9f7f1a167a
* Wed Sep 09 2020 Fedora Kernel Team <kernel-team@fedoraproject.org> [5.9.0-0.rc4.20200909git34d4ddd359db.5] - Merge ark-patches Resolves: rhbz# Signed-off-by: Justin M. Forbes <jforbes@fedoraproject.org>
215 lines
8.0 KiB
Diff
215 lines
8.0 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Myron Stowe <myron.stowe@redhat.com>
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Date: Fri, 29 Jun 2018 20:05:41 -0400
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Subject: [PATCH] kABI: Add generic kABI macros to use for kABI workarounds
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Message-id: <20180629200436.151355.18581.stgit@tak.stowe>
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Patchwork-id: 223206
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O-Subject: [RHEL8.0 PATCH v3] kABI: Add generic kABI macros to use for kABI workarounds
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Bugzilla: 1546831
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RH-Acked-by: Larry Woodman <lwoodman@redhat.com>
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RH-Acked-by: Jarod Wilson <jarod@redhat.com>
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Some kernel subsystem maintainers have asked about kABI for RHEL8.0
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- getting kABI related "extension" structures and such into place. The
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consensus was to wait until the 4.17 re-base. Now that that's occurred,
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lets get this first step, kABI macros, into RHEL8.0 so developers will
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notice, and use, them in subsequent kABI related efforts.
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Content taken from RHEL 7. No functional change intended.
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Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1546831
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Brew: https://brewweb.devel.redhat.com/taskinfo?taskID=16694565
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Upstream Status: N/A (RHEL only)
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Testing: Passed through brew build.
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Upstream Status: RHEL only
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Signed-off-by: Myron Stowe <myron.stowe@redhat.com>
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Signed-off-by: Herton R. Krzesinski <herton@redhat.com>
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---
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include/linux/rh_kabi.h | 172 ++++++++++++++++++++++++++++++++++++++++
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1 file changed, 172 insertions(+)
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create mode 100644 include/linux/rh_kabi.h
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diff --git a/include/linux/rh_kabi.h b/include/linux/rh_kabi.h
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new file mode 100644
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index 000000000000..e0d3353802bb
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--- /dev/null
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+++ b/include/linux/rh_kabi.h
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@@ -0,0 +1,172 @@
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+/*
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+ * rh_kabi.h - Red Hat kABI abstraction header
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+ *
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+ * Copyright (c) 2014 Don Zickus
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+ * Copyright (c) 2015-2017 Jiri Benc
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+ * Copyright (c) 2015 Sabrina Dubroca, Hannes Frederic Sowa
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+ * Copyright (c) 2016-2018 Prarit Bhargava
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+ * Copyright (c) 2017 Paolo Abeni, Larry Woodman
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+ *
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+ * This file is released under the GPLv2.
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+ * See the file COPYING for more details.
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+ *
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+ * These kabi macros hide the changes from the kabi checker and from the
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+ * process that computes the exported symbols' checksums.
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+ * They have 2 variants: one (defined under __GENKSYMS__) used when
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+ * generating the checksums, and the other used when building the kernel's
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+ * binaries.
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+ *
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+ * The use of these macros does not guarantee that the usage and modification
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+ * of code is correct. As with all Red Hat only changes, an engineer must
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+ * explain why the use of the macro is valid in the patch containing the
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+ * changes.
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+ *
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+ */
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+
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+#ifndef _LINUX_RH_KABI_H
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+#define _LINUX_RH_KABI_H
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+
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+#include <linux/compiler.h>
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+#include <linux/stringify.h>
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+
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+/*
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+ * RH_KABI_CONST
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+ * Adds a new const modifier to a function parameter preserving the old
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+ * checksum.
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+ *
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+ * RH_KABI_DEPRECATE
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+ * Mark the element as deprecated and make it unusable by modules while
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+ * preserving kABI checksums.
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+ *
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+ * RH_KABI_DEPRECATE_FN
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+ * Mark the function pointer as deprecated and make it unusable by modules
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+ * while preserving kABI checksums.
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+ *
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+ * RH_KABI_EXTEND
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+ * Simple macro for adding a new element to a struct.
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+ *
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+ * Warning: only use if a hole exists for _all_ arches. Use pahole to verify.
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+ *
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+ * RH_KABI_FILL_HOLE
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+ * Simple macro for filling a hole in a struct.
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+ *
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+ * RH_KABI_RENAME
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+ * Simple macro for renaming an element without changing its type. This
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+ * macro can be used in bitfields, for example.
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+ *
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+ * NOTE: does not include the final ';'
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+ *
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+ * RH_KABI_REPLACE
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+ * Simple replacement of _orig with a union of _orig and _new.
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+ *
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+ * The RH_KABI_REPLACE* macros attempt to add the ability to use the '_new'
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+ * element while preserving size alignment with the '_orig' element.
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+ *
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+ * The #ifdef __GENKSYMS__ preserves the kABI agreement, while the anonymous
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+ * union structure preserves the size alignment (assuming the '_new' element
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+ * is not bigger than the '_orig' element).
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+ *
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+ * RH_KABI_REPLACE_UNSAFE
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+ * Unsafe version of RH_KABI_REPLACE. Only use for typedefs.
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+ *
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+ * RH_KABI_FORCE_CHANGE
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+ * Force change of the symbol checksum. The argument of the macro is a
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+ * version for cases we need to do this more than once.
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+ *
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+ * This macro does the opposite: it changes the symbol checksum without
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+ * actually changing anything about the exported symbol. It is useful for
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+ * symbols that are not whitelisted, we're changing them in an
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+ * incompatible way and want to prevent 3rd party modules to silently
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+ * corrupt memory. Instead, by changing the symbol checksum, such modules
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+ * won't be loaded by the kernel. This macro should only be used as a
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+ * last resort when all other KABI workarounds have failed.
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+ *
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+ * NOTE
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+ * Don't use ';' after these macros as it messes up the kABI checker by
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+ * changing what the resulting token string looks like. Instead let this
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+ * macro add the ';' so it can be properly hidden from the kABI checker
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+ * (mainly for RH_KABI_EXTEND, but applied to all macros for uniformity).
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+ *
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+ */
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+#ifdef __GENKSYMS__
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+
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+# define RH_KABI_CONST
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+# define RH_KABI_EXTEND(_new)
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+# define RH_KABI_FILL_HOLE(_new)
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+# define RH_KABI_FORCE_CHANGE(ver) __attribute__((rh_kabi_change ## ver))
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+# define RH_KABI_RENAME(_orig, _new) _orig
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+
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+# define _RH_KABI_DEPRECATE(_type, _orig) _type _orig
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+# define _RH_KABI_DEPRECATE_FN(_type, _orig, _args...) _type (*_orig)(_args)
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+# define _RH_KABI_REPLACE(_orig, _new) _orig
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+# define _RH_KABI_REPLACE_UNSAFE(_orig, _new) _orig
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+
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+#else
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+
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+# define RH_KABI_ALIGN_WARNING ". Disable CONFIG_RH_KABI_SIZE_ALIGN_CHECKS if debugging."
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+
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+# define RH_KABI_CONST const
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+# define RH_KABI_EXTEND(_new) _new;
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+# define RH_KABI_FILL_HOLE(_new) _new;
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+# define RH_KABI_FORCE_CHANGE(ver)
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+# define RH_KABI_RENAME(_orig, _new) _new
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+
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+
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+#if IS_BUILTIN(CONFIG_RH_KABI_SIZE_ALIGN_CHECKS)
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+# define __RH_KABI_CHECK_SIZE_ALIGN(_orig, _new) \
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+ union { \
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+ _Static_assert(sizeof(struct{_new;}) <= sizeof(struct{_orig;}), \
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+ __FILE__ ":" __stringify(__LINE__) ": " __stringify(_new) " is larger than " __stringify(_orig) RH_KABI_ALIGN_WARNING); \
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+ _Static_assert(__alignof__(struct{_new;}) <= __alignof__(struct{_orig;}), \
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+ __FILE__ ":" __stringify(__LINE__) ": " __stringify(_orig) " is not aligned the same as " __stringify(_new) RH_KABI_ALIGN_WARNING); \
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+ }
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+#else
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+# define __RH_KABI_CHECK_SIZE_ALIGN(_orig, _new)
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+#endif
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+
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+# define _RH_KABI_DEPRECATE(_type, _orig) _type rh_reserved_##_orig
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+# define _RH_KABI_DEPRECATE_FN(_type, _orig, _args...) \
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+ _type (* rh_reserved_##_orig)(_args)
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+# define _RH_KABI_REPLACE(_orig, _new) \
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+ union { \
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+ _new; \
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+ struct { \
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+ _orig; \
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+ } __UNIQUE_ID(rh_kabi_hide); \
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+ __RH_KABI_CHECK_SIZE_ALIGN(_orig, _new); \
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+ }
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+# define _RH_KABI_REPLACE_UNSAFE(_orig, _new) _new
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+
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+#endif /* __GENKSYMS__ */
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+
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+/* semicolon added wrappers for the RH_KABI_REPLACE macros */
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+# define RH_KABI_DEPRECATE(_type, _orig) _RH_KABI_DEPRECATE(_type, _orig);
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+# define RH_KABI_DEPRECATE_FN(_type, _orig, _args...) \
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+ _RH_KABI_DEPRECATE_FN(_type, _orig, _args);
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+# define RH_KABI_REPLACE(_orig, _new) _RH_KABI_REPLACE(_orig, _new);
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+# define RH_KABI_REPLACE_UNSAFE(_orig, _new) _RH_KABI_REPLACE_UNSAFE(_orig, _new);
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+/*
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+ * Macro for breaking up a random element into two smaller chunks using an
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+ * anonymous struct inside an anonymous union.
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+ */
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+# define RH_KABI_REPLACE2(orig, _new1, _new2) RH_KABI_REPLACE(orig, struct{ _new1; _new2;})
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+
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+# define RH_KABI_RESERVE(n) _RH_KABI_RESERVE(n);
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+/*
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+ * Simple wrappers to replace standard Red Hat reserved elements.
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+ */
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+# define RH_KABI_USE(n, _new) RH_KABI_REPLACE(_RH_KABI_RESERVE(n), _new)
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+/*
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+ * Macros for breaking up a reserved element into two smaller chunks using
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+ * an anonymous struct inside an anonymous union.
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+ */
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+# define RH_KABI_USE2(n, _new1, _new2) RH_KABI_REPLACE(_RH_KABI_RESERVE(n), struct{ _new1; _new2; })
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+
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+/*
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+ * We tried to standardize on Red Hat reserved names. These wrappers
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+ * leverage those common names making it easier to read and find in the
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+ * code.
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+ */
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+# define _RH_KABI_RESERVE(n) unsigned long rh_reserved##n
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+
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+#endif /* _LINUX_RH_KABI_H */
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--
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2.28.0
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