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From: Joel Stanley <joel@jms.id.au>
To: linuxppc-dev@lists.ozlabs.org
Cc: Anton Blanchard <anton@samba.org>,
	Anton Blanchard <anton@ozlabs.org>,
	Nick Desaulniers <ndesaulniers@google.com>
Subject: [PATCH v2 4/5] powerpc: Fix duplicate const clang warning in user access code
Date: Fri, 14 Sep 2018 13:36:48 +0930	[thread overview]
Message-ID: <20180914040649.1794-5-joel@jms.id.au> (raw)
In-Reply-To: <20180914040649.1794-1-joel@jms.id.au>

From: Anton Blanchard <anton@samba.org>

This re-applies b91c1e3e7a6f which was reverted in f2ca80905929
d466f6c5cac1 f84ed59a612d (powerpc/sparse: Constify the address pointer
...").

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>
---
If we don't want to apply this, other options are suppressing the
warning, or wait for a fix to land in clang
(https://github.com/ClangBuiltLinux/linux/issues/52).
---
 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 bac225bb7f64..15bea9a0f260 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);	\
-- 
2.17.1

  parent reply	other threads:[~2018-09-14  4:07 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-14  4:06 [PATCH v2 0/5] powerpc: Clang build fixes Joel Stanley
2018-09-14  4:06 ` [PATCH v2 1/5] powerpc/Makefiles: Fix clang/llvm build Joel Stanley
2018-09-14 17:41   ` Nick Desaulniers
2018-09-20  7:04     ` Joel Stanley
2018-09-14  4:06 ` [PATCH v2 2/5] powerpc/boot: Fix crt0.S syntax for clang Joel Stanley
2018-09-14 17:47   ` Nick Desaulniers
2018-09-14 21:08     ` Segher Boessenkool
2018-09-17 20:41       ` Nick Desaulniers
2018-09-18  1:08         ` Joel Stanley
2018-09-18 10:53           ` Michael Ellerman
2018-09-14  4:06 ` [PATCH v2 3/5] powerpc/boot: Ensure _zimage_start is a weak symbol Joel Stanley
2018-09-14 17:50   ` Nick Desaulniers
2018-09-20  4:21   ` [v2,3/5] " Michael Ellerman
2018-09-14  4:06 ` Joel Stanley [this message]
2018-09-14 17:57   ` [PATCH v2 4/5] powerpc: Fix duplicate const clang warning in user access code Nick Desaulniers
2018-09-19  7:45     ` Joel Stanley
2018-09-20  4:54       ` Christophe LEROY
2018-09-20 12:35         ` Michael Ellerman
2018-09-20  4:21   ` [v2, " Michael Ellerman
2018-09-14  4:06 ` [PATCH v2 5/5] powerpc: Remove -mno-sched-epilog Joel Stanley
2018-09-14  5:06   ` Nicholas Piggin
2018-09-14 18:03     ` Nick Desaulniers
2018-09-14 20:43       ` Nicholas Piggin
2018-09-14 21:18         ` Segher Boessenkool
2018-09-14 22:20           ` Nick Desaulniers
2018-09-15  1:04             ` Segher Boessenkool

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