From: Greg Kroah-Hartman Date: Tue, 4 Jun 2019 14:43:53 +0000 (+0200) Subject: 4.14-stable patches X-Git-Tag: v5.1.8~24 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=13a6f089a64c938788ba8943088963b6dfaa49cc;p=thirdparty%2Fkernel%2Fstable-queue.git 4.14-stable patches added patches: compiler-attributes-add-support-for-__copy-gcc-9.patch include-linux-module.h-copy-__init-__exit-attrs-to-init-cleanup_module.patch --- diff --git a/queue-4.14/compiler-attributes-add-support-for-__copy-gcc-9.patch b/queue-4.14/compiler-attributes-add-support-for-__copy-gcc-9.patch new file mode 100644 index 0000000000..45fe7d8bf3 --- /dev/null +++ b/queue-4.14/compiler-attributes-add-support-for-__copy-gcc-9.patch @@ -0,0 +1,96 @@ +From c0d9782f5b6d7157635ae2fd782a4b27d55a6013 Mon Sep 17 00:00:00 2001 +From: Miguel Ojeda +Date: Fri, 8 Feb 2019 23:51:05 +0100 +Subject: Compiler Attributes: add support for __copy (gcc >= 9) +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +From: Miguel Ojeda + +commit c0d9782f5b6d7157635ae2fd782a4b27d55a6013 upstream. + +From the GCC manual: + + copy + copy(function) + + The copy attribute applies the set of attributes with which function + has been declared to the declaration of the function to which + the attribute is applied. The attribute is designed for libraries + that define aliases or function resolvers that are expected + to specify the same set of attributes as their targets. The copy + attribute can be used with functions, variables, or types. However, + the kind of symbol to which the attribute is applied (either + function or variable) must match the kind of symbol to which + the argument refers. The copy attribute copies only syntactic and + semantic attributes but not attributes that affect a symbol’s + linkage or visibility such as alias, visibility, or weak. + The deprecated attribute is also not copied. + + https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html + +The upcoming GCC 9 release extends the -Wmissing-attributes warnings +(enabled by -Wall) to C and aliases: it warns when particular function +attributes are missing in the aliases but not in their target, e.g.: + + void __cold f(void) {} + void __alias("f") g(void); + +diagnoses: + + warning: 'g' specifies less restrictive attribute than + its target 'f': 'cold' [-Wmissing-attributes] + +Using __copy(f) we can copy the __cold attribute from f to g: + + void __cold f(void) {} + void __copy(f) __alias("f") g(void); + +This attribute is most useful to deal with situations where an alias +is declared but we don't know the exact attributes the target has. + +For instance, in the kernel, the widely used module_init/exit macros +define the init/cleanup_module aliases, but those cannot be marked +always as __init/__exit since some modules do not have their +functions marked as such. + +Suggested-by: Martin Sebor +Reviewed-by: Nick Desaulniers +Signed-off-by: Miguel Ojeda +Signed-off-by: Stefan Agner +Signed-off-by: Greg Kroah-Hartman +--- +Changes in v2: +- Fix define of compatibility __copy macro (add symbol argument) + + include/linux/compiler-gcc.h | 4 ++++ + include/linux/compiler_types.h | 4 ++++ + 2 files changed, 8 insertions(+) + +--- a/include/linux/compiler-gcc.h ++++ b/include/linux/compiler-gcc.h +@@ -343,6 +343,10 @@ + #define __designated_init __attribute__((designated_init)) + #endif + ++#if GCC_VERSION >= 90100 ++#define __copy(symbol) __attribute__((__copy__(symbol))) ++#endif ++ + #endif /* gcc version >= 40000 specific checks */ + + #if !defined(__noclone) +--- a/include/linux/compiler_types.h ++++ b/include/linux/compiler_types.h +@@ -230,6 +230,10 @@ struct ftrace_likely_data { + # define __latent_entropy + #endif + ++#ifndef __copy ++# define __copy(symbol) ++#endif ++ + #ifndef __randomize_layout + # define __randomize_layout __designated_init + #endif diff --git a/queue-4.14/include-linux-module.h-copy-__init-__exit-attrs-to-init-cleanup_module.patch b/queue-4.14/include-linux-module.h-copy-__init-__exit-attrs-to-init-cleanup_module.patch new file mode 100644 index 0000000000..cc565c698a --- /dev/null +++ b/queue-4.14/include-linux-module.h-copy-__init-__exit-attrs-to-init-cleanup_module.patch @@ -0,0 +1,80 @@ +From a6e60d84989fa0e91db7f236eda40453b0e44afa Mon Sep 17 00:00:00 2001 +From: Miguel Ojeda +Date: Sat, 19 Jan 2019 20:59:34 +0100 +Subject: include/linux/module.h: copy __init/__exit attrs to init/cleanup_module + +From: Miguel Ojeda + +commit a6e60d84989fa0e91db7f236eda40453b0e44afa upstream. + +The upcoming GCC 9 release extends the -Wmissing-attributes warnings +(enabled by -Wall) to C and aliases: it warns when particular function +attributes are missing in the aliases but not in their target. + +In particular, it triggers for all the init/cleanup_module +aliases in the kernel (defined by the module_init/exit macros), +ending up being very noisy. + +These aliases point to the __init/__exit functions of a module, +which are defined as __cold (among other attributes). However, +the aliases themselves do not have the __cold attribute. + +Since the compiler behaves differently when compiling a __cold +function as well as when compiling paths leading to calls +to __cold functions, the warning is trying to point out +the possibly-forgotten attribute in the alias. + +In order to keep the warning enabled, we decided to silence +this case. Ideally, we would mark the aliases directly +as __init/__exit. However, there are currently around 132 modules +in the kernel which are missing __init/__exit in their init/cleanup +functions (either because they are missing, or for other reasons, +e.g. the functions being called from somewhere else); and +a section mismatch is a hard error. + +A conservative alternative was to mark the aliases as __cold only. +However, since we would like to eventually enforce __init/__exit +to be always marked, we chose to use the new __copy function +attribute (introduced by GCC 9 as well to deal with this). +With it, we copy the attributes used by the target functions +into the aliases. This way, functions that were not marked +as __init/__exit won't have their aliases marked either, +and therefore there won't be a section mismatch. + +Note that the warning would go away marking either the extern +declaration, the definition, or both. However, we only mark +the definition of the alias, since we do not want callers +(which only see the declaration) to be compiled as if the function +was __cold (and therefore the paths leading to those calls +would be assumed to be unlikely). + +Link: https://lore.kernel.org/lkml/20190123173707.GA16603@gmail.com/ +Link: https://lore.kernel.org/lkml/20190206175627.GA20399@gmail.com/ +Suggested-by: Martin Sebor +Acked-by: Jessica Yu +Signed-off-by: Miguel Ojeda +Signed-off-by: Stefan Agner +Signed-off-by: Greg Kroah-Hartman + +--- + include/linux/module.h | 4 ++-- + 1 file changed, 2 insertions(+), 2 deletions(-) + +--- a/include/linux/module.h ++++ b/include/linux/module.h +@@ -128,13 +128,13 @@ extern void cleanup_module(void); + #define module_init(initfn) \ + static inline initcall_t __maybe_unused __inittest(void) \ + { return initfn; } \ +- int init_module(void) __attribute__((alias(#initfn))); ++ int init_module(void) __copy(initfn) __attribute__((alias(#initfn))); + + /* This is only required if you want to be unloadable. */ + #define module_exit(exitfn) \ + static inline exitcall_t __maybe_unused __exittest(void) \ + { return exitfn; } \ +- void cleanup_module(void) __attribute__((alias(#exitfn))); ++ void cleanup_module(void) __copy(exitfn) __attribute__((alias(#exitfn))); + + #endif + diff --git a/queue-4.14/series b/queue-4.14/series index ff7d926a69..6a9f72b41a 100644 --- a/queue-4.14/series +++ b/queue-4.14/series @@ -61,3 +61,5 @@ revert-lockd-show-pid-of-lockd-for-remote-locks.patch gcc-plugins-fix-build-failures-under-darwin-host.patch drm-vmwgfx-don-t-send-drm-sysfs-hotplug-events-on-initial-master-set.patch drm-rockchip-shutdown-drm-subsystem-on-shutdown.patch +compiler-attributes-add-support-for-__copy-gcc-9.patch +include-linux-module.h-copy-__init-__exit-attrs-to-init-cleanup_module.patch