linux-kernel - Re: [PATCH v2] powerpc/cell: fix build failure by disabling attribute-alias warning

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Message-ID: <87114f89-0f42-8aa4-f780-dd5832994065@c-s.fr>
Date:   Mon, 18 Jun 2018 09:20:47 +0200
From:   Christophe LEROY <christophe.leroy@....fr>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>, arnd@...db.de
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        Paul Burton <paul.burton@...s.com>
Subject: Re: [PATCH v2] powerpc/cell: fix build failure by disabling
 attribute-alias warning



Le 29/05/2018 à 18:06, Christophe Leroy a écrit :
> Latest GCC version emit the following warnings
> 
> As arch/powerpc code is built with -Werror, this breaks build with
> GCC 8.1
> 
> This patch inhibits those warnings
> 
>    CC      arch/powerpc/platforms/cell/spu_syscalls.o
> In file included from arch/powerpc/platforms/cell/spu_syscalls.c:26:
> ./include/linux/syscalls.h:233:18: error: 'sys_spu_create' alias between functions of incompatible types 'long int(const char *, unsigned int,  umode_t,  int)' {aka 'long int(const char *, unsigned int,  short unsigned int,  int)'} and 'long int(long int,  long int,  long int,  long int)' [-Werror=attribute-alias]
>    asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \
>                    ^~~
> ./include/linux/syscalls.h:222:2: note: in expansion of macro '__SYSCALL_DEFINEx'
>    __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
>    ^~~~~~~~~~~~~~~~~
> ./include/linux/syscalls.h:214:36: note: in expansion of macro 'SYSCALL_DEFINEx'
>   #define SYSCALL_DEFINE4(name, ...) SYSCALL_DEFINEx(4, _##name, __VA_ARGS__)
>                                      ^~~~~~~~~~~~~~~
> arch/powerpc/platforms/cell/spu_syscalls.c:70:1: note: in expansion of macro 'SYSCALL_DEFINE4'
>   SYSCALL_DEFINE4(spu_create, const char __user *, name, unsigned int, flags,
>   ^~~~~~~~~~~~~~~
> ./include/linux/syscalls.h:238:18: note: aliased declaration here
>    asmlinkage long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
>                    ^~~~~~~~
> ./include/linux/syscalls.h:222:2: note: in expansion of macro '__SYSCALL_DEFINEx'
>    __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
>    ^~~~~~~~~~~~~~~~~
> ./include/linux/syscalls.h:214:36: note: in expansion of macro 'SYSCALL_DEFINEx'
>   #define SYSCALL_DEFINE4(name, ...) SYSCALL_DEFINEx(4, _##name, __VA_ARGS__)
>                                      ^~~~~~~~~~~~~~~
> arch/powerpc/platforms/cell/spu_syscalls.c:70:1: note: in expansion of macro 'SYSCALL_DEFINE4'
>   SYSCALL_DEFINE4(spu_create, const char __user *, name, unsigned int, flags,
>   ^~~~~~~~~~~~~~~
> ./include/linux/syscalls.h:233:18: error: 'sys_spu_run' alias between functions of incompatible types 'long int(int,  __u32 *, __u32 *)' {aka 'long int(int,  unsigned int *, unsigned int *)'} and 'long int(long int,  long int,  long int)' [-Werror=attribute-alias]
>    asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \
>                    ^~~
> ./include/linux/syscalls.h:222:2: note: in expansion of macro '__SYSCALL_DEFINEx'
>    __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
>    ^~~~~~~~~~~~~~~~~
> ./include/linux/syscalls.h:213:36: note: in expansion of macro 'SYSCALL_DEFINEx'
>   #define SYSCALL_DEFINE3(name, ...) SYSCALL_DEFINEx(3, _##name, __VA_ARGS__)
>                                      ^~~~~~~~~~~~~~~
> arch/powerpc/platforms/cell/spu_syscalls.c:94:1: note: in expansion of macro 'SYSCALL_DEFINE3'
>   SYSCALL_DEFINE3(spu_run,int, fd, __u32 __user *, unpc, __u32 __user *, ustatus)
>   ^~~~~~~~~~~~~~~
> ./include/linux/syscalls.h:238:18: note: aliased declaration here
>    asmlinkage long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
>                    ^~~~~~~~
> ./include/linux/syscalls.h:222:2: note: in expansion of macro '__SYSCALL_DEFINEx'
>    __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
>    ^~~~~~~~~~~~~~~~~
> ./include/linux/syscalls.h:213:36: note: in expansion of macro 'SYSCALL_DEFINEx'
>   #define SYSCALL_DEFINE3(name, ...) SYSCALL_DEFINEx(3, _##name, __VA_ARGS__)
>                                      ^~~~~~~~~~~~~~~
> arch/powerpc/platforms/cell/spu_syscalls.c:94:1: note: in expansion of macro 'SYSCALL_DEFINE3'
>   SYSCALL_DEFINE3(spu_run,int, fd, __u32 __user *, unpc, __u32 __user *, ustatus)
>   ^~~~~~~~~~~~~~~
> 
> Signed-off-by: Christophe Leroy <christophe.leroy@....fr>

If the serie from Paul Burton 
https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=50442 
goes in, this patch won't be necessary.

Christophe

> ---
> v2: added '#pragma GCC diagnostic ignored "-Wpragmas"' to avoid build failure on old GCC
> 
>   arch/powerpc/platforms/cell/spu_syscalls.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/arch/powerpc/platforms/cell/spu_syscalls.c b/arch/powerpc/platforms/cell/spu_syscalls.c
> index 263413a34823..7862279a82e4 100644
> --- a/arch/powerpc/platforms/cell/spu_syscalls.c
> +++ b/arch/powerpc/platforms/cell/spu_syscalls.c
> @@ -67,6 +67,9 @@ static inline void spufs_calls_put(struct spufs_calls *calls) { }
>   
>   #endif /* CONFIG_SPU_FS_MODULE */
>   
> +#pragma GCC diagnostic push
> +#pragma GCC diagnostic ignored "-Wpragmas"
> +#pragma GCC diagnostic ignored "-Wattribute-alias"
>   SYSCALL_DEFINE4(spu_create, const char __user *, name, unsigned int, flags,
>   	umode_t, mode, int, neighbor_fd)
>   {
> @@ -111,6 +114,7 @@ SYSCALL_DEFINE3(spu_run,int, fd, __u32 __user *, unpc, __u32 __user *, ustatus)
>   	spufs_calls_put(calls);
>   	return ret;
>   }
> +#pragma GCC diagnostic pop
>   
>   #ifdef CONFIG_COREDUMP
>   int elf_coredump_extra_notes_size(void)
>