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Diffstat (limited to 'lib/librte_compat/rte_compat.h')
-rw-r--r-- | lib/librte_compat/rte_compat.h | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/lib/librte_compat/rte_compat.h b/lib/librte_compat/rte_compat.h new file mode 100644 index 00000000..1c3c8d52 --- /dev/null +++ b/lib/librte_compat/rte_compat.h @@ -0,0 +1,105 @@ +/*- + * BSD LICENSE + * + * Copyright(c) 2015 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. + * + * 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 accommodate + * 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. + * + * Refer to the guidelines document in the docs subdirectory for details on the + * use of these macros + */ + +/* + * Macro Parameters: + * b - function base name + * e - function version extension, to be concatenated with base name + * n - function symbol version string to be applied + * f - function prototype + * p - full function symbol name + */ + +/* + * 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)) + +/* + * BIND_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)) + +/* + * MAP_STATIC_SYMBOL + * If a function has been bifurcated into multiple versions, none of which + * are defined as the exported symbol name in the map file, this macro can be + * used to alias a specific version of the symbol to its exported name. For + * example, if you have 2 versions of a function foo_v1 and foo_v2, where the + * former is mapped to foo@DPDK_1 and the latter is mapped to foo@DPDK_2 when + * building a shared library, this macro can be used to map either foo_v1 or + * foo_v2 to the symbol foo when building a static library, e.g.: + * MAP_STATIC_SYMBOL(void foo(), foo_v2); + */ +#define MAP_STATIC_SYMBOL(f, p) + +#else +/* + * No symbol versioning in use + */ +#define VERSION_SYMBOL(b, e, n) +#define __vsym +#define BIND_DEFAULT_SYMBOL(b, e, n) +#define MAP_STATIC_SYMBOL(f, p) f __attribute__((alias(RTE_STR(p)))) +/* + * RTE_BUILD_SHARED_LIB=n + */ +#endif + + +#endif /* _RTE_COMPAT_H_ */ |