[dpdk-dev] [PATCH 1/4 v3] compat: Add infrastructure to support symbol versioning
Neil Horman
nhorman at tuxdriver.com
Mon Sep 29 17:44:03 CEST 2014
Add initial pass header files to support symbol versioning.
---
Change notes
v2)
* Fixed ifdef in rte_compat.h to test for RTE_BUILD_SHARED_LIB instead of the
non-existant RTE_SYMBOL_VERSIONING
* Fixed VERSION_SYMBOL macro to add the needed extra @ to make versioning work
properly
* Improved/Clarified documentation
v3)
* Added missing macros to fully export the symver directive specification
Signed-off-by: Neil Horman <nhorman at tuxdriver.com>
CC: Thomas Monjalon <thomas.monjalon at 6wind.com>
CC: "Richardson, Bruce" <bruce.richardson at intel.com>
CC: "Gonzalez Monroy, Sergio" <sergio.gonzalez.monroy at intel.com>
---
lib/Makefile | 1 +
lib/librte_compat/Makefile | 38 ++++++++++++++++++
lib/librte_compat/rte_compat.h | 90 ++++++++++++++++++++++++++++++++++++++++++
mk/rte.lib.mk | 6 +++
4 files changed, 135 insertions(+)
create mode 100644 lib/librte_compat/Makefile
create mode 100644 lib/librte_compat/rte_compat.h
diff --git a/lib/Makefile b/lib/Makefile
index 10c5bb3..a85b55b 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -32,6 +32,7 @@
include $(RTE_SDK)/mk/rte.vars.mk
DIRS-$(CONFIG_RTE_LIBC) += libc
+DIRS-y += librte_compat
DIRS-$(CONFIG_RTE_LIBRTE_EAL) += librte_eal
DIRS-$(CONFIG_RTE_LIBRTE_MALLOC) += librte_malloc
DIRS-$(CONFIG_RTE_LIBRTE_RING) += librte_ring
diff --git a/lib/librte_compat/Makefile b/lib/librte_compat/Makefile
new file mode 100644
index 0000000..3415c7b
--- /dev/null
+++ b/lib/librte_compat/Makefile
@@ -0,0 +1,38 @@
+# BSD LICENSE
+#
+# Copyright(c) 2010-2014 Neil Horman <nhorman at tuxdriver.com>
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+# * Redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in
+# the documentation and/or other materials provided with the
+# distribution.
+# * Neither the name of Intel Corporation nor the names of its
+# contributors may be used to endorse or promote products derived
+# from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+include $(RTE_SDK)/mk/rte.vars.mk
+
+
+# install includes
+SYMLINK-y-include := rte_compat.h
+
+include $(RTE_SDK)/mk/rte.lib.mk
diff --git a/lib/librte_compat/rte_compat.h b/lib/librte_compat/rte_compat.h
new file mode 100644
index 0000000..0b76771
--- /dev/null
+++ b/lib/librte_compat/rte_compat.h
@@ -0,0 +1,90 @@
+/*-
+ * BSD LICENSE
+ *
+ * Copyright(c) 2010-2014 Neil Horman <nhorman at tuxdriver.com>.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _RTE_COMPAT_H_
+#define _RTE_COMPAT_H_
+
+/*
+ * This is just a stringification macro for use below.
+ */
+#define SA(x) #x
+
+#ifdef RTE_BUILD_SHARED_LIB
+
+/*
+ * Provides backwards compatibility when updating exported functions.
+ * When a symol is exported from a library to provide an API, it also provides a
+ * calling convention (ABI) that is embodied in its name, return type,
+ * arguments, etc. On occasion that function may need to change to accomodate
+ * new functionality, behavior, etc. When that occurs, it is desireable to
+ * allow for backwards compatibility for a time with older binaries that are
+ * dynamically linked to the dpdk. to support that the __vsym and
+ * VERSION_SYMBOL macros are created. They, in conjunction with the
+ * <library>_version.map file for a given library allow for multiple versions of
+ * a symbol to exist in a shared library so that older binaries need not be
+ * immediately recompiled. Their use is outlined in the following example:
+ * Assumptions: DPDK 1.(X) contains a function int foo(char *string)
+ * DPDK 1.(X+1) needs to change foo to be int foo(int index)
+ *
+ * To accomplish this:
+ * 1) Edit lib/<library>/library_version.map to add a DPDK_1.(X+1) node, in which
+ * foo is exported as a global symbol.
+ *
+ * 2) rename the existing function int foo(char *string) to
+ * int __vsym foo_v18(char *string)
+ *
+ * 3) Add this macro immediately below the function
+ * VERSION_SYMBOL(foo, _v18, 1.8);
+ *
+ * 4) Implement a new version of foo.
+ *
+ */
+#define VERSION_SYMBOL(b, e, v) __asm__(".symver " SA(b) SA(e) ", "SA(b)"@DPDK_"SA(v))
+#define BASE_SYMBOL(b, n) __asm__(".symver " SA(n) ", "SA(b)"@")
+#define BIND_DEFAULT_SYMBOL(b, v) __asm__(".symver " SA(b) ", "SA(b)"@@DPDK_"SA(v))
+#define __vsym __attribute__((used))
+
+#else
+/*
+ * No symbol versioning in use
+ */
+#define VERSION_SYMBOL(b, e, v)
+#define __vsym
+
+/*
+ * RTE_BUILD_SHARED_LIB
+ */
+#endif
+
+
+#endif /* _RTE_COMPAT_H_ */
diff --git a/mk/rte.lib.mk b/mk/rte.lib.mk
index f458258..82ac309 100644
--- a/mk/rte.lib.mk
+++ b/mk/rte.lib.mk
@@ -40,8 +40,12 @@ VPATH += $(SRCDIR)
ifeq ($(RTE_BUILD_SHARED_LIB),y)
LIB := $(patsubst %.a,%.so,$(LIB))
+
+CPU_LDFLAGS += --version-script=$(EXPORT_MAP)
+
endif
+
_BUILD = $(LIB)
_INSTALL = $(INSTALL-FILES-y) $(SYMLINK-FILES-y) $(RTE_OUTPUT)/lib/$(LIB)
_CLEAN = doclean
@@ -160,7 +164,9 @@ endif
$(RTE_OUTPUT)/lib/$(LIB): $(LIB)
@echo " INSTALL-LIB $(LIB)"
@[ -d $(RTE_OUTPUT)/lib ] || mkdir -p $(RTE_OUTPUT)/lib
+ifneq ($(LIB),)
$(Q)cp -f $(LIB) $(RTE_OUTPUT)/lib
+endif
#
# Clean all generated files
--
1.9.3
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