diff options
Diffstat (limited to 'target/linux/generic/backport-4.19/013-disable-Wattribute-alias-warning-for-SYSCALL_DEFINEx.patch')
| -rw-r--r-- | target/linux/generic/backport-4.19/013-disable-Wattribute-alias-warning-for-SYSCALL_DEFINEx.patch | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/target/linux/generic/backport-4.19/013-disable-Wattribute-alias-warning-for-SYSCALL_DEFINEx.patch b/target/linux/generic/backport-4.19/013-disable-Wattribute-alias-warning-for-SYSCALL_DEFINEx.patch new file mode 100644 index 0000000000..2440ed8c0d --- /dev/null +++ b/target/linux/generic/backport-4.19/013-disable-Wattribute-alias-warning-for-SYSCALL_DEFINEx.patch @@ -0,0 +1,88 @@ +From: Arnd Bergmann <arnd@arndb.de> +Date: Tue, 19 Jun 2018 13:14:57 -0700 +Subject: [PATCH] disable -Wattribute-alias warning for SYSCALL_DEFINEx() + +gcc-8 warns for every single definition of a system call entry +point, e.g.: + +include/linux/compat.h:56:18: error: 'compat_sys_rt_sigprocmask' alias between functions of incompatible types 'long int(int, compat_sigset_t *, compat_sigset_t *, compat_size_t)' {aka 'long int(int, struct <anonymous> *, struct <anonymous> *, unsigned int)'} and 'long int(long int, long int, long int, long int)' [-Werror=attribute-alias] + asmlinkage long compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))\ + ^~~~~~~~~~ +include/linux/compat.h:45:2: note: in expansion of macro 'COMPAT_SYSCALL_DEFINEx' + COMPAT_SYSCALL_DEFINEx(4, _##name, __VA_ARGS__) + ^~~~~~~~~~~~~~~~~~~~~~ +kernel/signal.c:2601:1: note: in expansion of macro 'COMPAT_SYSCALL_DEFINE4' + COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset, + ^~~~~~~~~~~~~~~~~~~~~~ +include/linux/compat.h:60:18: note: aliased declaration here + asmlinkage long compat_SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__))\ + ^~~~~~~~~~ + +The new warning seems reasonable in principle, but it doesn't +help us here, since we rely on the type mismatch to sanitize the +system call arguments. After I reported this as GCC PR82435, a new +-Wno-attribute-alias option was added that could be used to turn the +warning off globally on the command line, but I'd prefer to do it a +little more fine-grained. + +Interestingly, turning a warning off and on again inside of +a single macro doesn't always work, in this case I had to add +an extra statement inbetween and decided to copy the __SC_TEST +one from the native syscall to the compat syscall macro. See +https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83256 for more details +about this. + +[paul.burton@mips.com: + - Rebase atop current master. + - Split GCC & version arguments to __diag_ignore() in order to match + changes to the preceding patch. + - Add the comment argument to match the preceding patch.] + +Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82435 +Signed-off-by: Arnd Bergmann <arnd@arndb.de> +Signed-off-by: Paul Burton <paul.burton@mips.com> +Tested-by: Christophe Leroy <christophe.leroy@c-s.fr> +Tested-by: Stafford Horne <shorne@gmail.com> +Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> +--- + +--- a/include/linux/compat.h ++++ b/include/linux/compat.h +@@ -48,6 +48,9 @@ + COMPAT_SYSCALL_DEFINEx(6, _##name, __VA_ARGS__) + + #define COMPAT_SYSCALL_DEFINEx(x, name, ...) \ ++ __diag_push(); \ ++ __diag_ignore(GCC, 8, "-Wattribute-alias", \ ++ "Type aliasing is used to sanitize syscall arguments");\ + asmlinkage long compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))\ + __attribute__((alias(__stringify(compat_SyS##name)))); \ + static inline long C_SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ +@@ -56,6 +59,7 @@ + { \ + return C_SYSC##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__)); \ + } \ ++ __diag_pop(); \ + static inline long C_SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__)) + + #ifndef compat_user_stack_pointer +--- a/include/linux/syscalls.h ++++ b/include/linux/syscalls.h +@@ -208,6 +208,9 @@ static inline int is_syscall_trace_event + + #define __PROTECT(...) asmlinkage_protect(__VA_ARGS__) + #define __SYSCALL_DEFINEx(x, name, ...) \ ++ __diag_push(); \ ++ __diag_ignore(GCC, 8, "-Wattribute-alias", \ ++ "Type aliasing is used to sanitize syscall arguments");\ + asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \ + __attribute__((alias(__stringify(SyS##name)))); \ + static inline long SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \ +@@ -219,6 +222,7 @@ static inline int is_syscall_trace_event + __PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \ + return ret; \ + } \ ++ __diag_pop(); \ + static inline long SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__)) + + /* |