From: Sasha Levin Date: Tue, 20 Aug 2019 01:49:17 +0000 (-0400) Subject: gcc 9.0 fixes for 4.4 X-Git-Tag: v4.19.68~34 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f1d93daeb314ad177913acaac35a1fe69f42a11f;p=thirdparty%2Fkernel%2Fstable-queue.git gcc 9.0 fixes for 4.4 Signed-off-by: Sasha Levin --- diff --git a/queue-4.4/backport-minimal-compiler_attributes.h-to-support-gc.patch b/queue-4.4/backport-minimal-compiler_attributes.h-to-support-gc.patch new file mode 100644 index 00000000000..159e6541c80 --- /dev/null +++ b/queue-4.4/backport-minimal-compiler_attributes.h-to-support-gc.patch @@ -0,0 +1,49 @@ +From 1e4ca1ca3b4b85dba35abc0343313707e5de580f Mon Sep 17 00:00:00 2001 +From: Miguel Ojeda +Date: Fri, 2 Aug 2019 12:37:56 +0200 +Subject: Backport minimal compiler_attributes.h to support GCC 9 + +This adds support for __copy to v4.9.y so that we can use it in +init/exit_module to avoid -Werror=missing-attributes errors on GCC 9. + +Link: https://lore.kernel.org/lkml/259986242.BvXPX32bHu@devpool35/ +Cc: +Suggested-by: Rolf Eike Beer +Signed-off-by: Miguel Ojeda +Signed-off-by: Greg Kroah-Hartman + +Signed-off-by: Sasha Levin +--- + include/linux/compiler.h | 16 ++++++++++++++++ + 1 file changed, 16 insertions(+) + +diff --git a/include/linux/compiler.h b/include/linux/compiler.h +index ed772311ec1fb..5508011cc0c79 100644 +--- a/include/linux/compiler.h ++++ b/include/linux/compiler.h +@@ -52,6 +52,22 @@ extern void __chk_io_ptr(const volatile void __iomem *); + + #ifdef __KERNEL__ + ++/* ++ * Minimal backport of compiler_attributes.h to add support for __copy ++ * to v4.9.y so that we can use it in init/exit_module to avoid ++ * -Werror=missing-attributes errors on GCC 9. ++ */ ++#ifndef __has_attribute ++# define __has_attribute(x) __GCC4_has_attribute_##x ++# define __GCC4_has_attribute___copy__ 0 ++#endif ++ ++#if __has_attribute(__copy__) ++# define __copy(symbol) __attribute__((__copy__(symbol))) ++#else ++# define __copy(symbol) ++#endif ++ + #ifdef __GNUC__ + #include + #endif +-- +2.20.1 + diff --git a/queue-4.4/include-linux-module.h-copy-__init-__exit-attrs-to-i.patch b/queue-4.4/include-linux-module.h-copy-__init-__exit-attrs-to-i.patch new file mode 100644 index 00000000000..5739f1cee9f --- /dev/null +++ b/queue-4.4/include-linux-module.h-copy-__init-__exit-attrs-to-i.patch @@ -0,0 +1,82 @@ +From 67540d9a03c0fca794083b3f5af93ba246cd542b 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 + +[ Upstream commit a6e60d84989fa0e91db7f236eda40453b0e44afa ] + +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: Sasha Levin +--- + include/linux/module.h | 4 ++-- + 1 file changed, 2 insertions(+), 2 deletions(-) + +diff --git a/include/linux/module.h b/include/linux/module.h +index dfe5c2e25ba1e..d237d0574179e 100644 +--- a/include/linux/module.h ++++ b/include/linux/module.h +@@ -127,13 +127,13 @@ 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 + +-- +2.20.1 + diff --git a/queue-4.4/series b/queue-4.4/series index 7f7686cf2ec..6b32cac7847 100644 --- a/queue-4.4/series +++ b/queue-4.4/series @@ -62,3 +62,5 @@ usb-serial-option-add-d-link-dwm-222-device-id.patch usb-serial-option-add-support-for-zte-mf871a.patch usb-serial-option-add-the-broadmobi-bm818-card.patch usb-serial-option-add-motorola-modem-uarts.patch +backport-minimal-compiler_attributes.h-to-support-gc.patch +include-linux-module.h-copy-__init-__exit-attrs-to-i.patch