[PATCH AUTOSEL 4.14 013/109] powerpc: Fix duplicate const clang warning in user access code

From: Sasha Levin
Date: Sat Nov 09 2019 - 22:05:41 EST


From: Anton Blanchard <anton@xxxxxxxxx>

[ Upstream commit e00d93ac9a189673028ac125a74b9bc8ae73eebc ]

This re-applies commit b91c1e3e7a6f ("powerpc: Fix duplicate const
clang warning in user access code") (Jun 2015) which was undone in
commits:
f2ca80905929 ("powerpc/sparse: Constify the address pointer in __get_user_nosleep()") (Feb 2017)
d466f6c5cac1 ("powerpc/sparse: Constify the address pointer in __get_user_nocheck()") (Feb 2017)
f84ed59a612d ("powerpc/sparse: Constify the address pointer in __get_user_check()") (Feb 2017)

We see a large number of duplicate const errors in the user access
code when building with llvm/clang:

include/linux/pagemap.h:576:8: warning: duplicate 'const' declaration specifier [-Wduplicate-decl-specifier]
ret = __get_user(c, uaddr);

The problem is we are doing const __typeof__(*(ptr)), which will hit
the warning if ptr is marked const.

Removing const does not seem to have any effect on GCC code
generation.

Signed-off-by: Anton Blanchard <anton@xxxxxxxxx>
Signed-off-by: Joel Stanley <joel@xxxxxxxxx>
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/powerpc/include/asm/uaccess.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index 51f00c00d7e49..3865d1d235976 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -234,7 +234,7 @@ do { \
({ \
long __gu_err; \
__long_type(*(ptr)) __gu_val; \
- const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
+ __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
__chk_user_ptr(ptr); \
if (!is_kernel_addr((unsigned long)__gu_addr)) \
might_fault(); \
@@ -248,7 +248,7 @@ do { \
({ \
long __gu_err = -EFAULT; \
__long_type(*(ptr)) __gu_val = 0; \
- const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
+ __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
might_fault(); \
if (access_ok(VERIFY_READ, __gu_addr, (size))) { \
barrier_nospec(); \
@@ -262,7 +262,7 @@ do { \
({ \
long __gu_err; \
__long_type(*(ptr)) __gu_val; \
- const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
+ __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
__chk_user_ptr(ptr); \
barrier_nospec(); \
__get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
--
2.20.1