Commit 7c2acc70 authored by Peter Maydell's avatar Peter Maydell Committed by Anthony Liguori
Browse files

configure: Don't fall back to gthread coroutine backend



The gthread coroutine backend is broken and does not produce a working
QEMU; it is only useful for some very limited debugging situations.
Clean up the backend selection logic in configure so that it now runs
"if on windows use windows; else prefer ucontext; else sigaltstack".

To do this we refactor the configure code to separate out "test
whether we have a working ucontext", "pick a default if user didn't
specify" and "validate that user didn't specify something invalid",
rather than having all three of these run together. We also simplify
the Makefile logic so it just links in the backend the configure
script selects.
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Message-id: 1365419487-19867-3-git-send-email-peter.maydell@linaro.org
Signed-off-by: default avatarAnthony Liguori <aliguori@us.ibm.com>
parent 76ad07a4
......@@ -16,16 +16,7 @@ block-obj-y += qapi-types.o qapi-visit.o
block-obj-y += qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o
block-obj-y += qemu-coroutine-sleep.o
ifeq ($(CONFIG_UCONTEXT_COROUTINE),y)
block-obj-$(CONFIG_POSIX) += coroutine-ucontext.o
else
ifeq ($(CONFIG_SIGALTSTACK_COROUTINE),y)
block-obj-$(CONFIG_POSIX) += coroutine-sigaltstack.o
else
block-obj-$(CONFIG_POSIX) += coroutine-gthread.o
endif
endif
block-obj-$(CONFIG_WIN32) += coroutine-win32.o
block-obj-y += coroutine-$(CONFIG_COROUTINE_BACKEND).o
ifeq ($(CONFIG_VIRTIO)$(CONFIG_VIRTFS)$(CONFIG_PCI),yyy)
# Lots of the fsdev/9pcode is pulled in by vl.c via qemu_fsdev_add.
......
......@@ -3071,31 +3071,58 @@ fi
##########################################
# check and set a backend for coroutine
# default is ucontext, but always fallback to gthread
# windows autodetected by make
if test "$coroutine" = "" -o "$coroutine" = "ucontext"; then
if test "$darwin" != "yes"; then
cat > $TMPC << EOF
# We prefer ucontext, but it's not always possible. The fallback
# is sigcontext. gthread is not selectable except explicitly, because
# it is not functional enough to run QEMU proper. (It is occasionally
# useful for debugging purposes.) On Windows the only valid backend
# is the Windows-specific one.
ucontext_works=no
if test "$darwin" != "yes"; then
cat > $TMPC << EOF
#include <ucontext.h>
#ifdef __stub_makecontext
#error Ignoring glibc stub makecontext which will always fail
#endif
int main(void) { makecontext(0, 0, 0); return 0; }
EOF
if compile_prog "" "" ; then
coroutine_backend=ucontext
else
coroutine_backend=gthread
fi
if compile_prog "" "" ; then
ucontext_works=yes
fi
fi
if test "$coroutine" = ""; then
if test "$mingw32" = "yes"; then
coroutine=win32
elif test "$ucontext_works" = "yes"; then
coroutine=ucontext
else
coroutine=sigaltstack
fi
elif test "$coroutine" = "gthread" ; then
coroutine_backend=gthread
elif test "$coroutine" = "windows" ; then
coroutine_backend=windows
elif test "$coroutine" = "sigaltstack" ; then
coroutine_backend=sigaltstack
else
error_exit "unknown coroutine backend $coroutine"
case $coroutine in
windows)
if test "$mingw32" != "yes"; then
error_exit "'windows' coroutine backend only valid for Windows"
fi
# Unfortunately the user visible backend name doesn't match the
# coroutine-*.c filename for this case, so we have to adjust it here.
coroutine=win32
;;
ucontext)
if test "$ucontext_works" != "yes"; then
feature_not_found "ucontext"
fi
;;
gthread|sigaltstack)
if test "$mingw32" = "yes"; then
error_exit "only the 'windows' coroutine backend is valid for Windows"
fi
;;
*)
error_exit "unknown coroutine backend $coroutine"
;;
esac
fi
##########################################
......@@ -3402,7 +3429,7 @@ echo "GLX support $glx"
echo "libiscsi support $libiscsi"
echo "build guest agent $guest_agent"
echo "seccomp support $seccomp"
echo "coroutine backend $coroutine_backend"
echo "coroutine backend $coroutine"
echo "GlusterFS support $glusterfs"
echo "virtio-blk-data-plane $virtio_blk_data_plane"
echo "gcov $gcov_tool"
......@@ -3735,11 +3762,7 @@ if test "$rbd" = "yes" ; then
echo "CONFIG_RBD=y" >> $config_host_mak
fi
if test "$coroutine_backend" = "ucontext" ; then
echo "CONFIG_UCONTEXT_COROUTINE=y" >> $config_host_mak
elif test "$coroutine_backend" = "sigaltstack" ; then
echo "CONFIG_SIGALTSTACK_COROUTINE=y" >> $config_host_mak
fi
echo "CONFIG_COROUTINE_BACKEND=$coroutine" >> $config_host_mak
if test "$open_by_handle_at" = "yes" ; then
echo "CONFIG_OPEN_BY_HANDLE=y" >> $config_host_mak
......
......@@ -24,19 +24,7 @@ gcov-files-test-string-input-visitor-y = qapi/string-input-visitor.c
check-unit-y += tests/test-string-output-visitor$(EXESUF)
gcov-files-test-string-output-visitor-y = qapi/string-output-visitor.c
check-unit-y += tests/test-coroutine$(EXESUF)
ifeq ($(CONFIG_WIN32),y)
gcov-files-test-coroutine-y = coroutine-win32.c
else
ifeq ($(CONFIG_UCONTEXT_COROUTINE),y)
gcov-files-test-coroutine-y = coroutine-ucontext.c
else
ifeq ($(CONFIG_SIGALTSTACK_COROUTINE),y)
gcov-files-test-coroutine-y = coroutine-sigaltstack.c
else
gcov-files-test-coroutine-y = coroutine-gthread.c
endif
endif
endif
gcov-files-test-coroutine-y = coroutine-$(CONFIG_COROUTINE_BACKEND).c
check-unit-y += tests/test-visitor-serialization$(EXESUF)
check-unit-y += tests/test-iov$(EXESUF)
gcov-files-test-iov-y = util/iov.c
......
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