[dpdk-dev,v2,1/4] compat: Add infrastructure to support symbol versioning
diff mbox

Message ID 1419279860-16985-1-git-send-email-nhorman@tuxdriver.com
State Superseded, archived
Headers show

Commit Message

Neil Horman Dec. 22, 2014, 8:24 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
---
 lib/Makefile                   |  1 +
 lib/librte_compat/Makefile     | 38 +++++++++++++++++
 lib/librte_compat/rte_compat.h | 96 ++++++++++++++++++++++++++++++++++++++++++
 mk/rte.lib.mk                  |  9 +++-
 4 files changed, 143 insertions(+), 1 deletion(-)
 create mode 100644 lib/librte_compat/Makefile
 create mode 100644 lib/librte_compat/rte_compat.h

Comments

Sergio Gonzalez Monroy Dec. 23, 2014, 1:27 p.m. UTC | #1
> From: Neil Horman [mailto:nhorman@tuxdriver.com]
> Sent: Monday, December 22, 2014 8:24 PM
> +++ b/lib/librte_compat/Makefile
>[...]
> +
> +include $(RTE_SDK)/mk/rte.vars.mk
> +
> +
> +# install includes
> +SYMLINK-y-include := rte_compat.h
> +
> +include $(RTE_SDK)/mk/rte.lib.mk
>
I just realized that we can avoid doing the _INSTALL change below if we include
mk/rte_install.mk instead of mk/rte_lib.mk, as it is done in librte_net.

Regards,
Sergio

> diff --git a/mk/rte.lib.mk b/mk/rte.lib.mk index 81bf8e1..cbd439b 100644
> --- a/mk/rte.lib.mk
> +++ b/mk/rte.lib.mk
> @@ -40,10 +40,17 @@ VPATH += $(SRCDIR)
> [...]
> +
>  _BUILD = $(LIB)
> -_INSTALL = $(INSTALL-FILES-y) $(SYMLINK-FILES-y)
> $(RTE_OUTPUT)/lib/$(LIB)
> +_INSTALL = $(INSTALL-FILES-y) $(SYMLINK-FILES-y) ifneq ($(LIB),)
> +_INSTALL += $(RTE_OUTPUT)/lib/$(LIB) endif
>  _CLEAN = doclean
> 
>  .PHONY: all
> --
> 1.9.3
Neil Horman Dec. 23, 2014, 3:50 p.m. UTC | #2
On Tue, Dec 23, 2014 at 01:27:32PM +0000, Gonzalez Monroy, Sergio wrote:
> > From: Neil Horman [mailto:nhorman@tuxdriver.com]
> > Sent: Monday, December 22, 2014 8:24 PM
> > +++ b/lib/librte_compat/Makefile
> >[...]
> > +
> > +include $(RTE_SDK)/mk/rte.vars.mk
> > +
> > +
> > +# install includes
> > +SYMLINK-y-include := rte_compat.h
> > +
> > +include $(RTE_SDK)/mk/rte.lib.mk
> >
> I just realized that we can avoid doing the _INSTALL change below if we include
> mk/rte_install.mk instead of mk/rte_lib.mk, as it is done in librte_net.
> 
> Regards,
> Sergio
> 
But doing so limits the compat directory to only install headers, correct? I'm
ok with that mind you, just need to keep it in mind if we ever add any sort of
compatibility code there.

Neil

> > diff --git a/mk/rte.lib.mk b/mk/rte.lib.mk index 81bf8e1..cbd439b 100644
> > --- a/mk/rte.lib.mk
> > +++ b/mk/rte.lib.mk
> > @@ -40,10 +40,17 @@ VPATH += $(SRCDIR)
> > [...]
> > +
> >  _BUILD = $(LIB)
> > -_INSTALL = $(INSTALL-FILES-y) $(SYMLINK-FILES-y)
> > $(RTE_OUTPUT)/lib/$(LIB)
> > +_INSTALL = $(INSTALL-FILES-y) $(SYMLINK-FILES-y) ifneq ($(LIB),)
> > +_INSTALL += $(RTE_OUTPUT)/lib/$(LIB) endif
> >  _CLEAN = doclean
> > 
> >  .PHONY: all
> > --
> > 1.9.3
> 
>

Patch
diff mbox

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..3415c7b
--- /dev/null
+++ b/lib/librte_compat/Makefile
@@ -0,0 +1,38 @@ 
+#   BSD LICENSE
+#
+#   Copyright(c) 2010-2014 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.lib.mk
diff --git a/lib/librte_compat/rte_compat.h b/lib/librte_compat/rte_compat.h
new file mode 100644
index 0000000..d99e362
--- /dev/null
+++ b/lib/librte_compat/rte_compat.h
@@ -0,0 +1,96 @@ 
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2014 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_
+
+/*
+ * 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.
+ * 	char foo(int value, int otherval) { ...}
+ *
+ * 5) Mark the newest version as the default version
+ * 	BIND_DEFAULT_SYMBOL(foo, 1.9);
+ *
+ */
+#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
+#define BASE_SYMBOL(b, n)
+#define BIND_DEFAULT_SYMBOL(b, v)
+
+/*
+ * RTE_BUILD_SHARED_LIB
+ */
+#endif
+
+
+#endif /* _RTE_COMPAT_H_ */
diff --git a/mk/rte.lib.mk b/mk/rte.lib.mk
index 81bf8e1..cbd439b 100644
--- a/mk/rte.lib.mk
+++ b/mk/rte.lib.mk
@@ -40,10 +40,17 @@  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)
+_INSTALL = $(INSTALL-FILES-y) $(SYMLINK-FILES-y)
+ifneq ($(LIB),)
+_INSTALL += $(RTE_OUTPUT)/lib/$(LIB)
+endif
 _CLEAN = doclean
 
 .PHONY: all