Messages in this thread Patch in this message | | | From | Stefan Agner <> | Subject | [PATCH v2 6/6] ARM: uaccess: remove const to avoid duplicate specifier | Date | Sun, 25 Mar 2018 20:09:59 +0200 |
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Some users of get_user use the macro with an argument p which is already specified as static. When using clang this leads to a duplicate specifier: CC arch/arm/kernel/process.o In file included from init/do_mounts.c:15: In file included from ./include/linux/tty.h:7: In file included from ./include/uapi/linux/termios.h:6: In file included from ./arch/arm/include/generated/uapi/asm/termios.h:1: ./include/asm-generic/termios.h:25:6: warning: duplicate 'const' declaration specifier [-Wduplicate-decl-specifier] if (get_user(tmp, &termio->c_iflag) < 0) ^ ./arch/arm/include/asm/uaccess.h:195:3: note: expanded from macro 'get_user' __get_user_check(x, p); \ ^ ./arch/arm/include/asm/uaccess.h:155:12: note: expanded from macro '__get_user_check' register const typeof(*(p)) __user *__p asm("r0") = (p);\
Remove the const attribute from the register declaration to avoid the duplicate const specifier. In a test with ptrace.c and traps.c (both using get_user with non-const arguments for p) the generated code was exactly the same.
Signed-off-by: Stefan Agner <stefan@agner.ch> --- Similar issue has already been discussed here: https://patchwork.kernel.org/patch/9693821/
arch/arm/include/asm/uaccess.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 0bf2347495f1..3d614e90c19f 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -152,7 +152,7 @@ extern int __get_user_64t_4(void *); #define __get_user_check(x, p) \ ({ \ unsigned long __limit = current_thread_info()->addr_limit - 1; \ - register const typeof(*(p)) __user *__p asm("r0") = (p);\ + register typeof(*(p)) __user *__p asm("r0") = (p); \ register typeof(x) __r2 asm("r2"); \ register unsigned long __l asm("r1") = __limit; \ register int __e asm("r0"); \ -- 2.16.2
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