #include <stddef.h>
 #include <stdarg.h>
-#include <signal.h>
 #include <string.h>
 #include <stdint.h>
 
 
 #include "defs.h"
+#include <libucontext/libucontext.h>
 
 
-extern void __start_context(void);
-extern int __setcontext(const ucontext_t *ucp);
+extern void libucontext_trampoline(void);
+extern int libucontext_setcontext(const libucontext_ucontext_t *ucp);
 
 
 void
-__makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
+libucontext_makecontext(libucontext_ucontext_t *ucp, void (*func)(void), int argc, ...)
 {
-	greg_t *sp;
+	libucontext_greg_t *sp;
 	va_list va;
 	int i;
 
-	sp = (greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
-	sp = (greg_t *) (((uintptr_t) sp & -8L));
+	sp = (libucontext_greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
+	sp = (libucontext_greg_t *) (((uintptr_t) sp & -8L));
 
 	ucp->uc_mcontext.gregs[7]  = (uintptr_t) func;
 	ucp->uc_mcontext.gregs[8]  = (uintptr_t) ucp->uc_link;
-	ucp->uc_mcontext.gregs[9]  = (uintptr_t) &__setcontext;
-	ucp->uc_mcontext.gregs[14] = (uintptr_t) &__start_context;
+	ucp->uc_mcontext.gregs[9]  = (uintptr_t) &libucontext_setcontext;
+	ucp->uc_mcontext.gregs[14] = (uintptr_t) &libucontext_trampoline;
 
 	va_start(va, argc);
 
 	for (i = 0; i < argc && i < 5; i++)
-		ucp->uc_mcontext.gregs[i + 2] = va_arg (va, greg_t);
+		ucp->uc_mcontext.gregs[i + 2] = va_arg (va, libucontext_greg_t);
 
 	if (argc > 5)
 	{
 		sp -= argc - 5;
 
 		for (i = 5; i < argc; i++)
-			sp[i - 5] = va_arg (va, greg_t);
+			sp[i - 5] = va_arg (va, libucontext_greg_t);
 	}
 
 	va_end(va);
@@ -63,5 +62,7 @@ __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
 	ucp->uc_mcontext.gregs[15] = (uintptr_t) sp;
 }
 
-
-extern __typeof(__makecontext) makecontext __attribute__((weak, __alias__("__makecontext")));
+#ifdef EXPORT_UNPREFIXED
+extern __typeof(libucontext_makecontext) makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+extern __typeof(libucontext_makecontext) __makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+#endif

arch/s390x/setcontext.S

@@ -12,13 +12,14 @@
 
 #include "defs.h"
 
-ALIAS(setcontext, __setcontext)
+ALIAS(setcontext, libucontext_setcontext)
+ALIAS(__setcontext, libucontext_setcontext)
 
-FUNC(__setcontext)
+FUNC(libucontext_setcontext)
 	lgr	%r1, %r2			/* use %r1 as our working register */
 
 	lam	%a2, %a15, AREG_OFFSET(2)(%r1)	/* load access registers, but skip %a0 and %a1 which are for TLS */
 	lmg	%r0, %r15, REG_OFFSET(0)(%r1)	/* store general-purpose registers */
 
 	br	%r14				/* return to new link register address */
-END(__setcontext)
+END(libucontext_setcontext)

arch/s390x/startcontext.S

@@ -12,7 +12,8 @@
 
 #include "defs.h"
 
-FUNC(__start_context)
+.hidden libucontext_trampoline
+FUNC(libucontext_trampoline)
 	basr	%r14, %r7			/* run function pointer (%r7) and return here */
 	ltgr	%r8, %r8			/* check to see if uc_link (%r8) is null */
 
@@ -26,4 +27,4 @@ no_linked_context:
 	brasl	%r14, exit@plt			/* call exit */
 
 	j	.+2				/* crash if exit returns */
-END(__start_context)
+END(libucontext_trampoline)

arch/s390x/swapcontext.S

@@ -12,9 +12,10 @@
 
 #include "defs.h"
 
-ALIAS(swapcontext, __swapcontext)
+ALIAS(swapcontext, libucontext_swapcontext)
+ALIAS(__swapcontext, libucontext_swapcontext)
 
-FUNC(__swapcontext)
+FUNC(libucontext_swapcontext)
 	lgr	%r1, %r2			/* use %r1 to save current context to */
 	lgr	%r0, %r3			/* use %r0 for source context */
 
@@ -26,4 +27,4 @@ FUNC(__swapcontext)
 	lmg	%r0, %r15, REG_OFFSET(0)(%r2)	/* load general-purpose registers */
 
 	br	%r14				/* return to new link register address */
-END(__swapcontext)
+END(libucontext_swapcontext)

arch/sh/defs.h

@@ -0,0 +1,20 @@
+#ifndef __ARCH_SH4_DEFS_H
+#define __ARCH_SH4_DEFS_H
+
+#define REG_SZ			(4)
+#define MCONTEXT_GREGS		(24)
+
+#define REG_SP			(15)
+#define REG_PC			(16)
+#define REG_PR			(17)
+#define REG_SR			(18)
+#define REG_GBR			(19)
+#define REG_MACH		(20)
+#define REG_MACL		(21)
+
+#define FETCH_LINKPTR(dest)	\
+	asm("mov r8, %0" : "=r" (dest));
+
+#include "common-defs.h"
+
+#endif

arch/sh/getcontext.S

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include "defs.h"
+
+ALIAS(getcontext, libucontext_getcontext)
+ALIAS(__getcontext, libucontext_getcontext)
+
+FUNC(libucontext_getcontext)
+	mov	r4, r0						/* move r4 to r0, and increment by REG_OFFSET(REG_MACL) + REG_SZ. */
+	add	#(REG_OFFSET(REG_MACL + 1)), r0
+
+	sts.l	macl, @-r0					/* save macl/mach registers */
+	sts.l	mach, @-r0
+
+	stc.l	gbr, @-r0					/* save gbr register */
+
+	movt	r1						/* load T-flag into r1 */
+	mov.l	r1, @-r0					/* save T-flag as SR register */
+
+	sts.l	pr, @-r0					/* save current PR */
+	sts.l	pr, @-r0					/* save current PR as PC as well */
+
+	mov.l	r15, @-r0					/* preserve registers backwards, from r15 to r1 */
+	mov.l	r14, @-r0
+	mov.l	r13, @-r0
+	mov.l	r12, @-r0
+	mov.l	r11, @-r0
+	mov.l	r10, @-r0
+	mov.l	r9, @-r0
+	mov.l	r8, @-r0
+	mov.l	r7, @-r0
+	mov.l	r6, @-r0
+	mov.l	r5, @-r0
+	mov.l	r4, @-r0
+	mov.l	r3, @-r0
+	mov.l	r2, @-r0
+	mov.l	r1, @-r0
+
+	mov	r0, r1
+	mov	#0, r0
+
+	mov.l	r0, @-r1					/* preserve r0 as explicit zero */
+
+	mov	#0, r0						/* set return value as zero */
+	rts
+END(libucontext_getcontext)

arch/sh/include/libucontext/bits.h

@@ -0,0 +1,29 @@
+#ifndef LIBUCONTEXT_BITS_H
+#define LIBUCONTEXT_BITS_H
+
+typedef unsigned long libucontext_greg_t, libucontext_gregset_t[16];
+typedef unsigned long libucontext_freg_t, libucontext_fpregset_t[16];
+typedef struct sigcontext {
+	unsigned long oldmask;
+	unsigned long gregs[16];
+	unsigned long pc, pr, sr;
+	unsigned long gbr, mach, macl;
+	unsigned long fpregs[16];
+	unsigned long xfpregs[16];
+	unsigned int fpscr, fpul, ownedfp;
+} libucontext_mcontext_t;
+
+typedef struct {
+	void *ss_sp;
+	int ss_flags;
+	size_t ss_size;
+} libucontext_stack_t;
+
+typedef struct libucontext_ucontext {
+	unsigned long uc_flags;
+	struct libucontext_ucontext *uc_link;
+	libucontext_stack_t uc_stack;
+	libucontext_mcontext_t uc_mcontext;
+} libucontext_ucontext_t;
+
+#endif

arch/sh/makecontext.c

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include <stddef.h>
+#include <stdarg.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdio.h>
+#include "defs.h"
+#include <libucontext/libucontext.h>
+
+
+extern void libucontext_trampoline(void);
+
+
+void
+libucontext_makecontext(libucontext_ucontext_t *ucp, void (*func)(void), int argc, ...)
+{
+	libucontext_greg_t *sp, *regp;
+	va_list va;
+	int i;
+
+	/* set up and align the stack */
+	sp = (libucontext_greg_t *) (((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size) & -4L);
+	sp -= argc > 4 ? argc - 4 : 0;
+
+	/* set up the context */
+	ucp->uc_mcontext.gregs[REG_SP] = (libucontext_greg_t) sp;
+	ucp->uc_mcontext.pr = (libucontext_greg_t) libucontext_trampoline;
+	ucp->uc_mcontext.pc = (libucontext_greg_t) func;
+	ucp->uc_mcontext.gregs[8] = (libucontext_greg_t) ucp->uc_link;
+
+	/* pass up to four args in r4-r7, rest on stack */
+	va_start(va, argc);
+
+	regp = &ucp->uc_mcontext.gregs[4];
+
+	for (i = 0; i < argc && i < 4; i++)
+		*regp++ = va_arg(va, libucontext_greg_t);
+
+	for (; i < argc; i++)
+		*sp++ = va_arg(va, libucontext_greg_t);
+
+	va_end(va);
+}
+
+#ifdef EXPORT_UNPREFIXED
+extern __typeof(libucontext_makecontext) makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+extern __typeof(libucontext_makecontext) __makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
+#endif

arch/sh/setcontext.S

@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include "defs.h"
+
+ALIAS(setcontext, libucontext_setcontext)
+ALIAS(__setcontext, libucontext_setcontext)
+
+FUNC(libucontext_setcontext)
+	mov	r4, r0
+
+	add	#(REG_OFFSET(5)), r0				/* restore GPRs r5-15 */
+	mov.l	@r0+, r5
+	mov.l	@r0+, r6
+	mov.l	@r0+, r7
+	mov.l	@r0+, r8
+	mov.l	@r0+, r9
+	mov.l	@r0+, r10
+	mov.l	@r0+, r11
+	mov.l	@r0+, r12
+	mov.l	@r0+, r13
+	mov.l	@r0+, r14
+	mov.l	@r0+, r15
+
+	mov.l	@r0+, r2					/* restore PR */
+	lds.l	@r0+, pr
+
+	mov.l	@r0+, r1					/* restore T-flag */
+	shlr	r1
+
+	add	#REG_SZ, r0					/* skip GBR (used for TLS) */
+
+	lds.l	@r0+, mach					/* load mach/macl registers */
+	lds.l	@r0+, macl
+
+	mov	r4, r0						/* bring r0 back to the top of the context */
+	add	#(REG_OFFSET(0)), r1				/* restore r0 into r1 (temporarily) */
+	mov.l	r1, @-r15					/* push to stack from r1 */
+	mov.l	r2, @-r15					/* push PC to stack */
+
+	mov.l	@(REG_OFFSET(1), r0), r1			/* restore real r1 */
+	mov.l	@(REG_OFFSET(2), r0), r2			/* restore real r2 */
+	mov.l	@(REG_OFFSET(3), r0), r3			/* restore real r2 */
+	mov.l	@(REG_OFFSET(4), r0), r4			/* restore real r2 */
+
+	mov.l	@r15+, r0					/* pop PC from stack */
+
+	jmp	@r0						/* jump to new PC */
+
+	mov.l	@r15+, r0					/* pop original r0 from stack */
+END(libucontext_setcontext)

arch/sh/swapcontext.S

@@ -0,0 +1,95 @@
+/*
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include "defs.h"
+
+ALIAS(swapcontext, libucontext_swapcontext)
+ALIAS(__swapcontext, libucontext_swapcontext)
+
+FUNC(libucontext_swapcontext)
+	mov	r4, r0						/* move r4 to r0, and increment by REG_OFFSET(REG_MACL) + REG_SZ. */
+	add	#(REG_OFFSET(REG_MACL + 1)), r0
+
+	sts.l	macl, @-r0					/* save macl/mach registers */
+	sts.l	mach, @-r0
+
+	stc.l	gbr, @-r0					/* save gbr register */
+
+	movt	r1						/* load T-flag into r1 */
+	mov.l	r1, @-r0					/* save T-flag as SR register */
+
+	sts.l	pr, @-r0					/* save current PR */
+	sts.l	pr, @-r0					/* save current PR as PC as well */
+
+	mov.l	r15, @-r0					/* preserve registers backwards, from r15 to r1 */
+	mov.l	r14, @-r0
+	mov.l	r13, @-r0
+	mov.l	r12, @-r0
+	mov.l	r11, @-r0
+	mov.l	r10, @-r0
+	mov.l	r9, @-r0
+	mov.l	r8, @-r0
+	mov.l	r7, @-r0
+	mov.l	r6, @-r0
+	mov.l	r5, @-r0
+	mov.l	r4, @-r0
+	mov.l	r3, @-r0
+	mov.l	r2, @-r0
+	mov.l	r1, @-r0
+
+	mov	r0, r1
+	mov	#0, r0
+
+	mov.l	r0, @-r1					/* preserve r0 as explicit zero */
+
+	mov	r5, r0						/* now restore the new context */
+
+	add	#(REG_OFFSET(6)), r0				/* restore GPRs r6-15 */
+	mov.l	@r0+, r6
+	mov.l	@r0+, r7
+	mov.l	@r0+, r8
+	mov.l	@r0+, r9
+	mov.l	@r0+, r10
+	mov.l	@r0+, r11
+	mov.l	@r0+, r12
+	mov.l	@r0+, r13
+	mov.l	@r0+, r14
+	mov.l	@r0+, r15
+
+	mov.l	@r0+, r2					/* restore PR */
+	lds.l	@r0+, pr
+
+	mov.l	@r0+, r1					/* restore T-flag */
+	shlr	r1
+
+	add	#REG_SZ, r0					/* skip GBR (used for TLS) */
+
+	lds.l	@r0+, mach					/* load mach/macl registers */
+	lds.l	@r0+, macl
+
+	mov	r5, r0						/* bring r0 back to the top of the context */
+	add	#(REG_OFFSET(0)), r1				/* restore r0 into r1 (temporarily) */
+	mov.l	r1, @-r15					/* push to stack from r1 */
+	mov.l	r2, @-r15					/* push PC to stack */
+
+	mov.l	@(REG_OFFSET(1), r0), r1			/* restore real r1 */
+	mov.l	@(REG_OFFSET(2), r0), r2			/* restore real r2 */
+	mov.l	@(REG_OFFSET(3), r0), r3			/* restore real r3 */
+	mov.l	@(REG_OFFSET(4), r0), r4			/* restore real r4 */
+	mov.l	@(REG_OFFSET(5), r0), r5			/* restore real r5 */
+
+	mov.l	@r15+, r0					/* pop PC from stack */
+
+	jmp	@r0						/* jump to new PC */
+
+	mov.l	@r15+, r0					/* pop original r0 from stack */
+END(libucontext_swapcontext)

arch/sh/trampoline.c

@@ -0,0 +1,3 @@
+#include "defs.h"
+#include <libucontext/libucontext.h>
+#include "common-trampoline.c"

arch/x86/defs.h

@@ -3,17 +3,53 @@
 
 #ifndef REG_GS
 # define REG_GS		(0)
+#endif
+
+#ifndef REG_FS
 # define REG_FS		(1)
+#endif
+
+#ifndef REG_ES
 # define REG_ES		(2)
+#endif
+
+#ifndef REG_DS
 # define REG_DS		(3)
+#endif
+
+#ifndef REG_EDI
 # define REG_EDI	(4)
+#endif
+
+#ifndef REG_ESI
 # define REG_ESI	(5)
+#endif
+
+#ifndef REG_EBP
 # define REG_EBP	(6)
+#endif
+
+#ifndef REG_ESP
 # define REG_ESP	(7)
+#endif
+
+#ifndef REG_EBX
 # define REG_EBX	(8)
+#endif
+
+#ifndef REG_EDX
 # define REG_EDX	(9)
+#endif
+
+#ifndef REG_ECX
 # define REG_ECX	(10)
+#endif
+
+#ifndef REG_EAX
 # define REG_EAX	(11)
+#endif
+
+#ifndef REG_EIP
 # define REG_EIP	(14)
 #endif
 
@@ -21,6 +57,9 @@
 
 #define MCONTEXT_GREGS	(20)
 
+#define FETCH_LINKPTR(dest) \
+	asm("movl (%%esp, %%ebx, 4), %0" : "=r" ((dest)));
+
 #include "common-defs.h"
 
 #endif

arch/x86/getcontext.S

@@ -12,9 +12,10 @@
 
 #include "defs.h"
 
-ALIAS(getcontext, __getcontext)
+ALIAS(getcontext, libucontext_getcontext)
+ALIAS(__getcontext, libucontext_getcontext)
 
-FUNC(__getcontext)
+FUNC(libucontext_getcontext)
 	/* load address of the ucontext structure */
 	movl	4(%esp), %eax
 
@@ -46,4 +47,4 @@ FUNC(__getcontext)
 	/* we're all done here, return 0 */
 	xorl	%eax, %eax
 	ret
-END(__getcontext)
+END(libucontext_getcontext)

arch/x86/include/libucontext/bits.h

@@ -0,0 +1,48 @@
+#ifndef LIBUCONTEXT_BITS_H
+#define LIBUCONTEXT_BITS_H
+
+#define REG_GS		(0)
+#define REG_FS		(1)
+#define REG_ES		(2)
+#define REG_DS		(3)
+#define REG_EDI		(4)
+#define REG_ESI		(5)
+#define REG_EBP		(6)
+#define REG_ESP		(7)
+#define REG_EBX		(8)
+#define REG_EDX		(9)
+#define REG_ECX		(10)
+#define REG_EAX		(11)
+#define REG_EIP		(14)
+
+typedef int libucontext_greg_t, libucontext_gregset_t[19];
+
+typedef struct libucontext_fpstate {
+	unsigned long cw, sw, tag, ipoff, cssel, dataoff, datasel;
+	struct {
+		unsigned short significand[4], exponent;
+	} _st[8];
+	unsigned long status;
+} *libucontext_fpregset_t;
+
+typedef struct {
+	libucontext_gregset_t gregs;
+	libucontext_fpregset_t fpregs;
+	unsigned long oldmask, cr2;
+} libucontext_mcontext_t;
+
+typedef struct {
+	void *ss_sp;
+	int ss_flags;
+	size_t ss_size;
+} libucontext_stack_t;
+
+typedef struct libucontext_ucontext {
+	unsigned long uc_flags;
+	struct libucontext_ucontext *uc_link;
+	libucontext_stack_t uc_stack;
+	libucontext_mcontext_t uc_mcontext;
+} libucontext_ucontext_t;
+
+#endif
+