loongarch64: rewrite makecontext in C

also fix MCONTEXT_PC and MCONTEXT_GREGS so they actually read and write to/from
the correct addresses in the ucontext structure.

.gitignore

@@ -1,4 +1,3 @@
-include/libucontext/bits.h
 *.o
 examples/cooperative_threading
 test_libucontext

Makefile

@@ -17,9 +17,13 @@ ifeq ($(ARCH),$(filter $(ARCH),arm64))
 	override ARCH = aarch64
 endif
 
-LIBDIR := /lib
+prefix = /usr
-INCLUDEDIR := /usr/include
+libdir = ${prefix}/lib
-PKGCONFIGDIR := /usr/lib/pkgconfig
+shared_libdir = ${libdir}
+static_libdir = ${libdir}
+includedir = ${prefix}/include
+pkgconfigdir = ${prefix}/lib/pkgconfig
+
 CFLAGS ?= -ggdb3 -O2 -Wall
 CPPFLAGS := -Iinclude -Iarch/${ARCH} -Iarch/common
 ifneq ($(shell uname),Darwin)
@@ -27,12 +31,28 @@ ifneq ($(shell uname),Darwin)
 else
 	# Darwin does not support aliases
 	EXPORT_UNPREFIXED := no
+	CPPFLAGS += -D_XOPEN_SOURCE
 endif
 FREESTANDING := no
 
 ifeq ($(FREESTANDING),yes)
 	CPPFLAGS += -DFREESTANDING
-	EXPORT_UNPREFIXED = no
+	EXPORT_UNPREFIXED = no -Iarch/${ARCH}/include
+else
+	CPPFLAGS += -Iarch/common/include
+endif
+
+# ARM hard float support is presently broken.
+FORCE_SOFT_FLOAT := yes
+
+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)
@@ -67,18 +87,22 @@ else
 endif
 LIBUCONTEXT_STATIC_NAME = libucontext.a
 LIBUCONTEXT_PC = libucontext.pc
-LIBUCONTEXT_PATH = ${LIBDIR}/${LIBUCONTEXT_SONAME}
+LIBUCONTEXT_PATH = ${shared_libdir}/${LIBUCONTEXT_SONAME}
-LIBUCONTEXT_STATIC_PATH = ${LIBDIR}/${LIBUCONTEXT_STATIC_NAME}
+LIBUCONTEXT_STATIC_PATH = ${static_libdir}/${LIBUCONTEXT_STATIC_NAME}
 LIBUCONTEXT_HEADERS = \
-	include/libucontext/libucontext.h \
+	include/libucontext/libucontext.h
-	include/libucontext/bits.h
+ifeq ($(FREESTANDING),yes)
+LIBUCONTEXT_HEADERS += arch/${ARCH}/include/libucontext/bits.h
+else
+LIBUCONTEXT_HEADERS += arch/common/include/libucontext/bits.h
+endif
 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 = ${LIBDIR}/${LIBUCONTEXT_POSIX_SONAME}
+LIBUCONTEXT_POSIX_PATH = ${shared_libdir}/${LIBUCONTEXT_POSIX_SONAME}
-LIBUCONTEXT_POSIX_STATIC_PATH = ${LIBDIR}/${LIBUCONTEXT_POSIX_STATIC_NAME}
+LIBUCONTEXT_POSIX_STATIC_PATH = ${static_libdir}/${LIBUCONTEXT_POSIX_STATIC_NAME}
 
 ifeq ($(FREESTANDING),yes)
 	LIBUCONTEXT_POSIX_NAME =
@@ -96,10 +120,10 @@ ${LIBUCONTEXT_POSIX_STATIC_NAME}: ${LIBUCONTEXT_STATIC_NAME} ${LIBUCONTEXT_POSIX
 ${LIBUCONTEXT_POSIX_SONAME}: ${LIBUCONTEXT_POSIX_NAME}
 	ln -sf ${LIBUCONTEXT_POSIX_NAME} ${LIBUCONTEXT_POSIX_SONAME}
 
-${LIBUCONTEXT_STATIC_NAME}: ${LIBUCONTEXT_HEADERS} ${LIBUCONTEXT_OBJ}
+${LIBUCONTEXT_STATIC_NAME}: ${LIBUCONTEXT_OBJ}
 	$(AR) rcs ${LIBUCONTEXT_STATIC_NAME} ${LIBUCONTEXT_OBJ}
 
-${LIBUCONTEXT_NAME}: ${LIBUCONTEXT_HEADERS} ${LIBUCONTEXT_OBJ}
+${LIBUCONTEXT_NAME}: ${LIBUCONTEXT_OBJ}
 	$(CC) -fPIC -o ${LIBUCONTEXT_NAME} ${LIBUCONTEXT_LINKER_FLAGS} ${LIBUCONTEXT_OBJ} ${LDFLAGS}
 
 ${LIBUCONTEXT_SONAME}: ${LIBUCONTEXT_NAME}
@@ -107,8 +131,9 @@ ${LIBUCONTEXT_SONAME}: ${LIBUCONTEXT_NAME}
 
 ${LIBUCONTEXT_PC}: libucontext.pc.in
 	sed -e s:@LIBUCONTEXT_VERSION@:${LIBUCONTEXT_VERSION}:g \
-	    -e s:@LIBUCONTEXT_LIBDIR@:${LIBDIR}:g \
+	    -e s:@LIBUCONTEXT_SHARED_LIBDIR@:${shared_libdir}:g \
-	    -e s:@LIBUCONTEXT_INCLUDEDIR@:${INCLUDEDIR}:g $< > $@
+	    -e s:@LIBUCONTEXT_STATIC_LIBDIR@:${static_libdir}:g \
+	    -e s:@LIBUCONTEXT_INCLUDEDIR@:${includedir}:g $< > $@
 
 MANPAGES_SYMLINKS_3 = \
 	libucontext_getcontext.3 \
@@ -127,7 +152,7 @@ MANPAGES = ${MANPAGES_3}
 docs: ${MANPAGES}
 
 .c.o:
-	$(CC) -std=gnu99 -D_BSD_SOURCE -fPIC -DPIC ${CFLAGS} ${CPPFLAGS} -c -o $@ $<
+	$(CC) -std=gnu99 -D_DEFAULT_SOURCE -fPIC -DPIC ${CFLAGS} ${CPPFLAGS} -c -o $@ $<
 
 .S.o:
 	$(CC) -fPIC -DPIC ${CFLAGS} ${CPPFLAGS} ${ASFLAGS} -c -o $@ $<
@@ -147,9 +172,6 @@ libucontext_obj_clean:
 ${LIBUCONTEXT_PC}_clean:
 	rm -f ${LIBUCONTEXT_PC}
 
-bits_clean:
-	rm -f include/libucontext/bits.h
-
 ${LIBUCONTEXT_POSIX_NAME}_clean:
 	rm -f ${LIBUCONTEXT_POSIX_NAME}
 
@@ -180,7 +202,6 @@ 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
@@ -192,13 +213,13 @@ 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; \
+		install -D -m644 $$i ${DESTDIR}${includedir}/$$destfn; \
 	done
-	install -D -m644 ${LIBUCONTEXT_PC} ${DESTDIR}${PKGCONFIGDIR}/${LIBUCONTEXT_PC}
+	install -D -m644 ${LIBUCONTEXT_PC} ${DESTDIR}${pkgconfigdir}/${LIBUCONTEXT_PC}
-	if [ -n ${LIBUCONTEXT_POSIX_NAME} ]; then \
+	if [ -n "${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
@@ -216,7 +237,7 @@ check_libucontext_posix: test_libucontext_posix ${LIBUCONTEXT_POSIX_SONAME} ${LI
 	env LD_LIBRARY_PATH=$(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
+	$(CC) -std=gnu99 -D_DEFAULT_SOURCE ${CFLAGS} ${CPPFLAGS} $@.c -o $@ -L. -lucontext -lucontext_posix
 endif
 
 ifeq ($(EXPORT_UNPREFIXED),yes)
@@ -226,7 +247,7 @@ check_libucontext_bare_posixabi: test_libucontext_bare_posixabi ${LIBUCONTEXT_SO
 	env LD_LIBRARY_PATH=$(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
+	$(CC) -std=gnu99 -D_DEFAULT_SOURCE ${CFLAGS} ${CPPFLAGS} test_libucontext_posix.c -o $@ -L. -lucontext
 endif
 
 check_libucontext: test_libucontext ${LIBUCONTEXT_SONAME}
@@ -235,23 +256,11 @@ check_libucontext: test_libucontext ${LIBUCONTEXT_SONAME}
 check: check_libucontext
 
 test_libucontext: test_libucontext.c ${LIBUCONTEXT_NAME}
-	$(CC) -std=gnu99 -D_BSD_SOURCE ${CFLAGS} ${CPPFLAGS} $@.c -o $@ -L. -lucontext
+	$(CC) -std=gnu99 -D_DEFAULT_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
+	$(CC) -std=gnu99 -D_DEFAULT_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}

NEWS

@@ -1,3 +1,38 @@
+Changes from 1.3 to 1.3.1
+-------------------------
+
+* Disable hard-float support on ARM by default.
+
+* Fix up getcontext/swapcontext return values on LoongArch.
+
+* Fix assembler warnings when building on LoongArch.
+
+Changes from 1.2 to 1.3
+-----------------------
+
+* Fix up getcontext/swapcontext return values across a few ports.
+  Patches contributed for ARM and test suite by Volker Christian.
+
+* Add support for hard-float on ARM.
+  Patches contributed by Richard Campbell.
+
+* Align build system variables with those used by Automake.
+  Patch contributed by Ismael Luceno.
+
+* Fix sporadic parallel build failures.
+  Patches contributed by Jim Hauxwell.
+
+* Ensure frame pointers are omitted when using the C trampoline.
+  Patch contributed by Sören Tempel.
+
+* Define _XOPEN_SOURCE when building on Darwin.
+  Patch contributed by L. Pereira.
+
+* Add support for building the manpages with Meson.
+  Patch contributed by matoro.
+
+* Migrate build from _BSD_SOURCE to _DEFAULT_SOURCE.
+
 Changes from 1.1 to 1.2
 -----------------------
 

README.md

@@ -31,7 +31,7 @@ target to do it.
 |    riscv64   | ✓             |         | ✓                     | ✓                 |
 |     s390x    | ✓             |         | ✓                     |                   |
 |      sh      | ✓             |         | ✓                     | ✓                 |
-|      x86     | ✓             |         | ✓                     | ✓                 |
+|      x86     | ✓             |         | ✓                     |                   |
 |    x86_64    | ✓             |         | ✓                     | ✓                 |
 
 
@@ -101,4 +101,5 @@ ucontext functions:
   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.
+  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

@@ -1 +1 @@
-1.2
+1.3.1

arch/aarch64/getcontext.S

@@ -22,23 +22,8 @@ ALIAS(__getcontext, libucontext_getcontext)
 PROC_NAME(libucontext_getcontext):
 	str	xzr, [x0, #REG_OFFSET(0)]
 
-	/* save GPRs */
+	/* save x2 and x3 for reuse */
-	stp	x0, x1,   [x0, #REG_OFFSET(0)]
 	stp	x2, x3,   [x0, #REG_OFFSET(2)]
-	stp	x4, x5,   [x0, #REG_OFFSET(4)]
-	stp	x6, x7,   [x0, #REG_OFFSET(6)]
-	stp	x8, x9,   [x0, #REG_OFFSET(8)]
-	stp	x10, x11, [x0, #REG_OFFSET(10)]
-	stp	x12, x13, [x0, #REG_OFFSET(12)]
-	stp	x14, x15, [x0, #REG_OFFSET(14)]
-	stp	x16, x17, [x0, #REG_OFFSET(16)]
-	stp	x18, x19, [x0, #REG_OFFSET(18)]
-	stp	x20, x21, [x0, #REG_OFFSET(20)]
-	stp	x22, x23, [x0, #REG_OFFSET(22)]
-	stp	x24, x25, [x0, #REG_OFFSET(24)]
-	stp	x26, x27, [x0, #REG_OFFSET(26)]
-	stp	x28, x29, [x0, #REG_OFFSET(28)]
-	str	x30,      [x0, #REG_OFFSET(30)]
 
 	/* save current program counter in link register */
 	str	x30, [x0, #PC_OFFSET]
@@ -56,6 +41,26 @@ PROC_NAME(libucontext_getcontext):
 	stp q12, q13, [x2, #208]
 	stp q14, q15, [x2, #240]
 
+	/* save GPRs and return value 0 */
+	mov	x2, x0
 	mov	x0, #0
+
+	stp	x0, x1,   [x2, #REG_OFFSET(0)]
+	/* x2 and x3 have already been saved */
+	stp	x4, x5,   [x2, #REG_OFFSET(4)]
+	stp	x6, x7,   [x2, #REG_OFFSET(6)]
+	stp	x8, x9,   [x2, #REG_OFFSET(8)]
+	stp	x10, x11, [x2, #REG_OFFSET(10)]
+	stp	x12, x13, [x2, #REG_OFFSET(12)]
+	stp	x14, x15, [x2, #REG_OFFSET(14)]
+	stp	x16, x17, [x2, #REG_OFFSET(16)]
+	stp	x18, x19, [x2, #REG_OFFSET(18)]
+	stp	x20, x21, [x2, #REG_OFFSET(20)]
+	stp	x22, x23, [x2, #REG_OFFSET(22)]
+	stp	x24, x25, [x2, #REG_OFFSET(24)]
+	stp	x26, x27, [x2, #REG_OFFSET(26)]
+	stp	x28, x29, [x2, #REG_OFFSET(28)]
+	str	x30,      [x2, #REG_OFFSET(30)]
+
 	ret
 END(libucontext_getcontext)

arch/arm/defs.h

@@ -2,8 +2,11 @@
 
 #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 END(__proc)
 
 #define FETCH_LINKPTR(dest) \
 	asm("movs    %0, r4" : "=r" ((dest)))

arch/arm/getcontext.S

@@ -22,6 +22,27 @@ FUNC(libucontext_getcontext)
 	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

arch/arm/include/libucontext/bits.h

@@ -23,6 +23,8 @@ typedef struct libucontext_ucontext {
 	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/setcontext.S

@@ -16,6 +16,22 @@ 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
+
 	/* copy all of the current registers into the ucontext structure */
 	add	r14, r0, #REG_OFFSET(0)
 	ldmia	r14, {r0-r12}

arch/arm/swapcontext.S

@@ -16,11 +16,33 @@ ALIAS(swapcontext, libucontext_swapcontext)
 ALIAS(__swapcontext, libucontext_swapcontext)
 
 FUNC(libucontext_swapcontext)
-	/* copy all of the current registers into the ucontext structure */
+#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
+
+ 	/* copy all of the current registers into the ucontext structure */
+ 	str	r13, [r0,#REG_OFFSET(13)]
+ 	str	r14, [r0,#REG_OFFSET(15)]
 	add	r2, r0, #REG_OFFSET(0)
+	/* copy r0 with value 0 to indicate success (return value 0) */
+	mov r0, #0
 	stmia	r2, {r0-r12}
-	str	r13, [r0,#REG_OFFSET(13)]
-	str	r14, [r0,#REG_OFFSET(15)]
 	
 	/* load new registers from the second ucontext structure */
 	add	r14, r1, #REG_OFFSET(0)

arch/common/common-defs.h

@@ -40,6 +40,8 @@
 	ENT(__proc)					\
 PROC_NAME(__proc):					\
 	SETUP_FRAME(__proc)
+
+#ifndef END
 #ifdef __clang__
 #define END(__proc)
 #else
@@ -47,6 +49,7 @@ PROC_NAME(__proc):					\
 	.end	__proc;					\
 	.size	__proc,.-__proc;
 #endif
+#endif
 
 #ifdef EXPORT_UNPREFIXED
 #define ALIAS(__alias, __real)				\

arch/common/common-trampoline.c

@@ -14,7 +14,19 @@
 #include <stdlib.h>
 #include <stdio.h>
 
+/* We need to make sure that the C compiler doesn't push any
+ * additional data to the stack frame. Otherwise, assumptions
+ * made by the architecture-specific implementation of the
+ * FETCH_LINKPTR() macro about the location of the linkptr,
+ * relative to the stack pointer, will not hold.
+ *
+ * Hence, we compile this function with -fomit-frame-pointer
+ * and use the register storage-class specifier for all local
+ * vars. Note that the latter is just a "suggestion" (see C99).
+ */
+
 __attribute__ ((visibility ("hidden")))
+__attribute__ ((optimize ("omit-frame-pointer")))
 void
 libucontext_trampoline(void)
 {

arch/loongarch64/defs.h

@@ -45,11 +45,17 @@
 /* frame pointer is actually $22 */
 #define REG_FP		(22)
 
+/* $s0 is $23 */
+#define REG_S0		(23)
+
+/* $ra is $1 */
+#define REG_RA		(1)
+
 /* offset to mc_gregs in ucontext_t */
-#define MCONTEXT_GREGS	(48)
+#define MCONTEXT_GREGS	(184)
 
 /* offset to PC in ucontext_t */
-#define MCONTEXT_PC	(40)
+#define MCONTEXT_PC	(176)
 
 /* offset to uc_link in ucontext_t */
 #define UCONTEXT_UC_LINK	(8)

arch/loongarch64/getcontext.S

@@ -35,11 +35,14 @@ FUNC(libucontext_getcontext)
 	st.d	$s8, $a0, REG_OFFSET(31)
 
 	st.d	$a2, $a0, REG_OFFSET(3)
+	st.d	$zero, $a0, REG_OFFSET(4)
 	st.d	$a3, $a0, REG_OFFSET(22)
 	st.d	$ra, $a0, REG_OFFSET(1)
 
 	st.d	$ra, $a0, (MCONTEXT_PC)
 
+	move	$a0, $zero
+
 	POP_FRAME(libucontext_getcontext)
 
 	jr	$ra

arch/loongarch64/makecontext.S

@@ -1,108 +0,0 @@
-/*
- * 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/makecontext.c

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2024 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] = (libucontext_greg_t) ucp->uc_link;
+	ucp->uc_mcontext.__gregs[REG_SP] = (libucontext_greg_t) sp;
+	ucp->uc_mcontext.__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/loongarch64/setcontext.S

@@ -49,7 +49,7 @@ FUNC(libucontext_setcontext)
 	ld.d	$t8, $t5, (MCONTEXT_PC)
 
 	jr	$t8
-	move	$v0, $zero
+	move	$a0, $zero
 
 	POP_FRAME(libucontext_setcontext)
 END(libucontext_setcontext)

arch/loongarch64/swapcontext.S

@@ -39,6 +39,7 @@ FUNC(libucontext_swapcontext)
 	st.d	$s8, $t5, REG_OFFSET(31)
 
 	st.d	$a3, $t5, REG_OFFSET(3)
+	st.d	$zero, $t5, REG_OFFSET(4)
 	st.d	$a4, $t5, REG_OFFSET(22)
 	st.d	$ra, $t5, REG_OFFSET(1)
 
@@ -77,7 +78,7 @@ FUNC(libucontext_swapcontext)
 	ld.d	$t8, $t4, (MCONTEXT_PC)
 
 	jr	$t8
-	move	$v0, $zero
+	move	$a0, $zero
 
 fail:
 	la.global	$t8, exit
@@ -85,5 +86,5 @@ fail:
 	POP_FRAME(libucontext_swapcontext)
 
 	jirl	$ra, $t8, 0
-	move	$v0, $zero
+	move	$a0, $zero
 END(libucontext_swapcontext)

arch/or1k/getcontext.S

@@ -19,8 +19,8 @@ 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(9)(r3), r9			/* link register */
-	l.sw		REG_OFFSET(11)(r3), r9
+	l.sw		REG_OFFSET(11)(r3), r0			/* return value is 0 */
 
 	l.sw		REG_OFFSET(10)(r3), r10			/* store r10 for TLS */
 
@@ -34,6 +34,6 @@ FUNC(libucontext_getcontext)
 	l.sw		REG_OFFSET(28)(r3), r28
 	l.sw		REG_OFFSET(30)(r3), r30
 
-	l.jr		r9
 	l.ori		r11, r0, 0
+	l.jr		r9
 END(libucontext_getcontext)

arch/or1k/swapcontext.S

@@ -20,8 +20,8 @@ FUNC(libucontext_swapcontext)
 	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(9)(r3), r9			/* link register */
-	l.sw		REG_OFFSET(11)(r3), r9
+	l.sw		REG_OFFSET(11)(r3), r0			/* return value is zero */
 
 	l.sw		REG_OFFSET(10)(r3), r10			/* store r10 for TLS */
 
@@ -63,6 +63,6 @@ FUNC(libucontext_swapcontext)
 	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
+	l.jr		r9					/* jump to new starting address */
 END(libucontext_swapcontext)

arch/riscv32/getcontext.S

@@ -25,8 +25,8 @@ FUNC(libucontext_getcontext)
 	sw s1, REG_OFFSET(REG_S1)(a0)
 
 	/* return register block */
-	sw a0, REG_OFFSET(REG_A0)(a0)
+	sw x0, REG_OFFSET(REG_A0)(a0)
-	sw a1, REG_OFFSET(REG_A1)(a0)
+	sw x0, REG_OFFSET(REG_A1)(a0)
 
 	/* second saved register block */
 	sw s2, REG_OFFSET(REG_S2)(a0)
@@ -41,5 +41,6 @@ FUNC(libucontext_getcontext)
 	sw s11, REG_OFFSET(REG_S11)(a0)
 
 	/* done saving, return */
+	mv a0, x0
 	ret
 END(libucontext_getcontext)

arch/riscv32/swapcontext.S

@@ -28,8 +28,8 @@ FUNC(libucontext_swapcontext)
 	sw s1, REG_OFFSET(REG_S1)(a0)
 
 	/* return register block */
-	sw a0, REG_OFFSET(REG_A0)(a0)
+	sw x0, REG_OFFSET(REG_A0)(a0)
-	sw a1, REG_OFFSET(REG_A1)(a0)
+	sw x0, REG_OFFSET(REG_A1)(a0)
 
 	/* second saved register block */
 	sw s2, REG_OFFSET(REG_S2)(a0)

arch/riscv64/getcontext.S

@@ -25,8 +25,8 @@ FUNC(libucontext_getcontext)
 	sd s1, REG_OFFSET(REG_S1)(a0)
 
 	/* return register block */
-	sd a0, REG_OFFSET(REG_A0)(a0)
+	sd x0, REG_OFFSET(REG_A0)(a0)
-	sd a1, REG_OFFSET(REG_A1)(a0)
+	sd x0, REG_OFFSET(REG_A1)(a0)
 
 	/* second saved register block */
 	sd s2, REG_OFFSET(REG_S2)(a0)
@@ -41,5 +41,6 @@ FUNC(libucontext_getcontext)
 	sd s11, REG_OFFSET(REG_S11)(a0)
 
 	/* done saving, return */
+	mv a0, x0
 	ret
 END(libucontext_getcontext)

arch/riscv64/swapcontext.S

@@ -28,8 +28,8 @@ FUNC(libucontext_swapcontext)
 	sd s1, REG_OFFSET(REG_S1)(a0)
 
 	/* return register block */
-	sd a0, REG_OFFSET(REG_A0)(a0)
+	sd x0, REG_OFFSET(REG_A0)(a0)
-	sd a1, REG_OFFSET(REG_A1)(a0)
+	sd x0, REG_OFFSET(REG_A1)(a0)
 
 	/* second saved register block */
 	sd s2, REG_OFFSET(REG_S2)(a0)

arch/s390x/swapcontext.S

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2020 Ariadne Conill <ariadne@dereferenced.org>
+ * Copyright (c) 2018, 2020, 2024 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
@@ -19,12 +19,14 @@ FUNC(libucontext_swapcontext)
 	lgr	%r1, %r2			/* use %r1 to save current context to */
 	lgr	%r0, %r3			/* use %r0 for source context */
 
+	la	%r2, 0				/* zero out future return value */
+
 	stam	%a0, %a15, AREG_OFFSET(0)(%r1)	/* store access registers */
 	stmg	%r0, %r15, REG_OFFSET(0)(%r1)	/* store general-purpose registers */
 
-	lgr	%r2, %r0			/* swap %r0 to %r2 (XXX: figure out why it hates loading from %r0) */
+	lgr	%r5, %r0			/* copy %r0 to %r5 so that %r0 doesn't get clobbered */
-	lam	%a2, %a15, AREG_OFFSET(2)(%r2)	/* load access registers, but skip %a0 and %a1 which are for TLS */
+	lam	%a2, %a15, AREG_OFFSET(2)(%r5)	/* load access registers, but skip %a0 and %a1 which are for TLS */
-	lmg	%r0, %r15, REG_OFFSET(0)(%r2)	/* load general-purpose registers */
+	lmg	%r0, %r15, REG_OFFSET(0)(%r5)	/* load general-purpose registers */
 
 	br	%r14				/* return to new link register address */
 END(libucontext_swapcontext)

arch/x86/defs.h

@@ -57,9 +57,6 @@
 
 #define MCONTEXT_GREGS	(20)
 
-#define FETCH_LINKPTR(dest) \
-	asm("movl (%%esp, %%ebx, 4), %0" : "=r" ((dest)));
-
 #include "common-defs.h"
 
 #endif

arch/x86/startcontext.S

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2018, 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"
+
+FUNC(libucontext_trampoline)
+	/* get the proper context into position and test for NULL */
+	leal	(%esp,%ebx,4), %esp
+	cmpl	$0, (%esp)
+
+	/* restore global offset table, exit@plt and libucontext_setcontext@plt need this */
+	call	__i686_get_pc_thunk_bx
+	addl	$_GLOBAL_OFFSET_TABLE_, %ebx
+
+	/* if we have no linked context, lets get out of here */
+	je	no_linked_context
+
+	/* call setcontext to switch to the linked context */
+	call	libucontext_setcontext@plt
+	movl	%eax, (%esp)
+
+no_linked_context:
+	/* we are returning into a null context, it seems, so maybe we should exit */
+	call	exit@plt
+
+	/* something is really hosed, call hlt to force termination */
+	hlt
+
+__i686_get_pc_thunk_bx:
+	mov	(%esp), %ebx
+	ret
+END(libucontext_trampoline)

arch/x86/trampoline.c

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

doc/meson.build

@@ -0,0 +1,21 @@
+scdoc = find_program('scdoc', required: true)
+
+custom_target(
+  'libucontext.3',
+  output: 'libucontext.3',
+  input: 'libucontext.scd',
+  command: [ scdoc ],
+  feed: true,
+  capture: true,
+  install: true,
+  install_dir: get_option('mandir') / 'man3'
+)
+
+if meson.version().version_compare('>=0.61.0')
+  foreach link : [ 'get', 'make', 'set', 'swap' ]
+    install_symlink('libucontext_' + link + 'context.3',
+      pointing_to: 'libucontext.3',
+      install_dir: get_option('mandir') / 'man3'
+    )
+  endforeach
+endif

include/libucontext/libucontext.h

@@ -4,9 +4,17 @@
 #include <stddef.h>
 #include <libucontext/bits.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 int  libucontext_getcontext(libucontext_ucontext_t *);
 void libucontext_makecontext(libucontext_ucontext_t *, void (*)(), int, ...);
 int  libucontext_setcontext(const libucontext_ucontext_t *);
 int  libucontext_swapcontext(libucontext_ucontext_t *, const libucontext_ucontext_t *);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif

libucontext.pc.in

@@ -1,8 +1,9 @@
-libdir=@LIBUCONTEXT_LIBDIR@
+libdir=@LIBUCONTEXT_SHARED_LIBDIR@
+static_libdir=@LIBUCONTEXT_STATIC_LIBDIR@
 includedir=@LIBUCONTEXT_INCLUDEDIR@
 
 Name: libucontext
 Version: @LIBUCONTEXT_VERSION@
 Description: ucontext library implementation (standalone)
-Libs: -L${libdir} -lucontext
+Libs: -L${libdir} -L${static_libdir} -lucontext
 Cflags: -I${includedir}

meson.build

@@ -1,7 +1,7 @@
 project(
   'libucontext',
   'c',
-  meson_version : '>=0.55.0',
+  meson_version : '>=0.59.0',
   default_options: ['c_std=gnu11', 'default_library=both'],
   version : run_command('head', files('VERSION')).stdout()
 )
@@ -56,7 +56,7 @@ project_includes = [
 ]
 
 build_args = [
-  '-D_BSD_SOURCE'
+  '-D_DEFAULT_SOURCE'
 ]
 
 
@@ -144,9 +144,8 @@ endif
 # Docs
 # ====
 
-# TODO: meson.build for docs
+if not meson.is_subproject() and get_option('docs')
-if not meson.is_subproject()
+  subdir('doc')
-  #subdir('docs')
 endif
 
 # ==========

meson_options.txt

@@ -4,3 +4,5 @@ option('export_unprefixed', type : 'boolean', value : true,
        description: 'Export POSIX 2004 ucontext names as alises')
 option('cpu', type : 'string', value : '',
        description: 'Target CPU architecture for cross compile')
+option('docs', type : 'boolean', value : false,
+       description: 'Build and install man pages')

test_libucontext.c

@@ -9,6 +9,9 @@
 #include <string.h>
 #include <libucontext/libucontext.h>
 
+#define handle_error(msg) \
+           do { perror(msg); exit(EXIT_FAILURE); } while (0)
+
 static libucontext_ucontext_t ctx[3];
 
 
@@ -36,7 +39,8 @@ static void f1 (int a, int b, int c, int d, int e, int f, int g, int h, int i, i
 	printf("looks like all arguments are passed correctly\n");
 
 	printf("swap back to f2\n");
-	libucontext_swapcontext(&ctx[1], &ctx[2]);
+	if (libucontext_swapcontext(&ctx[1], &ctx[2]) != 0)
+		handle_error("libucontext_swapcontext");
 	printf("finish f1\n");
 }
 
@@ -44,7 +48,8 @@ static void f1 (int a, int b, int c, int d, int e, int f, int g, int h, int i, i
 static void f2 (void) {
 	printf("start f2\n");
 	printf("swap to f1\n");
-	libucontext_swapcontext(&ctx[2], &ctx[1]);
+	if (libucontext_swapcontext(&ctx[2], &ctx[1]) != 0)
+		handle_error("libucontext_swapcontext");
 	printf("finish f2, should swap to f1\n");
 }
 
@@ -63,7 +68,8 @@ int main (int argc, const char *argv[]) {
 	printf("setting up context 1\n");
 
 
-	libucontext_getcontext(&ctx[1]);
+	if (libucontext_getcontext(&ctx[1]) != 0)
+		handle_error("libucontext_getcontext");
 	ctx[1].uc_stack.ss_sp = st1;
 	ctx[1].uc_stack.ss_size = sizeof st1;
 	ctx[1].uc_link = &ctx[0];
@@ -83,16 +89,20 @@ int main (int argc, const char *argv[]) {
 	printf("doing initial swapcontext\n");
 
 
-	libucontext_swapcontext(&ctx[0], &ctx[2]);
+	if (libucontext_swapcontext(&ctx[0], &ctx[2]) != 0)
+		handle_error("libucontext_swapcontext");
 
 
 	printf("returned from initial swapcontext\n");
 
 
 	/* test ability to use getcontext/setcontext without makecontext */
-	libucontext_getcontext(&ctx[1]);
+	if (libucontext_getcontext(&ctx[1]) != 0)
+		handle_error("libucontext_getcontext");
 	printf("done = %d\n", done);
-	if (done++ == 0) libucontext_setcontext(&ctx[1]);
+	if (done++ == 0)
+		if (libucontext_setcontext(&ctx[1]) != 0)
+			handle_error("libucontext_setcontext");
 	if (done != 2) {
 		fprintf(stderr, "wrong value for done.  got %d, expected 2\n", done);
 		abort();

test_libucontext_posix.c

@@ -9,6 +9,9 @@
 #include <string.h>
 #include <ucontext.h>
 
+#define handle_error(msg) \
+           do { perror(msg); exit(EXIT_FAILURE); } while (0)
+
 static ucontext_t ctx[3];
 
 
@@ -36,7 +39,8 @@ static void f1 (int a, int b, int c, int d, int e, int f, int g, int h, int i, i
 	printf("looks like all arguments are passed correctly\n");
 
 	printf("swap back to f2\n");
-	swapcontext(&ctx[1], &ctx[2]);
+	if (swapcontext(&ctx[1], &ctx[2]) != 0)
+		handle_error("swapcontext");
 	printf("finish f1\n");
 }
 
@@ -44,7 +48,8 @@ static void f1 (int a, int b, int c, int d, int e, int f, int g, int h, int i, i
 static void f2 (void) {
 	printf("start f2\n");
 	printf("swap to f1\n");
-	swapcontext(&ctx[2], &ctx[1]);
+	if (swapcontext(&ctx[2], &ctx[1]) != 0)
+		handle_error("swapcontext");
 	printf("finish f2, should swap to f1\n");
 }
 
@@ -67,7 +72,7 @@ int main (int argc, const char *argv[]) {
 	ctx[1].uc_stack.ss_sp = st1;
 	ctx[1].uc_stack.ss_size = sizeof st1;
 	ctx[1].uc_link = &ctx[0];
-	makecontext(&ctx[1], f1, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+	makecontext(&ctx[1], (void *) f1, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
 
 
 	printf("setting up context 2\n");
@@ -77,22 +82,25 @@ int main (int argc, const char *argv[]) {
 	ctx[2].uc_stack.ss_sp = st2;
 	ctx[2].uc_stack.ss_size = sizeof st2;
 	ctx[2].uc_link = &ctx[1];
-	makecontext(&ctx[2], f2, 0);
+	makecontext(&ctx[2], (void *) f2, 0);
 
 
 	printf("doing initial swapcontext\n");
 
 
-	swapcontext(&ctx[0], &ctx[2]);
+	if (swapcontext(&ctx[0], &ctx[2]) != 0)
-
+		handle_error("swapcontext");
 
 	printf("returned from initial swapcontext\n");
 
 
 	/* test ability to use getcontext/setcontext without makecontext */
-	getcontext(&ctx[1]);
+	if (getcontext(&ctx[1]) != 0)
+		handle_error("getcontext");
 	printf("done = %d\n", done);
-	if (done++ == 0) setcontext(&ctx[1]);
+	if (done++ == 0)
+		if (setcontext(&ctx[1]) != 0)
+			handle_error("setcontext");
 	if (done != 2) {
 		fprintf(stderr, "wrong value for done.  got %d, expected 2\n", done);
 		abort();