[PATCH AUTOSEL 4.19 031/191] powerpc: Fix duplicate const clang warning in user access code

Sasha Levin
2019-11-10T03:16:22Z

From: Anton Blanchard <anton@samba.org>

[ 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@samba.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 1ca9e37f7cc99..38a25ff8afb76 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -260,7 +260,7 @@ 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(); \
@@ -274,7 +274,7 @@ 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(); \
@@ -288,7 +288,7 @@ 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