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-rw-r--r--recipes-kernel/linux/linux-imx-4.19.35/0002-include-linux-module.h-copy-__init-__exit-attrs-to-i.patch83
1 files changed, 83 insertions, 0 deletions
diff --git a/recipes-kernel/linux/linux-imx-4.19.35/0002-include-linux-module.h-copy-__init-__exit-attrs-to-i.patch b/recipes-kernel/linux/linux-imx-4.19.35/0002-include-linux-module.h-copy-__init-__exit-attrs-to-i.patch
new file mode 100644
index 00000000..78619a5e
--- /dev/null
+++ b/recipes-kernel/linux/linux-imx-4.19.35/0002-include-linux-module.h-copy-__init-__exit-attrs-to-i.patch
@@ -0,0 +1,83 @@
1From 9468870f7cbdb4d7ca828d02d4ff507c01fe591d Mon Sep 17 00:00:00 2001
2From: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
3Date: Sat, 19 Jan 2019 20:59:34 +0100
4Subject: [PATCH] include/linux/module.h: copy __init/__exit attrs to
5 init/cleanup_module
6
7commit a6e60d84989fa0e91db7f236eda40453b0e44afa upstream.
8
9The upcoming GCC 9 release extends the -Wmissing-attributes warnings
10(enabled by -Wall) to C and aliases: it warns when particular function
11attributes are missing in the aliases but not in their target.
12
13In particular, it triggers for all the init/cleanup_module
14aliases in the kernel (defined by the module_init/exit macros),
15ending up being very noisy.
16
17These aliases point to the __init/__exit functions of a module,
18which are defined as __cold (among other attributes). However,
19the aliases themselves do not have the __cold attribute.
20
21Since the compiler behaves differently when compiling a __cold
22function as well as when compiling paths leading to calls
23to __cold functions, the warning is trying to point out
24the possibly-forgotten attribute in the alias.
25
26In order to keep the warning enabled, we decided to silence
27this case. Ideally, we would mark the aliases directly
28as __init/__exit. However, there are currently around 132 modules
29in the kernel which are missing __init/__exit in their init/cleanup
30functions (either because they are missing, or for other reasons,
31e.g. the functions being called from somewhere else); and
32a section mismatch is a hard error.
33
34A conservative alternative was to mark the aliases as __cold only.
35However, since we would like to eventually enforce __init/__exit
36to be always marked, we chose to use the new __copy function
37attribute (introduced by GCC 9 as well to deal with this).
38With it, we copy the attributes used by the target functions
39into the aliases. This way, functions that were not marked
40as __init/__exit won't have their aliases marked either,
41and therefore there won't be a section mismatch.
42
43Note that the warning would go away marking either the extern
44declaration, the definition, or both. However, we only mark
45the definition of the alias, since we do not want callers
46(which only see the declaration) to be compiled as if the function
47was __cold (and therefore the paths leading to those calls
48would be assumed to be unlikely).
49
50Link: https://lore.kernel.org/lkml/20190123173707.GA16603@gmail.com/
51Link: https://lore.kernel.org/lkml/20190206175627.GA20399@gmail.com/
52Suggested-by: Martin Sebor <msebor@gcc.gnu.org>
53Acked-by: Jessica Yu <jeyu@kernel.org>
54Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
55Signed-off-by: Stefan Agner <stefan@agner.ch>
56Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
57---
58 include/linux/module.h | 4 ++--
59 1 file changed, 2 insertions(+), 2 deletions(-)
60
61diff --git a/include/linux/module.h b/include/linux/module.h
62index c710446..9915397 100644
63--- a/include/linux/module.h
64+++ b/include/linux/module.h
65@@ -130,13 +130,13 @@ extern void cleanup_module(void);
66 #define module_init(initfn) \
67 static inline initcall_t __maybe_unused __inittest(void) \
68 { return initfn; } \
69- int init_module(void) __attribute__((alias(#initfn)));
70+ int init_module(void) __copy(initfn) __attribute__((alias(#initfn)));
71
72 /* This is only required if you want to be unloadable. */
73 #define module_exit(exitfn) \
74 static inline exitcall_t __maybe_unused __exittest(void) \
75 { return exitfn; } \
76- void cleanup_module(void) __attribute__((alias(#exitfn)));
77+ void cleanup_module(void) __copy(exitfn) __attribute__((alias(#exitfn)));
78
79 #endif
80
81--
822.7.4
83