diff mbox

[dpdk-dev,v8,1/4] compat: Add infrastructure to support symbol versioning

Message ID 1421941756-30948-1-git-send-email-nhorman@tuxdriver.com (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Neil Horman Jan. 22, 2015, 3:49 p.m. UTC
Add initial pass header files to support symbol versioning.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Thomas Monjalon <thomas.monjalon@6wind.com>
CC: "Richardson, Bruce" <bruce.richardson@intel.com>
CC: "Gonzalez Monroy, Sergio" <sergio.gonzalez.monroy@intel.com>

---
Change Notes:
V2)
	Moved ifeq to _INSTALL target

V3)
	Undo V2 changes and make librte_compat use the rte.install.mk file
instead

v4)
	changed --version-script to accept SRCDIR in this patch at per request
	documented versioning macros
	cleaned up macro parameter consistency
	converted SA macro to RTE_STR macro
	fixed copyright
---
 lib/Makefile                   |   1 +
 lib/librte_compat/Makefile     |  38 +++++++++++++
 lib/librte_compat/rte_compat.h | 117 +++++++++++++++++++++++++++++++++++++++++
 mk/rte.lib.mk                  |   4 ++
 4 files changed, 160 insertions(+)
 create mode 100644 lib/librte_compat/Makefile
 create mode 100644 lib/librte_compat/rte_compat.h

Comments

Thomas Monjalon Feb. 2, 2015, 4:41 p.m. UTC | #1
2015-01-22 10:49, Neil Horman:
> Add initial pass header files to support symbol versioning.
> 
> Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
[...]
> --- /dev/null
> +++ b/lib/librte_compat/Makefile
> @@ -0,0 +1,38 @@
> +#   BSD LICENSE
> +#
> +#   Copyright(c) 2013 Neil Horman <nhorman@tuxdriver.com>
[...]
> --- /dev/null
> +++ b/lib/librte_compat/rte_compat.h
> @@ -0,0 +1,117 @@
> +/*-
> + *   BSD LICENSE
> + *
> + *   Copyright(c) 2010 Neil Horman <nhorman@tuxdriver.com>.

These years (2010, 2013) are weird. Your patchset is not so old ;)

> + *     * Neither the name of Intel Corporation nor the names of its

Are you sure that's what you mean?
In general, we put the name of our company here.
Neil Horman Feb. 2, 2015, 5:30 p.m. UTC | #2
On Mon, Feb 02, 2015 at 05:41:48PM +0100, Thomas Monjalon wrote:
> 2015-01-22 10:49, Neil Horman:
> > Add initial pass header files to support symbol versioning.
> > 
> > Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
> [...]
> > --- /dev/null
> > +++ b/lib/librte_compat/Makefile
> > @@ -0,0 +1,38 @@
> > +#   BSD LICENSE
> > +#
> > +#   Copyright(c) 2013 Neil Horman <nhorman@tuxdriver.com>
> [...]
> > --- /dev/null
> > +++ b/lib/librte_compat/rte_compat.h
> > @@ -0,0 +1,117 @@
> > +/*-
> > + *   BSD LICENSE
> > + *
> > + *   Copyright(c) 2010 Neil Horman <nhorman@tuxdriver.com>.
> 
> These years (2010, 2013) are weird. Your patchset is not so old ;)
> 
> > + *     * Neither the name of Intel Corporation nor the names of its
> 
> Are you sure that's what you mean?
> In general, we put the name of our company here.
> 

The copyright was borrowed from the header file in another directory, I can
update it if you like, though I'm not sure how relevant it is.

As for the Intel language, I can certainly remove it.
Neil

> -- 
> Thomas
>
diff mbox

Patch

diff --git a/lib/Makefile b/lib/Makefile
index 0ffc982..d617d81 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -31,6 +31,7 @@ 
 
 include $(RTE_SDK)/mk/rte.vars.mk
 
+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..0bab870
--- /dev/null
+++ b/lib/librte_compat/Makefile
@@ -0,0 +1,38 @@ 
+#   BSD LICENSE
+#
+#   Copyright(c) 2013 Neil Horman <nhorman@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.install.mk
diff --git a/lib/librte_compat/rte_compat.h b/lib/librte_compat/rte_compat.h
new file mode 100644
index 0000000..d7cc176
--- /dev/null
+++ b/lib/librte_compat/rte_compat.h
@@ -0,0 +1,117 @@ 
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010 Neil Horman <nhorman@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_
+#include <rte_common.h>
+
+#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.
+ * 	char foo(int value, int otherval) { ...}
+ *
+ * 5) Mark the newest version as the default version
+ * 	BIND_DEFAULT_SYMBOL(foo, 1.9);
+ *
+ */
+
+/* 
+ * Macro Parameters:
+ * b - function base name
+ * e - function version extension, to be concatenated with base name
+ * n - function symbol version string to be applied
+ */
+
+/*
+ * VERSION_SYMBOL
+ * Creates a symbol version table entry binding symbol <b>@DPDK_<n> to the internal
+ * function name <b>_<e>
+ */ 
+#define VERSION_SYMBOL(b, e, n) __asm__(".symver " RTE_STR(b) RTE_STR(e) ", "RTE_STR(b)"@DPDK_"RTE_STR(n))
+
+/*
+ * BASE_SYMBOL
+ * Creates a symbol version table entry binding unversioned symbol <b> 
+ * to the internal function <b>_<e>
+ */ 
+#define BASE_SYMBOL(b, e) __asm__(".symver " RTE_STR(b) RTE_STR(e) ", "RTE_STR(b)"@")
+
+/*
+ * BNID_DEFAULT_SYMBOL
+ * Creates a symbol version entry instructing the linker to bind references to
+ * symbol <b> to the internal symbol <b>_<e>
+ */
+#define BIND_DEFAULT_SYMBOL(b, e, n) __asm__(".symver " RTE_STR(b) RTE_STR(e) ", "RTE_STR(b)"@@DPDK_"RTE_STR(n))
+#define __vsym __attribute__((used))
+
+#else
+/*
+ * No symbol versioning in use
+ */
+#define VERSION_SYMBOL(b, e, v)
+#define __vsym
+#define BASE_SYMBOL(b, n)
+#define BIND_DEFAULT_SYMBOL(b, v)
+
+/*
+ * RTE_BUILD_SHARED_LIB=n
+ */
+#endif
+
+
+#endif /* _RTE_COMPAT_H_ */
diff --git a/mk/rte.lib.mk b/mk/rte.lib.mk
index 81bf8e1..1d3b646 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=$(SRCDIR)/$(EXPORT_MAP)
+
 endif
 
+
 _BUILD = $(LIB)
 _INSTALL = $(INSTALL-FILES-y) $(SYMLINK-FILES-y) $(RTE_OUTPUT)/lib/$(LIB)
 _CLEAN = doclean